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Jungbluth A, Cho E, Privitera A, Yallum KM, Kaienburg P, Lauritzen AE, Derrien T, Kesava SV, Habib I, Pratik SM, Banerji N, Brédas JL, Coropceanu V, Riede M. Limiting factors for charge generation in low-offset fullerene-based organic solar cells. Nat Commun 2024; 15:5488. [PMID: 38942793 DOI: 10.1038/s41467-024-49432-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 06/05/2024] [Indexed: 06/30/2024] Open
Abstract
Free charge generation after photoexcitation of donor or acceptor molecules in organic solar cells generally proceeds via (1) formation of charge transfer states and (2) their dissociation into charge separated states. Research often either focuses on the first component or the combined effect of both processes. Here, we provide evidence that charge transfer state dissociation rather than formation presents a major bottleneck for free charge generation in fullerene-based blends with low energetic offsets between singlet and charge transfer states. We investigate devices based on dilute donor content blends of (fluorinated) ZnPc:C60 and perform density functional theory calculations, device characterization, transient absorption spectroscopy and time-resolved electron paramagnetic resonance measurements. We draw a comprehensive picture of how energies and transitions between singlet, charge transfer, and charge separated states change upon ZnPc fluorination. We find that a significant reduction in photocurrent can be attributed to increasingly inefficient charge transfer state dissociation. With this, our work highlights potential reasons why low offset fullerene systems do not show the high performance of non-fullerene acceptors.
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Affiliation(s)
- Anna Jungbluth
- Department of Physics, The University of Oxford, Oxford, Oxfordshire, OX13PJ, UK
| | - Eunkyung Cho
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, AZ, 85721-0088, USA
- Division of Energy Technology, DGIST, Daegu, 42988, Republic of Korea
| | - Alberto Privitera
- Department of Physics, The University of Oxford, Oxford, Oxfordshire, OX13PJ, UK
- Department of Industrial Engineering and INSTM Research Unit, University of Florence, 50139, Firenze, Italy
| | - Kaila M Yallum
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, 3012, Bern, Switzerland
| | - Pascal Kaienburg
- Department of Physics, The University of Oxford, Oxford, Oxfordshire, OX13PJ, UK
| | - Andreas E Lauritzen
- Department of Physics, The University of Oxford, Oxford, Oxfordshire, OX13PJ, UK
| | - Thomas Derrien
- Diamond Light Source, Didcot, Oxfordshire, OX11 0DE, UK
- Living Systems Institute, University of Exeter, Exeter, EX4 4QD, UK
| | - Sameer V Kesava
- Department of Physics, The University of Oxford, Oxford, Oxfordshire, OX13PJ, UK
| | - Irfan Habib
- Department of Physics, The University of Oxford, Oxford, Oxfordshire, OX13PJ, UK
| | - Saied Md Pratik
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, AZ, 85721-0088, USA
| | - Natalie Banerji
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, 3012, Bern, Switzerland
| | - Jean-Luc Brédas
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, AZ, 85721-0088, USA
| | - Veaceslav Coropceanu
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, AZ, 85721-0088, USA
| | - Moritz Riede
- Department of Physics, The University of Oxford, Oxford, Oxfordshire, OX13PJ, UK.
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2
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Ren J, Zhang S, Chen Z, Zhang T, Qiao J, Wang J, Ma L, Xiao Y, Li Z, Wang J, Hao X, Hou J. Optimizing Molecular Packing via Steric Hindrance for Reducing Non-Radiative Recombination in Organic Solar Cells. Angew Chem Int Ed Engl 2024:e202406153. [PMID: 38730419 DOI: 10.1002/anie.202406153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Revised: 05/10/2024] [Accepted: 05/10/2024] [Indexed: 05/12/2024]
Abstract
Innovative molecule design strategy holds promise for the development of next-generation acceptor materials for efficient organic solar cells with low non-radiative energy loss (ΔEnr). In this study, we designed and prepared three novel acceptors, namely BTP-Biso, BTP-Bme and BTP-B, with sterically structured triisopropylbenzene, trimethylbenzene and benzene as side chains inserted into the shoulder of the central core. The progressively enlarged steric hindrance from BTP-B to BTP-Bme and BTP-Biso induces suppressed intramolecular rotation and altered the molecule packing mode in their aggregation states, leading to significant changes in absorption spectra and energy levels. By regulating the intermolecular π-π interactions, BTP-Bme possesses relatively reduced non-radiative recombination rate and extended exciton diffusion lengths. The binary device based on PB2 : BTP-Bme exhibits an impressive power conversion efficiency (PCE) of 18.5 % with a low ΔEnr of 0.19 eV. Furthermore, the ternary device comprising PB2 : PBDB-TF : BTP-Bme achieves an outstanding PCE of 19.3 %. The molecule design strategy in this study proposed new perspectives for developing high-performance acceptors with low ΔEnr in OSCs.
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Affiliation(s)
- Junzhen Ren
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular, Sciences CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry Chinese Academy of Sciences, 100190, Beijing, China
- School of Chemical Science, University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Shaoqing Zhang
- School of Chemistry and Biology Engineering, University of Science and Technology Beijing, 100083, Beijing, China
| | - Zhihao Chen
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular, Sciences CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry Chinese Academy of Sciences, 100190, Beijing, China
| | - Tao Zhang
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular, Sciences CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry Chinese Academy of Sciences, 100190, Beijing, China
- School of Chemical Science, University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Jiawei Qiao
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, 250100, Shandong, China
| | - Jingwen Wang
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular, Sciences CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry Chinese Academy of Sciences, 100190, Beijing, China
| | - Lijiao Ma
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular, Sciences CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry Chinese Academy of Sciences, 100190, Beijing, China
| | - Yang Xiao
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular, Sciences CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry Chinese Academy of Sciences, 100190, Beijing, China
- School of Chemical Science, University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Zi Li
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular, Sciences CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry Chinese Academy of Sciences, 100190, Beijing, China
| | - Jianqiu Wang
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular, Sciences CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry Chinese Academy of Sciences, 100190, Beijing, China
| | - Xiaotao Hao
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, 250100, Shandong, China
| | - Jianhui Hou
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular, Sciences CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry Chinese Academy of Sciences, 100190, Beijing, China
- School of Chemistry and Biology Engineering, University of Science and Technology Beijing, 100083, Beijing, China
- School of Chemical Science, University of Chinese Academy of Sciences, 100049, Beijing, China
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3
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Zhou W, Chen X, Zhou R, Cai H, Wang Y, Zhang T, Zheng Z, Gao F, Zhang Y, Yan H. The Role of Grain Boundaries on Ion Migration and Charge Recombination in Halide Perovskites. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2310368. [PMID: 38511564 DOI: 10.1002/smll.202310368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 03/07/2024] [Indexed: 03/22/2024]
Abstract
Grain boundaries (GBs) have a significant role in polycrystalline perovskite solar cells (PSCs). However, there is ongoing debate regarding the impact of GBs on the performance and long-term stability of PSCs. Employing the first-principles molecular dynamics for perovskites, the iodine vacancy defect migrations both in bulk and at GBs are investigated. i) The positive iodine vacancy (VI +) is found that have both lower formation energy (1.4 eV) and activation energy (0.18 eV) than those of neutral iodine vacancy (VI), statistically. It indicated the VI + acts as the dominant migrated iodine vacancy rather than VI; ii) the iodine vacancy at GBs has ≈0.48 eV higher activation energy than those in bulk, which leads to the accumulation of iodine vacancy at GBs; iii) the presence of VI + result in a 3-fold increase in charge recombination ratio at GBs, compared to pristine PSCs. Based on quantum molecular dynamics statistical results, which are consistent with experimental measurements, insights into iodine vacancy migration both at GBs and in the bulk are gained. This understanding can be valuable for defects engineering related to ion migration, in order to improve the long-term stability and promote the performance of PSCs.
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Affiliation(s)
- Wencai Zhou
- The Faculty of Materials and Manufacturing, Faculty of Information Technology, Beijing University of Technology, Beijing, 100124, China
| | - Xiaoqing Chen
- The Faculty of Materials and Manufacturing, Faculty of Information Technology, Beijing University of Technology, Beijing, 100124, China
| | - Rongkun Zhou
- The Faculty of Materials and Manufacturing, Faculty of Information Technology, Beijing University of Technology, Beijing, 100124, China
| | - Hongbo Cai
- The Faculty of Materials and Manufacturing, Faculty of Information Technology, Beijing University of Technology, Beijing, 100124, China
| | - Yun Wang
- The Faculty of Materials and Manufacturing, Faculty of Information Technology, Beijing University of Technology, Beijing, 100124, China
| | - Tiankai Zhang
- Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, 58183, Sweden
| | - Zilong Zheng
- The Faculty of Materials and Manufacturing, Faculty of Information Technology, Beijing University of Technology, Beijing, 100124, China
| | - Feng Gao
- Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, 58183, Sweden
| | - Yongzhe Zhang
- The Faculty of Materials and Manufacturing, Faculty of Information Technology, Beijing University of Technology, Beijing, 100124, China
| | - Hui Yan
- The Faculty of Materials and Manufacturing, Faculty of Information Technology, Beijing University of Technology, Beijing, 100124, China
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4
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Song Z, Han J, Henkelman G, Li L. Charge-Optimized Electrostatic Interaction Atom-Centered Neural Network Algorithm. J Chem Theory Comput 2024; 20:2088-2097. [PMID: 38380601 DOI: 10.1021/acs.jctc.3c01254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
Machine-learning algorithms have been proposed to capture electrostatic interactions by using effective partial charges. These algorithms often rely on a pretrained model for partial charge prediction using density functional theory-calculated partial charges as references, which introduces complexity to the force field model. The accuracy of the trained model also depends on the reliability of charge partition methods, which can be dependent on the specific system and methodology employed. In this study, we propose an atom-centered neural network (ANN) algorithm that eliminates the need for reference charges. Our algorithm requires only a single NN model for each element to obtain both atomic energy and charges. These atomic charges are then employed to compute electrostatic energies using the Ewald summation algorithm. Subsequently, the force field model is trained on total energy and forces, with the inclusion of electrostatic energy. To evaluate the performance of our algorithm, we conducted tests on three benchmark systems, including a Ge slab with an O adatom system, a TiO2 crystalline system, and a Pd-O nanoparticle system. Our results demonstrate reasonably accurate predictions of partial charges and electrostatic interactions. This algorithm provides a self-consistent charge prediction strategy and possibilities for robust and reliable modeling of electrostatic interactions in machine-learning potentials.
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Affiliation(s)
- Zichen Song
- Shenzhen Key Laboratory of Micro/Nano-Porous Functional Materials (SKLPM), Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, Hong Kong, China
| | - Jian Han
- Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, Hong Kong, China
| | - Graeme Henkelman
- Department of Chemistry, the University of Texas at Austin, Austin, Texas 78712, United States
- Institute for Computational Engineering and Sciences, the University of Texas at Austin, Austin, Texas 78712, United States
| | - Lei Li
- Shenzhen Key Laboratory of Micro/Nano-Porous Functional Materials (SKLPM), Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
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5
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Zhao J, Liu H, Fan J, Mu Q. A molecular descriptor of a shallow potential energy surface for the ground state to achieve narrowband thermally activated delayed fluorescence emission. Phys Chem Chem Phys 2024; 26:5156-5168. [PMID: 38260957 DOI: 10.1039/d3cp05875a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Narrowband thermally activated delayed fluorescence (TADF) molecules have extensive applications in optoelectronics, biomedicine, and energy. The full-width at half-maximum (FWHM) holds significant importance in assessing the luminescence efficiency and color purity of TADF molecules. The goal is to achieve efficient and stable TADF emissions by regulating and optimizing the FWHM. However, a bridge from the basic physical parameters (such as geometric structure and reorganization energy) to the macroscopic properties (delayed fluorescence, efficiency, and color purity) is needed and it is highly necessary and urgent to explore the internal mechanisms that influence FWHM. Herein, first-principles calculations coupled with the thermal vibration correlation function (TVCF) theory were performed to study the energy consumption processes of the excited states for the three TADF molecules (2,3-POA, 2,3-DPA, and 2,3-CZ) with different donors; inner physical parameters affecting the FWHM were detected. By analyzing the basic geometric and electronic structures as well as the transition properties and reorganization energies, three main findings in modulating FWHM were obtained, namely a large local excitation (LE) proportion in the first singlet excited state is advantageous in reducing FWHM, a donor group with weak electron-donating ability is beneficial for achieving narrowband emission, and small reorganization energies for the ground state are favorable for reducing FWHM. Thus, wise molecular design strategies to achieve efficient narrowband TADF emission are theoretically proven and proposed. We hope that these results will promote an in-depth understanding of FWHM and accelerate the development of high color purity TADF emitters.
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Affiliation(s)
- Jiaqiang Zhao
- School of Physics and Electronic Information, Weifang University, Weifang 261061, China.
| | - Huanling Liu
- Shandong Province Key Laboratory of Medical Physics and Image Processing Technology, Institute of Materials and Clean Energy, School of Physics and Electronics, Shandong Normal University, Jinan 250014, China.
| | - Jianzhong Fan
- Shandong Province Key Laboratory of Medical Physics and Image Processing Technology, Institute of Materials and Clean Energy, School of Physics and Electronics, Shandong Normal University, Jinan 250014, China.
| | - Qingfang Mu
- Shandong Province Key Laboratory of Medical Physics and Image Processing Technology, Institute of Materials and Clean Energy, School of Physics and Electronics, Shandong Normal University, Jinan 250014, China.
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6
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Lüer L, Wang R, Liu C, Dube H, Heumüller T, Hauch J, Brabec CJ. Maximizing Performance and Stability of Organic Solar Cells at Low Driving Force for Charge Separation. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2305948. [PMID: 38039433 PMCID: PMC10853714 DOI: 10.1002/advs.202305948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 10/19/2023] [Indexed: 12/03/2023]
Abstract
Thanks to the development of novel electron acceptor materials, the power conversion efficiencies (PCE) of organic photovoltaic (OPV) devices are now approaching 20%. Further improvement of PCE is complicated by the need for a driving force to split strongly bound excitons into free charges, causing voltage losses. This review discusses recent approaches to finding efficient OPV systems with minimal driving force, combining near unity quantum efficiency (maximum short circuit currents) with optimal energy efficiency (maximum open circuit voltages). The authors discuss apparently contradicting results on the amount of exciton binding in recent literature, and approaches to harmonize the findings. A comprehensive view is then presented on motifs providing a driving force for charge separation, namely hybridization at the donor:acceptor interface and polarization effects in the bulk, of which quadrupole moments (electrostatics) play a leading role. Apart from controlling the energies of the involved states, these motifs also control the dynamics of recombination processes, which are essential to avoid voltage and fill factor losses. Importantly, all motifs are shown to depend on both molecular structure and process conditions. The resulting high dimensional search space advocates for high throughput (HT) workflows. The final part of the review presents recent HT studies finding consolidated structure-property relationships in OPV films and devices from various deposition methods, from research to industrial upscaling.
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Affiliation(s)
- Larry Lüer
- Institute of Materials for Electronics and Energy Technology (i‐MEET)Friedrich‐Alexander‐Universität Erlangen‐NürnbergMartensstrasse 791058ErlangenGermany
| | - Rong Wang
- Institute of Materials for Electronics and Energy Technology (i‐MEET)Friedrich‐Alexander‐Universität Erlangen‐NürnbergMartensstrasse 791058ErlangenGermany
- Erlangen Graduate School in Advanced Optical Technologies (SAOT)Paul‐Gordan‐Straße 691052ErlangenGermany
| | - Chao Liu
- Institute of Materials for Electronics and Energy Technology (i‐MEET)Friedrich‐Alexander‐Universität Erlangen‐NürnbergMartensstrasse 791058ErlangenGermany
| | - Henry Dube
- Department Chemistry and PharmacyFriedrich‐Alexander‐Universität Erlangen‐NürnbergNikolaus‐Fiebiger‐Straße 1091058ErlangenGermany
| | - Thomas Heumüller
- Institute of Materials for Electronics and Energy Technology (i‐MEET)Friedrich‐Alexander‐Universität Erlangen‐NürnbergMartensstrasse 791058ErlangenGermany
| | - Jens Hauch
- Helmholtz‐Institute Erlangen‐Nürnberg (HI‐ERN)Immerwahrstraße 291058ErlangenGermany
| | - Christoph J. Brabec
- Institute of Materials for Electronics and Energy Technology (i‐MEET)Friedrich‐Alexander‐Universität Erlangen‐NürnbergMartensstrasse 791058ErlangenGermany
- Helmholtz‐Institute Erlangen‐Nürnberg (HI‐ERN)Immerwahrstraße 291058ErlangenGermany
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7
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Chen K, Luo Y, Sun M, Liu C, Jia M, Fu C, Shen X, Li C, Zheng X, Pu X, Huang Y, Lu Z. Acquiring Charge-Transfer-Featured Single-Molecule Ultralong Organic Room Temperature Phosphorescence via Through-Space Electronic Coupling. Angew Chem Int Ed Engl 2024; 63:e202314447. [PMID: 37968894 DOI: 10.1002/anie.202314447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 11/08/2023] [Accepted: 11/15/2023] [Indexed: 11/17/2023]
Abstract
Although long-lived triplet charge-transfer (3 CT) state with high energy level has gained significant attention, the development of organic small molecules capable of achieving such states remains a major challenge. Herein, by using the through-space electronic coupling effect, we have developed a compound, namely NIC-DMAC, which has a long-lived 3 CT state at the single-molecule level with a lifetime of 210 ms and a high energy level of up to 2.50 eV. Through a combination of experimental and computational approaches, we have elucidated the photophysical processes of NIC-DMAC, which involve sequential transitions from the first singlet excited state (S1 ) that shows a 1 CT character to the first triplet excited state (T1 ) that exhibits a local excited state feature (3 LE), and then to the second triplet excited state (T2 ) that shows a 3 CT character (i.e., S1 (1 CT)→T1 (3 LE)→T2 (3 CT)). The long lifetime and high energy level of its 3 CT state have enabled NIC-DMAC as an initiator for photocuring in double patterning applications.
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Affiliation(s)
- Kuan Chen
- Key Laboratory of Green Chemistry and Technology (Ministry of Education), College of Chemistry, Sichuan University, Chengdu, 610064, China
| | - Yanju Luo
- Analytical & Testing Center, Sichuan University, Chengdu, 610064, China
| | - Ming Sun
- Key Laboratory of Green Chemistry and Technology (Ministry of Education), College of Chemistry, Sichuan University, Chengdu, 610064, China
| | - Chuanhao Liu
- Key Laboratory of Green Chemistry and Technology (Ministry of Education), College of Chemistry, Sichuan University, Chengdu, 610064, China
| | - Mengjiao Jia
- Key Laboratory of Green Chemistry and Technology (Ministry of Education), College of Chemistry, Sichuan University, Chengdu, 610064, China
| | - Caixia Fu
- Key Laboratory of Green Chemistry and Technology (Ministry of Education), College of Chemistry, Sichuan University, Chengdu, 610064, China
| | - Xingsha Shen
- Key Laboratory of Green Chemistry and Technology (Ministry of Education), College of Chemistry, Sichuan University, Chengdu, 610064, China
| | - Chuan Li
- Key Laboratory of Green Chemistry and Technology (Ministry of Education), College of Chemistry, Sichuan University, Chengdu, 610064, China
| | - Xujun Zheng
- Key Laboratory of Green Chemistry and Technology (Ministry of Education), College of Chemistry, Sichuan University, Chengdu, 610064, China
| | - Xuemei Pu
- Key Laboratory of Green Chemistry and Technology (Ministry of Education), College of Chemistry, Sichuan University, Chengdu, 610064, China
| | - Yan Huang
- Key Laboratory of Green Chemistry and Technology (Ministry of Education), College of Chemistry, Sichuan University, Chengdu, 610064, China
| | - Zhiyun Lu
- Key Laboratory of Green Chemistry and Technology (Ministry of Education), College of Chemistry, Sichuan University, Chengdu, 610064, China
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Fernandes RS, Kumari J, Sriram D, Dey N. Fluorescent Nanoassembly of Tetrazole-Based Dyes with Amphoteric Surfactants: Investigation of Cyanide Sensing and Antitubercular Activity. ACS APPLIED BIO MATERIALS 2023; 6:4158-4167. [PMID: 37737110 DOI: 10.1021/acsabm.3c00357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/23/2023]
Abstract
Tetrazole-based easily synthesizable fluorogenic probes have been developed that can form self-assembled nanostructures in the aqueous medium. Though the compounds could achieve detection of cyanide ions in apolar solvents, such as, THF, significant interference was observed from other basic anions, such as F-, AcO-, H2PO4-, etc. On the other hand, a highly specific response was observed for CN- ions in the aqueous medium. However, the sensitivity was so poor that it could hardly be useful for real-life sample analysis. Interestingly, the co-assembly of such probe molecules with hydroxyethyl-anchored amphoteric surfactants could drastically improve the sensitivity toward CN- ions in water without dampening their excellent selectivity. Also, it was observed that the degree of fluorescence response for CN- ions depends on the nature of the polyaromatic scaffolds (naphthyl vs anthracenyl), the nature of the surfactant assembly (micelle vs vesicle), etc. The mechanistic investigation indicates the hydrogen bonding interaction between the tetrazole -NH group and cyanide ions in the aqueous medium, which can effectively change the electronics of the tetrazole unit, resulting in alteration in the extent of charge transfer interaction. Then, the biocompatible composite materials (dye-surfactant assemblies at different ratios) were tested for antituberculosis activity. Fortunately, in a few cases, the compositions were found to be as effective as the commercially available antituberculosis drug, ethambutol.
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Affiliation(s)
- Rikitha S Fernandes
- Department of Chemistry, BITS-Pilani Hyderabad Campus, Hyderabad 500078, India
| | - Jyothi Kumari
- Department of Pharmacy, BITS-Pilani Hyderabad Campus, Hyderabad 500078, India
| | - Dharmarajan Sriram
- Department of Pharmacy, BITS-Pilani Hyderabad Campus, Hyderabad 500078, India
| | - Nilanjan Dey
- Department of Chemistry, BITS-Pilani Hyderabad Campus, Hyderabad 500078, India
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9
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Cui Y, Zhu P, Hu H, Xia X, Lu X, Yu S, Tempeld H, Eichel RA, Liao X, Chen Y. Impact of Electrostatic Interaction on Non-radiative Recombination Energy Losses in Organic Solar Cells Based on Asymmetric Acceptors. Angew Chem Int Ed Engl 2023; 62:e202304931. [PMID: 37431837 DOI: 10.1002/anie.202304931] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 07/07/2023] [Accepted: 07/10/2023] [Indexed: 07/12/2023]
Abstract
Reducing non-radiative recombination energy loss (ΔE3 ) is one key to boosting the efficiency of organic solar cells. Although the recent studies have indicated that the Y-series asymmetric acceptors-based devices featured relatively low ΔE3 , the understanding of the energy loss mechanism derived from molecular structure change is still lagging behind. Herein, two asymmetric acceptors named BTP-Cl and BTP-2Cl with different terminals were synthesized to make a clear comparative study with the symmetric acceptor BTP-0Cl. Our results suggest that asymmetric acceptors exhibit a larger difference of electrostatic potential (ESP) in terminals and semi-molecular dipole moment, which contributes to form a stronger π-π interaction. Besides, the experimental and theoretical studies reveal that a lower ESP-induced intermolecular interaction can reduce the distribution of PM6 near the interface to enhance the built-in potential and decrease the charge transfer state ratio for asymmetric acceptors. Therefore, the devices achieve a higher exciton dissociation efficiency and lower ΔE3 . This work establishes a structure-performance relationship and provides a new perspective to understand the state-of-the-art asymmetric acceptors.
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Affiliation(s)
- Yongjie Cui
- National Engineering Research Center for Carbohydrate Synthesis/Key Laboratory of Fluorine and Silicon for Energy Materials and Chemistry of Ministry of Education, Jiangxi Normal University, 99 Ziyang Avenue, Nanchang, 330022, China
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials & College of Materials Science and Engineering, Donghua University, 2999 North Renmin Road, Shanghai, 201620, China
| | - Peipei Zhu
- National Engineering Research Center for Carbohydrate Synthesis/Key Laboratory of Fluorine and Silicon for Energy Materials and Chemistry of Ministry of Education, Jiangxi Normal University, 99 Ziyang Avenue, Nanchang, 330022, China
| | - Huawei Hu
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials & College of Materials Science and Engineering, Donghua University, 2999 North Renmin Road, Shanghai, 201620, China
| | - Xinxin Xia
- Department of Physics, Chinese University of Hong Kong, Hong Kong, 999077, China
| | - Xinhui Lu
- Department of Physics, Chinese University of Hong Kong, Hong Kong, 999077, China
| | - Shicheng Yu
- Institut für Energie- und Klimaforschung (IEK-9: Grundlagen der Elektrochemie), Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Hermann Tempeld
- Institut für Energie- und Klimaforschung (IEK-9: Grundlagen der Elektrochemie), Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Rüdiger-A Eichel
- Institut für Energie- und Klimaforschung (IEK-9: Grundlagen der Elektrochemie), Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Xunfan Liao
- National Engineering Research Center for Carbohydrate Synthesis/Key Laboratory of Fluorine and Silicon for Energy Materials and Chemistry of Ministry of Education, Jiangxi Normal University, 99 Ziyang Avenue, Nanchang, 330022, China
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials & College of Materials Science and Engineering, Donghua University, 2999 North Renmin Road, Shanghai, 201620, China
| | - Yiwang Chen
- National Engineering Research Center for Carbohydrate Synthesis/Key Laboratory of Fluorine and Silicon for Energy Materials and Chemistry of Ministry of Education, Jiangxi Normal University, 99 Ziyang Avenue, Nanchang, 330022, China
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials & College of Materials Science and Engineering, Donghua University, 2999 North Renmin Road, Shanghai, 201620, China
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10
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Zong X, Yang Y, Yin S. The Energy Structure of Spin States in Reducing the Nonradiative Voltage Loss in Organic Solar Cells. J Phys Chem Lett 2023; 14:7490-7497. [PMID: 37581406 DOI: 10.1021/acs.jpclett.3c01918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/16/2023]
Abstract
In organic solar cells (OSCs), the nonradiative voltage loss (ΔVnr) has been identified as a critical factor for the relatively lower open-circuit voltage. Under open-circuit conditions, most of the charge recombination processes occur via the triplet exciton state, underscoring the importance of the energy structures concerning the local exciton (LE) and charge transfer (CT) spin states. In this Letter, we propose a five-state model to explore the spin state energy structures to reduce ΔVnr. Our calculations reveal that, to minimize ΔVnr, the spin singlet state for LE should possess a lower energy than the triplet state, ES1 < ET1. In contrast, the energies of the CT spin states have a negligible effect on ΔVnr. We identify the best energy structure as ES1 < ET1 ∼ ECT1/CT3. Moreover, our calculations demonstrate that strong couplings between these spin states, particularly involving spin flip, can effectively mitigate ΔVnr. These findings present novel insights for the advancement of OSCs.
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Affiliation(s)
- Xin Zong
- School of Physics, Shandong University, Jinan 250100, People's Republic of China
| | - Yawen Yang
- School of Physics, Shandong University, Jinan 250100, People's Republic of China
| | - Sun Yin
- School of Physics, Shandong University, Jinan 250100, People's Republic of China
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11
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Jiang Y, Li Y, Liu F, Wang W, Su W, Liu W, Liu S, Zhang W, Hou J, Xu S, Yi Y, Zhu X. Suppressing electron-phonon coupling in organic photovoltaics for high-efficiency power conversion. Nat Commun 2023; 14:5079. [PMID: 37604923 PMCID: PMC10442373 DOI: 10.1038/s41467-023-40806-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 08/10/2023] [Indexed: 08/23/2023] Open
Abstract
The nonradiative energy loss (∆Enr) is a critical factor to limit the efficiency of organic solar cells. Generally, strong electron-phonon coupling induced by molecular motion generates fast nonradiative decay and causes high ∆Enr. How to restrict molecular motion and achieve a low ∆Enr is a sticking point. Herein, the free volume ratio (FVR) is proposed as an indicator to evaluate molecular motion, providing new molecular design rationale to suppress nonradiative decay. Theoretical and experimental results indicate proper proliferation of alkyl side-chain can decrease FVR and restrict molecular motion, leading to reduced electron-phonon coupling while maintaining ideal nanomorphology. The reduced FVR and favorable morphology are simultaneously obtained in AQx-6 with pinpoint alkyl chain proliferation, achieving a high PCE of 18.6% with optimized VOC, JSC and FF. Our study discovered aggregation-state regulation is of great importance to the reduction of electron-phonon coupling, which paves the way to high-efficiency OSCs.
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Affiliation(s)
- Yuanyuan Jiang
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yixin Li
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Feng Liu
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Wenxuan Wang
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Wenli Su
- Department of Physics and Applied Optics, Beijing Area Major Laboratory Center for Advanced Quantum Studies, Beijing Normal University, Beijing, 100875, China
| | - Wuyue Liu
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Songjun Liu
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Wenkai Zhang
- Department of Physics and Applied Optics, Beijing Area Major Laboratory Center for Advanced Quantum Studies, Beijing Normal University, Beijing, 100875, China
| | - Jianhui Hou
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Shengjie Xu
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
| | - Yuanping Yi
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
| | - Xiaozhang Zhu
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
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12
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Zarrabi N, Sandberg OJ, Meredith P, Armin A. Subgap Absorption in Organic Semiconductors. J Phys Chem Lett 2023; 14:3174-3185. [PMID: 36961944 PMCID: PMC10084470 DOI: 10.1021/acs.jpclett.3c00021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 03/06/2023] [Indexed: 06/18/2023]
Abstract
Organic semiconductors have found a broad range of application in areas such as light emission, photovoltaics, and optoelectronics. The active components in such devices are based on molecular and polymeric organic semiconductors, where the density of states is generally determined by the disordered nature of the molecular solid rather than energy bands. Inevitably, there exist states within the energy gap which may include tail states, deep traps caused by unavoidable impurities and defects, as well as intermolecular states due to (radiative) charge transfer states. In this Perspective, we first summarize methods to determine the absorption features due to the subgap states. We then explain how subgap states can be parametrized based upon the subgap spectral line shapes. We finally describe the role of subgap states in the performance metrics of organic semiconductor devices from a thermodynamic viewpoint.
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Affiliation(s)
- Nasim Zarrabi
- Sustainable
Advanced Materials (Ser-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, United Kingdom
| | - Oskar J. Sandberg
- Sustainable
Advanced Materials (Ser-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, United Kingdom
| | - Paul Meredith
- Sustainable
Advanced Materials (Ser-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, United Kingdom
| | - Ardalan Armin
- Sustainable
Advanced Materials (Ser-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, United Kingdom
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13
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Kim T, Feng Y, O'Connor JP, Stoddart JF, Young RM, Wasielewski MR. Coherent Vibronic Wavepackets Show Structure-Directed Charge Flow in Host-Guest Donor-Acceptor Complexes. J Am Chem Soc 2023. [PMID: 37018535 DOI: 10.1021/jacs.2c13576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023]
Abstract
Designing and controlling charge transfer (CT) pathways in organic semiconductors are important for solar energy applications. To be useful, a photogenerated, Coulombically bound CT exciton must further separate into free charge carriers; direct observations of the detailed CT relaxation pathways, however, are lacking. Here, photoinduced CT and relaxation dynamics in three host-guest complexes, where a perylene (Per) electron donor guest is incorporated into two symmetric and one asymmetric extended viologen cyclophane acceptor hosts, are presented. The central ring in the extended viologen is either p-phenylene (ExV2+) or electron-rich 2,5-dimethoxy-p-phenylene (ExMeOV2+), resulting in two symmetric cyclophanes with unsubstituted or methoxy-substituted central rings, ExBox4+ and ExMeOBox4+, respectively, and an asymmetric cyclophane with one of the central viologen rings being methoxylated ExMeOVBox4+. Upon photoexcitation, the asymmetric host-guest ExMeOVBox4+ ⊃ Per complex exhibits directional CT toward the energetically unfavorable methoxylated side due to structural restrictions that facilitate strong interactions between the Per donor and the ExMeOV2+ side. The CT state relaxation pathways are probed using ultrafast optical spectroscopy by focusing on coherent vibronic wavepackets, which are used to identify CT relaxations along charge localization and vibronic decoherence coordinates. Specific low- and high-frequency nuclear motions are direct indicators of a delocalized CT state and the degree of CT character. Our results show that the CT pathway can be controlled by subtle chemical modifications of the acceptor host in addition to illustrating how coherent vibronic wavepackets can be used to probe the nature and time evolution of the CT states.
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Affiliation(s)
- Taeyeon Kim
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Yuanning Feng
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - James P O'Connor
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - J Fraser Stoddart
- Stoddart Institute of Molecular Science, Department of Chemistry, Zhejiang University, Hangzhou 310027, China
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou 311215, China
- School of Chemistry, University of New South Wales, Sydney, New South Wales 2052, Australia
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Ryan M Young
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Michael R Wasielewski
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
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14
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Shi F, Guo P, Qiao X, Yao G, Zhang T, Lu Q, Wang Q, Wang X, Rikhsibaev J, Wang E, Zhang C, Kwon YW, Woo HY, Wu H, Hou J, Ma D, Armin A, Ma Y, Xia Y. A Nitroxide Radical Conjugated Polymer as an Additive to Reduce Nonradiative Energy Loss in Organic Solar Cells. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023:e2212084. [PMID: 36924360 DOI: 10.1002/adma.202212084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Revised: 02/23/2023] [Indexed: 05/17/2023]
Abstract
Nonfullerene-acceptor-based organic solar cells (NFA-OSCs) are now set off to the 20% power conversion efficiency milestone. To achieve this, minimizing all loss channels, including nonradiative photovoltage losses, seems a necessity. Nonradiative recombination, to a great extent, is known to be an inherent material property due to vibrationally induced decay of charge-transfer (CT) states or their back electron transfer to the triplet excitons. Herein, it is shown that the use of a new conjugated nitroxide radical polymer with 2,2,6,6-tetramethyl piperidine-1-oxyl side groups (GDTA) as an additive results in an improvement of the photovoltaic performance of NFA-OSCs based on different active layer materials. Upon the addition of GDTA, the open-circuit voltage (VOC ), fill factor (FF), and short-circuit current density (JSC ) improve simultaneously. This approach is applied to several material systems including state-of-the-art donor/acceptor pairs showing improvement from 15.8% to 17.6% (in the case of PM6:Y6) and from 17.5% to 18.3% (for PM6:BTP-eC9). Then, the possible reasons behind the observed improvements are discussed. The results point toward the suppression of the CT state to triplet excitons loss channel. This work presents a facile, promising, and generic approach to further improve the performance of NFA-OSCs.
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Affiliation(s)
- Furong Shi
- Organic Semiconductor Materials and Applied Technology Research Centre of Gansu Province, School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, P. R. China
| | - Pengzhi Guo
- Organic Semiconductor Materials and Applied Technology Research Centre of Gansu Province, School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, P. R. China
- National Green Coating Equipment and Technology Research Centre, Lanzhou Jiaotong University, Lanzhou, 730070, P. R. China
| | - Xianfeng Qiao
- State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Guo Yao
- National Laboratory of Solid-State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China
| | - Tao Zhang
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular Sciences CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Qi Lu
- Organic Semiconductor Materials and Applied Technology Research Centre of Gansu Province, School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, P. R. China
| | - Qian Wang
- Organic Semiconductor Materials and Applied Technology Research Centre of Gansu Province, School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, P. R. China
| | - Xiaofeng Wang
- Organic Semiconductor Materials and Applied Technology Research Centre of Gansu Province, School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, P. R. China
| | - Jasurbek Rikhsibaev
- Organic Semiconductor Materials and Applied Technology Research Centre of Gansu Province, School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, P. R. China
| | - Ergang Wang
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Göteborg, SE-412 96, Sweden
| | - Chunfeng Zhang
- National Laboratory of Solid-State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China
| | - Young-Wan Kwon
- Department of Chemistry, KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Republic of Korea
| | - Han Young Woo
- Department of Chemistry, KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Republic of Korea
| | - Hongbin Wu
- State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Jianhui Hou
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular Sciences CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Dongge Ma
- State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Ardalan Armin
- Sustainable Advanced Materials (Sêr SAM), Department of Physics, Swansea University, Singleton Park, Swansea, SA2 8PP, UK
| | - Yuguang Ma
- Organic Semiconductor Materials and Applied Technology Research Centre of Gansu Province, School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, P. R. China
| | - Yangjun Xia
- Organic Semiconductor Materials and Applied Technology Research Centre of Gansu Province, School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, P. R. China
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15
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Kashani S, Wang Z, Risko C, Ade H. Relating reorganization energies, exciton diffusion length and non-radiative recombination to the room temperature UV-vis absorption spectra of NF-SMA. MATERIALS HORIZONS 2023; 10:443-453. [PMID: 36515185 DOI: 10.1039/d2mh01228f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Understanding excited-state reorganization energies, exciton diffusion lengths and non-radiative (NR) recombination, and the overall optoelectronic responses of nonfullerene small molecule acceptors (NF-SMAs) is important in order to rationally design new materials with controlled properties. While the effects of structural modifications on the optical gaps and electron affinities of NF-SMAs have been studied extensively, analyses of their absorption spectra that carefully characterize electronic and vibrational contributions that allow comparisons of reorganization energies and their implications for exciton diffusion lengths and NR recombination have yet to be reported. Here, we study the room temperature absorption spectra of three structural classes of NF-SMAs in dilute solutions through multiparameter Franck Condon (MFC) analyses and density functional theory (DFT) calculations. We show that the absorption spectra of these NF-SMAs can be categorized based on molecular structure-spectra correlation. The absorption spectra of curved, Y6-like structures can be described using an MFC model with two electronic transitions and two effective vibrational modes. The results of MFC/DFT analyses reveal that Y6 exhibits the smallest intra-molecular reorganization energy among the materials studied. Linear ITIC-like molecular structures reveal larger reorganization energies and reduced conformational uniformity compared to Y6. Meanwhile structures such as IDTBR and IEICO, which have an extra π-conjugated moiety between the donor and acceptor moieties, have large excited-state reorganization energies and low degrees of conformational uniformity. Since the intra-molecular reorganization energy is correlated with exciton diffusion length and nonradiative voltage losses (ΔVnr), our results highlight the power of RT absorption spectroscopy and DFT calculations as simple tools to designing improved OSCs materials with small reorganization energies, small ΔVnr, large exciton diffusion length and low energetic disorder (due to a strongly dominant conformation).
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Affiliation(s)
- Somayeh Kashani
- Department of Physics and Organic and Carbon Electronics Laboratories (ORaCEL), North Carolina State University, Raleigh, NC, 27695, USA.
| | - Zhen Wang
- Department of Physics and Organic and Carbon Electronics Laboratories (ORaCEL), North Carolina State University, Raleigh, NC, 27695, USA.
| | - Chad Risko
- Department of Chemistry and Center for Applied Energy Research (CAER), University of Kentucky, Lexington, Kentucky, 40506, USA
| | - Harald Ade
- Department of Physics and Organic and Carbon Electronics Laboratories (ORaCEL), North Carolina State University, Raleigh, NC, 27695, USA.
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16
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Lu C, Cho E, Cui Z, Gao Y, Cao W, Brédas JL, Coropceanu V, Li F. Towards Efficient and Stable Donor-Acceptor Luminescent Radicals. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2208190. [PMID: 36417767 DOI: 10.1002/adma.202208190] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 11/01/2022] [Indexed: 06/16/2023]
Abstract
In contrast to closed-shell luminescent molecules, the electronic ground state and lowest excited state in organic luminescent radicals are both spin doublet, which results in spin-allowed radiative transitions. Most reported luminescent radicals with high photoluminescent quantum efficiency (PLQE) have a donor-acceptor (D-A•) chemical structure where an electron-donating group is covalently attached to an electron-withdrawing radical core (A•). Understanding the main factors that define the efficiency and stability of D-A• type luminescent radicals remains challenging. Here, we designed and synthesized a series of tri(2,4,6-trichlorophenyl)methyl (TTM) radical derivatives with donor substituents varying by their extent of conjugation and their number of imine-type nitrogen atoms. The experimental results suggest that the luminescence efficiency and stability of the radicals are proportional to the degree of conjugation but inversely proportional to the number of imine nitrogen atoms in the substituents. These experimental trends are very well reproduced by density functional theory calculations. The theoretical results indicate that both the luminescence efficiency and radical stability are related to the energy difference between the charge transfer (CT) and local-excitation (LE) states, which decreases as either the number of imine nitrogen atoms in the substituent increases or its conjugation length decreases.
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Affiliation(s)
- Chen Lu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Eunkyung Cho
- Department of Chemistry and Biochemistry, University of Arizona College of Science, Tucson, AZ, 85721-0088, USA
| | - Zhiyuan Cui
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Yuhang Gao
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Wenjuan Cao
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Jean-Luc Brédas
- Department of Chemistry and Biochemistry, University of Arizona College of Science, Tucson, AZ, 85721-0088, USA
| | - Veaceslav Coropceanu
- Department of Chemistry and Biochemistry, University of Arizona College of Science, Tucson, AZ, 85721-0088, USA
| | - Feng Li
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
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17
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Wang LH, Zhang KN, Sun M, Li M, Cai XF, Tan Y, Hao XT, Du XY. Reducing Voltage Losses of Organic Solar Cells against Energetics Modifications by Thermal Stress. J Phys Chem Lett 2022; 13:11974-11981. [PMID: 36535016 DOI: 10.1021/acs.jpclett.2c03283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Voltage losses are one of the main obstacles for further improvement in the power conversion efficiency of organic solar cells. In this work, we investigate the effect of thermal stress on voltage losses in various material systems by multiple spectroscopic measurements on both devices and thin films. The energetics of nonfullerene small molecules are more readily altered under thermal stress compared to all-polymer and fullerene-based systems, thereby strongly affecting open-circuit voltage. These energetics variations correlate with the glass transition of respective materials. While nonfullerene small molecular acceptor systems exhibit both dynamic and static disorders which can be restrained in annealed films, all-polymeric systems exhibit dominated static disorders, which are also stable against thermal stress. The much higher voltage losses in fullerene-based systems compared to the other two counterparts are mainly due to the losses from device band gap to charge transfer states and the high nonradiative recombination.
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Affiliation(s)
- Ling-Hua Wang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan250100, P. R. China
| | - Kang-Ning Zhang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan250100, P. R. China
| | - Ming Sun
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan250100, P. R. China
| | - Min Li
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan250100, P. R. China
| | - Xiao-Fan Cai
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan250100, P. R. China
| | - Yang Tan
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan250100, P. R. China
| | - Xiao-Tao Hao
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan250100, P. R. China
- ARC Centre of Excellence in Exciton Science, School of Chemistry, The University of Melbourne, Parkville, Victoria3010, Australia
| | - Xiao-Yan Du
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan250100, P. R. China
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou510640, P. R. China
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18
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Zhang L, Sun R, Zhang Z, Zhang J, Zhu Q, Ma W, Min J, Wei Z, Deng D. Donor End-Capped Alkyl Chain Length Dependent Non-Radiative Energy Loss in All-Small-Molecule Organic Solar Cells. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2207020. [PMID: 36263872 DOI: 10.1002/adma.202207020] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 09/22/2022] [Indexed: 06/16/2023]
Abstract
A critical bottleneck for further efficiency breakthroughs in organic solar cells (OSCs) is to minimize the non-radiative energy loss (eΔVnr ) while maximizing the charge generation. With the development of highly emissive low-bandgap non-fullerene acceptors, the design of high-performance donors becomes critical to enable the blend with the electroluminescence quantum efficiency to approach or surpass the pristine acceptor. Herein, by shortening the end-capped alkyl chains of the small-molecular donors from hexyl (MPhS-C6) to ethyl (MPhS-C2), the material obtained aggregation that was insensitive to thermal annealing (TA) along with condensed packing simultaneously. The former leads to small phase separation and suppressed upshifts of the highest occupied molecular orbital energy level during TA, and the latter facilitates its efficient charge-transport at aggregation-less packing. Hence, the ΔVnr decreases from 0.242 to 0.182 V, from MPhS-C6 to MPhS-C2 based OSCs. An excellent PCE of 17.11% is obtained by 1,8-diiodoctane addition due to almost unchanged high Jsc (26.6 mA cm-2 ) and Voc (0.888 V) with improved fill factor, which is the record efficiency with the smallest energy loss (0.497 eV) and ΔVnr (0.192 V) in all-small-molecule OSCs. These results emphasize the potential material design direction of obtaining concurrent TA-insensitive aggregation and condensed packing to maximize the device performances with a super low ΔVnr .
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Affiliation(s)
- Lili Zhang
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
- Sino-Danish Center for Education and Research, Sino-Danish College, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Rui Sun
- The Institute for Advanced Studies, Wuhan University, Wuhan, 430072, P. R. China
| | - Ziqi Zhang
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
| | - Jianqi Zhang
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
| | - Qinglian Zhu
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, P. R. China
| | - Wei Ma
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, P. R. China
| | - Jie Min
- The Institute for Advanced Studies, Wuhan University, Wuhan, 430072, P. R. China
| | - Zhixiang Wei
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
| | - Dan Deng
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
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19
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Andermann AM, Rego LGC. Quantum Mechanical Assessment of Optimal Photovoltaic Conditions in Organic Solar Cells. J Phys Chem Lett 2022; 13:11001-11007. [PMID: 36404620 DOI: 10.1021/acs.jpclett.2c02622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Recombination losses contribute to reducing JSC, VOC, and the fill factor of organic solar cells. Recent advances in non-fullerene organic photovoltaics have shown, nonetheless, that efficient charge generation can occur under small energetic driving forces (ΔEDA) and low recombination losses. To shed light on this issue, we set up a coarse-grained open quantum mechanical model for investigating the charge generation dynamics subject to various energy loss mechanisms. The influences of energetic driving force, Coulomb interaction, vibrational disorder, geminate recombination, temperature, and external bias are included in the analysis of the optimal photovoltaic conditions for charge carrier generation. The assessment reveals that the overall energy losses are not only minimized when ΔEDA approaches the effective reorganization energy at the interface but also become insensitive to temperature and electric field variations. It is also observed that a moderate reverse bias reduces geminate recombination losses significantly at vanishing driving forces, where the charge generation is strongly affected by temperature.
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Affiliation(s)
- Artur M Andermann
- Department of Physics, Universidade Federal de Santa Catarina, 88040-900, Florianópolis, Santa Catarina, Brazil
| | - Luis G C Rego
- Department of Physics, Universidade Federal de Santa Catarina, 88040-900, Florianópolis, Santa Catarina, Brazil
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20
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Wei Z, Philip AM, Jager WF, Grozema FC. Fast Charge Separation in Distant Donor-Acceptor Dyads Driven by Relaxation of a Hot Excited State. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2022; 126:19250-19261. [PMID: 36424999 PMCID: PMC9677426 DOI: 10.1021/acs.jpcc.2c05754] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 09/26/2022] [Indexed: 06/16/2023]
Abstract
A series of three perylenemonoimide-p-oligophenylene-dimethylaniline molecular dyads undergo photoinduced charge separation (CS) with anomalous distance dependence as a function of increasing donor-acceptor (DA) distances. A comprehensive experimental and computational investigation of the photodynamics in the donor-bridge-acceptor (DBA) chromophores reveals a clear demarcation concerning the nature of the CS accessed at shorter (bridgeless) and longer DA distances. At the shortest distance, a strong DA interaction and ground-state charge delocalization populate a hot excited state (ES) with prominent charge transfer (CT) character, via Franck-Condon vertical excitation. The presence of such a CT-polarized hot ES enables a subpicosecond CS in the bridgeless dyad. The incorporation of the p-oligophenylene bridge effectively decouples the donor and the acceptor units in the ground state and consequentially suppresses the CT polarization in the hot ES. Theoretically, this should render a slower CS at longer distances. However, the transient absorption measurement reveals a fast CS process at the longer distance, contrary to the anticipated exponential distance dependence of the CS rates. A closer look into the excited-state dynamics suggests that the hot ES undergoes ultrafast geometry relaxation (τ < 1 ps) to create a relaxed ES. As compared to a decoupled, twisted geometry in the hot ES, the geometry of the relaxed ES exhibits a more planar conformation of the p-oligophenylene bridges. Planarization of the bridge endorses an increased charge delocalization and a prominent CT character in the relaxed ES and forms the origin for the evident fast CS at the longest distance. Thus, the relaxation of the hot ES and the concomitantly enhanced charge delocalization adds a new caveat to the classic nature of distance-dependent CS in artificial DBA chromophores and recommends a cautious treatment of the attenuation factor (β) while discussing anomalous CS trends.
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21
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Green JA, Gómez S, Worth G, Santoro F, Improta R. Solvent Effects on Ultrafast Charge Transfer Population: Insights from the Quantum Dynamics of Guanine-Cytosine in Chloroform. Chemistry 2022; 28:e202201731. [PMID: 35950519 PMCID: PMC9828530 DOI: 10.1002/chem.202201731] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Indexed: 01/12/2023]
Abstract
We study the ultrafast photoactivated dynamics of the hydrogen bonded dimer Guanine-Cytosine in chloroform solution, focusing on the population of the Guanine→Cytosine charge transfer state (GC-CT), an important elementary process for the photophysics and photochemistry of nucleic acids. We integrate a quantum dynamics propagation scheme, based on a linear vibronic model parameterized through time dependent density functional theory calculations, with four different solvation models, either implicit or explicit. On average, after 50 fs, 30∼40 % of the bright excited state population has been transferred to GC-CT. This process is thus fast and effective, especially when transferring from the Guanine bright excited states, in line with the available experimental studies. Independent of the adopted solvation model, the population of GC-CT is however disfavoured in solution with respect to the gas phase. We show that dynamical solvation effects are responsible for this puzzling result and assess the different chemical-physical effects modulating the population of CT states on the ultrafast time-scale. We also propose some simple analyses to predict how solvent can affect the population transfer between bright and CT states, showing that the effect of the solute/solvent electrostatic interactions on the energy of the CT state can provide a rather reliable indication of its possible population.
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Affiliation(s)
- James A. Green
- Istituto di Biostrutture e Bioimmagini-CNRVia De Amicis 95I-80145Napoli
| | - Sandra Gómez
- Department of ChemistryUniversity College London20 Gordon StreetLondonWC1H 0AJUnited Kingdom,Departamento de Química FísicaUniversity of SalamancaSalamanca37008Spain
| | - Graham Worth
- Department of ChemistryUniversity College London20 Gordon StreetLondonWC1H 0AJUnited Kingdom
| | - Fabrizio Santoro
- Istituto di Chimica die Composti Organometallici (ICCOM-CNR), Area della Ricerca del CNRVia Moruzzi 1I-56124Pisa
| | - Roberto Improta
- Istituto di Biostrutture e Bioimmagini-CNRVia De Amicis 95I-80145Napoli
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22
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Gao J, Yu N, Chen Z, Wei Y, Li C, Liu T, Gu X, Zhang J, Wei Z, Tang Z, Hao X, Zhang F, Zhang X, Huang H. Over 19.2% Efficiency of Organic Solar Cells Enabled by Precisely Tuning the Charge Transfer State Via Donor Alloy Strategy. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2203606. [PMID: 35999345 PMCID: PMC9596821 DOI: 10.1002/advs.202203606] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 07/12/2022] [Indexed: 05/29/2023]
Abstract
The large energy loss (Eloss ) is one of the main obstacles to further improve the photovoltaic performance of organic solar cells (OSCs), which is closely related to the charge transfer (CT) state. Herein, ternary donor alloy strategy is used to precisely tune the energy of CT state (ECT ) and thus the Eloss for boosting the efficiency of OSCs. The elevated ECT in the ternary OSCs reduce the energy loss for charge generation (ΔECT ), and promote the hybridization between localized excitation state and CT state to reduce the nonradiative energy loss (ΔEnonrad ). Together with the optimal morphology, the ternary OSCs afford an impressive power conversion efficiency of 19.22% with a significantly improved open-circuit voltage (Voc ) of 0.910 V without sacrificing short-cicuit density (Jsc ) and fill factor (FF) in comparison to the binary ones. This contribution reveals that precisely tuning the ECT via donor alloy strategy is an efficient way to minimize Eloss and improve the photovoltaic performance of OSCs.
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Affiliation(s)
- Jinhua Gao
- College of Materials Science and Opto‐Electronic TechnologyCenter of Materials Science and Optoelectronics EngineeringCAS Center for Excellence in Topological Quantum ComputationCAS Key Laboratory of Vacuum PhysicUniversity of Chinese Academy of SciencesBeijing100049China
| | - Na Yu
- Center for Advanced Low‐Dimension MaterialsState Key Laboratory for Modification of Chemical Fibers and Polymer MaterialsCollege of Materials Science and EngineeringDonghua UniversityShanghai201620China
| | - Zhihao Chen
- School of PhysicsState Key Laboratory of Crystal MaterialsShandong UniversityJinanShandong250100China
| | - Yanan Wei
- College of Materials Science and Opto‐Electronic TechnologyCenter of Materials Science and Optoelectronics EngineeringCAS Center for Excellence in Topological Quantum ComputationCAS Key Laboratory of Vacuum PhysicUniversity of Chinese Academy of SciencesBeijing100049China
| | - Congqi Li
- College of Materials Science and Opto‐Electronic TechnologyCenter of Materials Science and Optoelectronics EngineeringCAS Center for Excellence in Topological Quantum ComputationCAS Key Laboratory of Vacuum PhysicUniversity of Chinese Academy of SciencesBeijing100049China
| | - Tianhua Liu
- College of Materials Science and Opto‐Electronic TechnologyCenter of Materials Science and Optoelectronics EngineeringCAS Center for Excellence in Topological Quantum ComputationCAS Key Laboratory of Vacuum PhysicUniversity of Chinese Academy of SciencesBeijing100049China
| | - Xiaobin Gu
- College of Materials Science and Opto‐Electronic TechnologyCenter of Materials Science and Optoelectronics EngineeringCAS Center for Excellence in Topological Quantum ComputationCAS Key Laboratory of Vacuum PhysicUniversity of Chinese Academy of SciencesBeijing100049China
| | - Jianqi Zhang
- Center for Excellence in Nanoscience (CAS)Key Laboratory of Nanosystem and Hierarchical Fabrication (CAS)National Center for Nanoscience and TechnologyBeijing100190China
| | - Zhixiang Wei
- Center for Excellence in Nanoscience (CAS)Key Laboratory of Nanosystem and Hierarchical Fabrication (CAS)National Center for Nanoscience and TechnologyBeijing100190China
| | - Zheng Tang
- Center for Advanced Low‐Dimension MaterialsState Key Laboratory for Modification of Chemical Fibers and Polymer MaterialsCollege of Materials Science and EngineeringDonghua UniversityShanghai201620China
| | - Xiaotao Hao
- School of PhysicsState Key Laboratory of Crystal MaterialsShandong UniversityJinanShandong250100China
| | - Fujun Zhang
- Key Laboratory of Luminescence and Optical InformationMinistry of EducationBeijing Jiaotong UniversityBeijing100044China
| | - Xin Zhang
- College of Materials Science and Opto‐Electronic TechnologyCenter of Materials Science and Optoelectronics EngineeringCAS Center for Excellence in Topological Quantum ComputationCAS Key Laboratory of Vacuum PhysicUniversity of Chinese Academy of SciencesBeijing100049China
| | - Hui Huang
- College of Materials Science and Opto‐Electronic TechnologyCenter of Materials Science and Optoelectronics EngineeringCAS Center for Excellence in Topological Quantum ComputationCAS Key Laboratory of Vacuum PhysicUniversity of Chinese Academy of SciencesBeijing100049China
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23
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Peng WT, Brey D, Giannini S, Dell’Angelo D, Burghardt I, Blumberger J. Exciton Dissociation in a Model Organic Interface: Excitonic State-Based Surface Hopping versus Multiconfigurational Time-Dependent Hartree. J Phys Chem Lett 2022; 13:7105-7112. [PMID: 35900333 PMCID: PMC9376959 DOI: 10.1021/acs.jpclett.2c01928] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 07/19/2022] [Indexed: 05/20/2023]
Abstract
Quantum dynamical simulations are essential for a molecular-level understanding of light-induced processes in optoelectronic materials, but they tend to be computationally demanding. We introduce an efficient mixed quantum-classical nonadiabatic molecular dynamics method termed eXcitonic state-based Surface Hopping (X-SH), which propagates the electronic Schrödinger equation in the space of local excitonic and charge-transfer electronic states, coupled to the thermal motion of the nuclear degrees of freedom. The method is applied to exciton decay in a 1D model of a fullerene-oligothiophene junction, and the results are compared to the ones from a fully quantum dynamical treatment at the level of the Multilayer Multiconfigurational Time-Dependent Hartree (ML-MCTDH) approach. Both methods predict that charge-separated states are formed on the 10-100 fs time scale via multiple "hot-exciton dissociation" pathways. The results demonstrate that X-SH is a promising tool advancing the simulation of photoexcited processes from the molecular to the true nanomaterials scale.
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Affiliation(s)
- Wei-Tao Peng
- Department
of Physics and Astronomy and Thomas Young Centre, University College London, London WC1E 6BT, United Kingdom
| | - Dominik Brey
- Institute
of Physical and Theoretical Chemistry, Goethe
University Frankfurt, Max-von-Laue-Strasse 7, 60438 Frankfurt am Main, Germany
| | - Samuele Giannini
- Department
of Physics and Astronomy and Thomas Young Centre, University College London, London WC1E 6BT, United Kingdom
| | - David Dell’Angelo
- Department
of Physics and Astronomy and Thomas Young Centre, University College London, London WC1E 6BT, United Kingdom
| | - Irene Burghardt
- Institute
of Physical and Theoretical Chemistry, Goethe
University Frankfurt, Max-von-Laue-Strasse 7, 60438 Frankfurt am Main, Germany
| | - Jochen Blumberger
- Department
of Physics and Astronomy and Thomas Young Centre, University College London, London WC1E 6BT, United Kingdom
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24
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Zhang G, Lin FR, Qi F, Heumüller T, Distler A, Egelhaaf HJ, Li N, Chow PCY, Brabec CJ, Jen AKY, Yip HL. Renewed Prospects for Organic Photovoltaics. Chem Rev 2022; 122:14180-14274. [PMID: 35929847 DOI: 10.1021/acs.chemrev.1c00955] [Citation(s) in RCA: 120] [Impact Index Per Article: 60.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Organic photovoltaics (OPVs) have progressed steadily through three stages of photoactive materials development: (i) use of poly(3-hexylthiophene) and fullerene-based acceptors (FAs) for optimizing bulk heterojunctions; (ii) development of new donors to better match with FAs; (iii) development of non-fullerene acceptors (NFAs). The development and application of NFAs with an A-D-A configuration (where A = acceptor and D = donor) has enabled devices to have efficient charge generation and small energy losses (Eloss < 0.6 eV), resulting in substantially higher power conversion efficiencies (PCEs) than FA-based devices. The discovery of Y6-type acceptors (Y6 = 2,2'-((2Z,2'Z)-((12,13-bis(2-ethylhexyl)-3,9-diundecyl-12,13-dihydro-[1,2,5]-thiadiazolo[3,4-e]-thieno[2″,3″:4',5']thieno-[2',3':4,5]pyrrolo-[3,2-g]thieno-[2',3':4,5]thieno-[3,2-b]indole-2,10-diyl)bis(methanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile) with an A-DA' D-A configuration has further propelled the PCEs to go beyond 15% due to smaller Eloss values (∼0.5 eV) and higher external quantum efficiencies. Subsequently, the PCEs of Y6-series single-junction devices have increased to >19% and may soon approach 20%. This review provides an update of recent progress of OPV in the following aspects: developments of novel NFAs and donors, understanding of the structure-property relationships and underlying mechanisms of state-of-the-art OPVs, and tasks underpinning the commercialization of OPVs, such as device stability, module development, potential applications, and high-throughput manufacturing. Finally, an outlook and prospects section summarizes the remaining challenges for the further development of OPV technology.
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Affiliation(s)
- Guichuan Zhang
- State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China.,School of Semiconductor Science and Technology, South China Normal University, Foshan 528225, China
| | - Francis R Lin
- Department of Materials Science and Engineering, City University of Hong Kong, Kowloon 999077, Hong Kong, China.,Department of Chemistry, City University of Hong Kong, Kowloon 999077, Hong Kong, China
| | - Feng Qi
- Department of Materials Science and Engineering, City University of Hong Kong, Kowloon 999077, Hong Kong, China.,Department of Chemistry, City University of Hong Kong, Kowloon 999077, Hong Kong, China
| | - Thomas Heumüller
- Institute of Materials for Electronics and Energy Technology (i-MEET), Department of Materials Science and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstrasse 7, 91058 Erlangen, Germany.,Helmholtz Institute Erlangen-Nürnberg (HI ERN), Immerwahrstrasse 2, 91058 Erlangen, Germany
| | - Andreas Distler
- Institute of Materials for Electronics and Energy Technology (i-MEET), Department of Materials Science and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstrasse 7, 91058 Erlangen, Germany
| | - Hans-Joachim Egelhaaf
- Institute of Materials for Electronics and Energy Technology (i-MEET), Department of Materials Science and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstrasse 7, 91058 Erlangen, Germany.,Helmholtz Institute Erlangen-Nürnberg (HI ERN), Immerwahrstrasse 2, 91058 Erlangen, Germany
| | - Ning Li
- State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China
| | - Philip C Y Chow
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam 999077, Hong Kong, China
| | - Christoph J Brabec
- Institute of Materials for Electronics and Energy Technology (i-MEET), Department of Materials Science and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstrasse 7, 91058 Erlangen, Germany.,Helmholtz Institute Erlangen-Nürnberg (HI ERN), Immerwahrstrasse 2, 91058 Erlangen, Germany
| | - Alex K-Y Jen
- Department of Materials Science and Engineering, City University of Hong Kong, Kowloon 999077, Hong Kong, China.,Department of Chemistry, City University of Hong Kong, Kowloon 999077, Hong Kong, China.,School of Energy and Environment, City University of Hong Kong, Kowloon 999077, Hong Kong, China.,Hong Kong Institute for Clean Energy, City University of Hong Kong, Kowloon 999077, Hong Kong, China
| | - Hin-Lap Yip
- State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China.,Department of Materials Science and Engineering, City University of Hong Kong, Kowloon 999077, Hong Kong, China.,School of Energy and Environment, City University of Hong Kong, Kowloon 999077, Hong Kong, China.,Hong Kong Institute for Clean Energy, City University of Hong Kong, Kowloon 999077, Hong Kong, China
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25
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Yan J, Rodríguez-Martínez X, Pearce D, Douglas H, Bili D, Azzouzi M, Eisner F, Virbule A, Rezasoltani E, Belova V, Dörling B, Few S, Szumska AA, Hou X, Zhang G, Yip HL, Campoy-Quiles M, Nelson J. Identifying structure-absorption relationships and predicting absorption strength of non-fullerene acceptors for organic photovoltaics. ENERGY & ENVIRONMENTAL SCIENCE 2022; 15:2958-2973. [PMID: 35923416 PMCID: PMC9277517 DOI: 10.1039/d2ee00887d] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 05/20/2022] [Indexed: 06/15/2023]
Abstract
Non-fullerene acceptors (NFAs) are excellent light harvesters, yet the origin of their high optical extinction is not well understood. In this work, we investigate the absorption strength of NFAs by building a database of time-dependent density functional theory (TDDFT) calculations of ∼500 π-conjugated molecules. The calculations are first validated by comparison with experimental measurements in solution and solid state using common fullerene and non-fullerene acceptors. We find that the molar extinction coefficient (ε d,max) shows reasonable agreement between calculation in vacuum and experiment for molecules in solution, highlighting the effectiveness of TDDFT for predicting optical properties of organic π-conjugated molecules. We then perform a statistical analysis based on molecular descriptors to identify which features are important in defining the absorption strength. This allows us to identify structural features that are correlated with high absorption strength in NFAs and could be used to guide molecular design: highly absorbing NFAs should possess a planar, linear, and fully conjugated molecular backbone with highly polarisable heteroatoms. We then exploit a random decision forest algorithm to draw predictions for ε d,max using a computational framework based on extended tight-binding Hamiltonians, which shows reasonable predicting accuracy with lower computational cost than TDDFT. This work provides a general understanding of the relationship between molecular structure and absorption strength in π-conjugated organic molecules, including NFAs, while introducing predictive machine-learning models of low computational cost.
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Affiliation(s)
- Jun Yan
- Department of Physics, Imperial College London SW7 2AZ London UK
| | - Xabier Rodríguez-Martínez
- Electronic and Photonic Materials (EFM), Department of Physics, Chemistry and Biology (IFM), Linköping University Linköping SE 581 83 Sweden
- Instituto de Ciencia de Materiales de Barcelona, ICMAB-CSIC, Campus UAB Bellaterra 08193 Spain
| | - Drew Pearce
- Department of Physics, Imperial College London SW7 2AZ London UK
| | - Hana Douglas
- Department of Physics, Imperial College London SW7 2AZ London UK
| | - Danai Bili
- Department of Physics, Imperial College London SW7 2AZ London UK
| | - Mohammed Azzouzi
- Department of Physics, Imperial College London SW7 2AZ London UK
| | - Flurin Eisner
- Department of Physics, Imperial College London SW7 2AZ London UK
| | - Alise Virbule
- Department of Physics, Imperial College London SW7 2AZ London UK
| | | | - Valentina Belova
- Instituto de Ciencia de Materiales de Barcelona, ICMAB-CSIC, Campus UAB Bellaterra 08193 Spain
| | - Bernhard Dörling
- Instituto de Ciencia de Materiales de Barcelona, ICMAB-CSIC, Campus UAB Bellaterra 08193 Spain
| | - Sheridan Few
- Department of Physics, Imperial College London SW7 2AZ London UK
- Sustainability Research Institute, School of Earth and Environment, University of Leeds LS2 9JT Leeds UK
| | - Anna A Szumska
- Department of Physics, Imperial College London SW7 2AZ London UK
| | - Xueyan Hou
- Department of Physics, Imperial College London SW7 2AZ London UK
| | - Guichuan Zhang
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology Guangzhou 510640 P. R. China
| | - Hin-Lap Yip
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology Guangzhou 510640 P. R. China
- Department of Materials Science and Engineering, City University of Hong Kong, Tat Chee Avenue Kowloon Hong Kong
| | - Mariano Campoy-Quiles
- Instituto de Ciencia de Materiales de Barcelona, ICMAB-CSIC, Campus UAB Bellaterra 08193 Spain
| | - Jenny Nelson
- Department of Physics, Imperial College London SW7 2AZ London UK
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26
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Shivhare R, Moore GJ, Hofacker A, Hutsch S, Zhong Y, Hambsch M, Erdmann T, Kiriy A, Mannsfeld SCB, Ortmann F, Banerji N. Short Excited-State Lifetimes Mediate Charge-Recombination Losses in Organic Solar Cell Blends with Low Charge-Transfer Driving Force. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2101784. [PMID: 34396598 DOI: 10.1002/adma.202101784] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 06/18/2021] [Indexed: 06/13/2023]
Abstract
A blend of a low-optical-gap diketopyrrolopyrrole polymer and a fullerene derivative, with near-zero driving force for electron transfer, is investigated. Using femtosecond transient absorption and electroabsorption spectroscopy, the charge transfer (CT) and recombination dynamics as well as the early-time transport are quantified. Electron transfer is ultrafast, consistent with a Marcus-Levich-Jortner description. However, significant charge recombination and unusually short excited (S1 ) and CT state lifetimes (≈14 ps) are observed. At low S1 -CT offset, a short S1 lifetime mediates charge recombination because: i) back-transfer from the CT to the S1 state followed by S1 recombination occurs and ii) additional S1 -CT hybridization decreases the CT lifetime. Both effects are confirmed by density functional theory calculations. In addition, relatively slow (tens of picoseconds) dissociation of charges from the CT state is observed, due to low local charge mobility. Simulations using a four-state kinetic model entailing the effects of energetic disorder reveal that the free charge yield can be increased from the observed 12% to 60% by increasing the S1 and CT lifetimes to 150 ps. Alternatively, decreasing the interfacial CT state disorder while increasing bulk disorder of free charges enhances the yield to 65% in spite of the short lifetimes.
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Affiliation(s)
- Rishi Shivhare
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, Bern, CH-3012, Switzerland
| | - Gareth John Moore
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, Bern, CH-3012, Switzerland
| | - Andreas Hofacker
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Institute for Applied Physics, Technical University of Dresden, Nöthnitzerstrasse 61, D-01187, Dresden, Germany
| | - Sebastian Hutsch
- Department of Chemistry, Technical University of Munich, Lichtenbergstrasse 4, D-85748, Garching b. München, Germany
- Center for Advancing Electronics Dresden, Technical University of Dresden, Helmholtzstrasse 18, D-01069, Dresden, Germany
| | - Yufei Zhong
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, Bern, CH-3012, Switzerland
| | - Mike Hambsch
- Center for Advancing Electronics Dresden, Technical University of Dresden, Helmholtzstrasse 18, D-01069, Dresden, Germany
| | - Tim Erdmann
- IBM Almaden Research Center, 650 Harry Road, San Jose, CA, 95120, USA
| | - Anton Kiriy
- Leibniz Institute of Polymer Research Dresden, Hohestrasse 6, D-01069, Dresden, Germany
| | - Stefan C B Mannsfeld
- Center for Advancing Electronics Dresden, Technical University of Dresden, Helmholtzstrasse 18, D-01069, Dresden, Germany
| | - Frank Ortmann
- Department of Chemistry, Technical University of Munich, Lichtenbergstrasse 4, D-85748, Garching b. München, Germany
- Center for Advancing Electronics Dresden, Technical University of Dresden, Helmholtzstrasse 18, D-01069, Dresden, Germany
| | - Natalie Banerji
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, Bern, CH-3012, Switzerland
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27
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Kaienburg P, Jungbluth A, Habib I, Kesava SV, Nyman M, Riede MK. Assessing the Photovoltaic Quality of Vacuum-Thermal Evaporated Organic Semiconductor Blends. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2107584. [PMID: 34821418 DOI: 10.1002/adma.202107584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 11/18/2021] [Indexed: 06/13/2023]
Abstract
Vacuum-thermal evaporation (VTE) is a highly relevant fabrication route for organic solar cells (OSCs), especially on an industrial scale as proven by the commercialization of organic light emitting diode-based displays. While OSC performance is reported for a range of VTE-deposited molecules, a comprehensive assessment of donor:acceptor blend properties with respect to their photovoltaic performance is scarce. Here, the organic thin films and solar cells of three select systems are fabricated and ellipsometry, external quantum efficiency with high dynamic range, as well as OTRACE are measured to quantify absorption, voltage losses, and charge carrier mobility. These parameters are key to explain OSC performance and will help to rationalize the performance of other material systems reported in literature as the authors' methodology is applicable beyond VTE systems. Furthermore, it can help to judge the prospects of new molecules in general. The authors find large differences in the measured values and find that today's VTE OSCs can reach high extinction coefficients, but only moderate mobility and voltage loss compared to their solution-processed counterparts. What needs to be improved for VTE OSCs is outlined to again catch up with their solution-processed counterparts in terms of power conversion efficiency.
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Affiliation(s)
- Pascal Kaienburg
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, OX1 3PU, UK
| | - Anna Jungbluth
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, OX1 3PU, UK
| | - Irfan Habib
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, OX1 3PU, UK
| | - Sameer Vajjala Kesava
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, OX1 3PU, UK
| | - Mathias Nyman
- Physics, Faculty of Science and Engineering, Åbo Akademi University, Porthansgatan 3, Turku, 20500, Finland
| | - Moritz K Riede
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, OX1 3PU, UK
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28
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Andermann AM, Rego LGC. Energetics of the charge generation in organic donor-acceptor interfaces. J Chem Phys 2022; 156:024104. [PMID: 35032994 DOI: 10.1063/5.0076611] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Non-fullerene acceptor materials have posed new paradigms for the design of organic solar cells , whereby efficient carrier generation is obtained with small driving forces, in order to maximize the open-circuit voltage (VOC). In this paper, we use a coarse-grained mixed quantum-classical method, which combines Ehrenfest and Redfield theories, to shed light on the charge generation process in small energy offset interfaces. We have investigated the influence of the energetic driving force as well as the vibronic effects on the charge generation and photovoltaic energy conversion. By analyzing the effects of the Holstein and Peierls vibrational couplings, we find that vibrational couplings produce an overall effect of improving the charge generation. However, the two vibronic mechanisms play different roles: the Holstein relaxation mechanism decreases the charge generation, whereas the Peierls mechanism always assists the charge generation. Moreover, by examining the electron-hole binding energy as a function of time, we evince two distinct regimes for the charge separation: the temperature independent excitonic spread on a sub-100 fs timescale and the complete dissociation of the charge-transfer state that occurs on the timescale of tens to hundreds of picoseconds, depending on the temperature. The quantum dynamics of the system exhibits the three regimes of the Marcus electron transfer kinetics as the energy offset of the interface is varied.
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Affiliation(s)
- Artur M Andermann
- Department of Physics, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, Santa Catarina, Brazil
| | - Luis G C Rego
- Department of Physics, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, Santa Catarina, Brazil
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Liu Y, Zheng Z, Coropceanu V, Brédas JL, Ginger DS. Lower limits for non-radiative recombination loss in organic donor/acceptor complexes. MATERIALS HORIZONS 2022; 9:325-333. [PMID: 34842253 DOI: 10.1039/d1mh00529d] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Understanding the factors controlling radiative and non-radiative transition rates for charge transfer states in organic systems is important for applications ranging from organic photovoltaics (OPV) to lasers and LEDs. We explore the role of charge-transfer (CT) energetics, lifetimes, and photovoltaic properties in the limit of very slow non-radiative rates by using a model donor/acceptor system with photoluminescence dominated by thermally activated delayed fluorescence (TADF). This blend exhibits an extremely high photoluminescence quantum efficiency (PLQY = ∼22%) and comparatively long PL lifetime, while simultaneously yielding appreciable amounts of free charge generation (photocurrent external quantum efficiency EQE of 24%). In solar cells, this blend exhibits non-radiative voltage losses of only ∼0.1 V, among the lowest reported for an organic system. Notably, we find that the non-radiative decay rate, knr, is on the order of 105 s-1, approximately 4-5 orders of magnitude slower than typical OPV blends, thereby confirming that high radiative efficiency and low non-radiative voltage losses are achievable by reducing knr. Furthermore, despite the high radiative efficiency and already comparatively slow knr, we find that knr is nevertheless much faster than predicted by Marcus-Levich-Jortner two-state theory and we conclude that CT-local exciton (LE) hybridization is present. Our findings highlight that it is crucial to evaluate how radiative and non-radiative rates of the LE states individually influence the PLQY of charge-transfer states, rather than solely focusing on the PLQY of the LE. This conclusion will guide material selection in achieving low non-radiative voltage loss in organic solar cells and high luminescence efficiency in organic LEDs.
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Affiliation(s)
- Yun Liu
- Department of Chemistry, University of Washington, Seattle, WA, 98195-2120, USA.
| | - Zilong Zheng
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, 30332-0400, USA
- College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China
| | - Veaceslav Coropceanu
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, 30332-0400, USA
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, AZ, 85721-0088, USA
| | - Jean-Luc Brédas
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, 30332-0400, USA
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, AZ, 85721-0088, USA
| | - David S Ginger
- Department of Chemistry, University of Washington, Seattle, WA, 98195-2120, USA.
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Wang J, Jiang X, Wu H, Feng G, Wu H, Li J, Yi Y, Feng X, Ma Z, Li W, Vandewal K, Tang Z. Increasing donor-acceptor spacing for reduced voltage loss in organic solar cells. Nat Commun 2021; 12:6679. [PMID: 34795261 PMCID: PMC8602729 DOI: 10.1038/s41467-021-26995-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 10/26/2021] [Indexed: 11/09/2022] Open
Abstract
The high voltage losses ([Formula: see text]), originating from inevitable electron-phonon coupling in organic materials, limit the power conversion efficiency of organic solar cells to lower values than that of inorganic or perovskite solar cells. In this work, we demonstrate that this [Formula: see text] can in fact be suppressed by controlling the spacing between the donor (D) and the acceptor (A) materials (DA spacing). We show that in typical organic solar cells, the DA spacing is generally too small, being the origin of the too-fast non-radiative decay of charge carriers ([Formula: see text]), and it can be increased by engineering the non-conjugated groups, i.e., alkyl chain spacers in single component DA systems and side chains in high-efficiency bulk-heterojunction systems. Increasing DA spacing allows us to realize significantly reduced [Formula: see text] and improved device voltage. This points out a new research direction for breaking the performance bottleneck of organic solar cells.
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Affiliation(s)
- Jing Wang
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Center for Advanced Low-dimension Materials, College of Materials Science and Engineering, Donghua University, Shanghai, 201620, P. R. China
| | - Xudong Jiang
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering & State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing, 100029, P. R. China
- Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P.R. China
| | - Hongbo Wu
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Center for Advanced Low-dimension Materials, College of Materials Science and Engineering, Donghua University, Shanghai, 201620, P. R. China
| | - Guitao Feng
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering & State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing, 100029, P. R. China
- Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P.R. China
| | - Hanyu Wu
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Center for Advanced Low-dimension Materials, College of Materials Science and Engineering, Donghua University, Shanghai, 201620, P. R. China
| | - Junyu Li
- DSM DMSC R&D Solutions, P.O. Box 18, 6160 MD, Geleen, The Netherlands
| | - Yuanping Yi
- Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P.R. China
| | - Xunda Feng
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Center for Advanced Low-dimension Materials, College of Materials Science and Engineering, Donghua University, Shanghai, 201620, P. R. China
| | - Zaifei Ma
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Center for Advanced Low-dimension Materials, College of Materials Science and Engineering, Donghua University, Shanghai, 201620, P. R. China
| | - Weiwei Li
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering & State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing, 100029, P. R. China.
- Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P.R. China.
| | - Koen Vandewal
- Instituut voor Materiaalonderzoek (IMO-IMOMEC), Hasselt University, Wetenschapspark 1, BE-3590, Diepenbeek, Belgium.
| | - Zheng Tang
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Center for Advanced Low-dimension Materials, College of Materials Science and Engineering, Donghua University, Shanghai, 201620, P. R. China.
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31
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Jeon K, Jen M, Lee S, Jang T, Pang Y. Intramolecular Charge Transfer of 1-Aminoanthraquinone and Ultrafast Solvation Dynamics of Dimethylsulfoxide. Int J Mol Sci 2021; 22:ijms222111926. [PMID: 34769357 PMCID: PMC8584543 DOI: 10.3390/ijms222111926] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/29/2021] [Accepted: 11/01/2021] [Indexed: 11/16/2022] Open
Abstract
The intramolecular charge transfer (ICT) of 1-aminoanthraquinone (AAQ) in the excited state strongly depends on its solvent properties, and the twisted geometry of its amino group has been recommended for the twisted ICT (TICT) state by recent theoretical works. We report the transient Raman spectra of AAQ in a dimethylsulfoxide (DMSO) solution by femtosecond stimulated Raman spectroscopy to provide clear experimental evidence for the TICT state of AAQ. The ultrafast (~110 fs) TICT dynamics of AAQ were observed from the major vibrational modes of AAQ including the νC-N + δCH and νC=O modes. The coherent oscillations in the vibrational bands of AAQ strongly coupled to the nuclear coordinate for the TICT process have been observed, which showed its anharmonic coupling to the low frequency out of the plane deformation modes. The vibrational mode of solvent DMSO, νS=O showed a decrease in intensity, especially in the hydrogen-bonded species of DMSO, which clearly shows that the solvation dynamics of DMSO, including hydrogen bonding, are crucial to understanding the reaction dynamics of AAQ with the ultrafast structural changes accompanying the TICT.
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Hong L, Yao H, Cui Y, Bi P, Zhang T, Cheng Y, Zu Y, Qin J, Yu R, Ge Z, Hou J. 18.5% Efficiency Organic Solar Cells with a Hybrid Planar/Bulk Heterojunction. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2103091. [PMID: 34510580 DOI: 10.1002/adma.202103091] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 08/17/2021] [Indexed: 06/13/2023]
Abstract
The donor:acceptor heterojunction has proved as the most successful approach to split strongly bound excitons in organic solar cells (OSCs). Establishing an ideal architecture with selective carrier transport and suppressed recombination is of great importance to improve the photovoltaic efficiency while remains a challenge. Herein, via tailoring a hybrid planar/bulk structure, highly efficient OSCs with reduced energy losses (Eloss s) are fabricated. A p-type benzodithiophene-thiophene alternating polymer and an n-type naphthalene imide are inserted on both sides of a mixed donor:acceptor active layer to construct the hybrid heterojunction, respectively. The tailored structure with the donor near the anode and the acceptor near the cathode is beneficial for obtaining enhanced charge transport, extraction, and suppressed charge recombination. As a result, the photovoltaic characterizations suggest a reduced nonradiative Eloss by 25 meV, and the best OSC records a high efficiency of 18.5% (certified as 18.2%). This study highlights that precisely regulating the structure of donor:acceptor heterojunction has the potential to further improve the efficiencies of OSCs.
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Affiliation(s)
- Ling Hong
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China
| | - Huifeng Yao
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Yong Cui
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Pengqing Bi
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Tao Zhang
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Yongxin Cheng
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Yunfei Zu
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Jinzhao Qin
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Runnan Yu
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, P. R. China
| | - Ziyi Ge
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China
| | - Jianhui Hou
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
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33
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The role of charge recombination to triplet excitons in organic solar cells. Nature 2021; 597:666-671. [PMID: 34588666 DOI: 10.1038/s41586-021-03840-5] [Citation(s) in RCA: 106] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 07/20/2021] [Indexed: 11/08/2022]
Abstract
The use of non-fullerene acceptors (NFAs) in organic solar cells has led to power conversion efficiencies as high as 18%1. However, organic solar cells are still less efficient than inorganic solar cells, which typically have power conversion efficiencies of more than 20%2. A key reason for this difference is that organic solar cells have low open-circuit voltages relative to their optical bandgaps3, owing to non-radiative recombination4. For organic solar cells to compete with inorganic solar cells in terms of efficiency, non-radiative loss pathways must be identified and suppressed. Here we show that in most organic solar cells that use NFAs, the majority of charge recombination under open-circuit conditions proceeds via the formation of non-emissive NFA triplet excitons; in the benchmark PM6:Y6 blend5, this fraction reaches 90%, reducing the open-circuit voltage by 60 mV. We prevent recombination via this non-radiative channel by engineering substantial hybridization between the NFA triplet excitons and the spin-triplet charge-transfer excitons. Modelling suggests that the rate of back charge transfer from spin-triplet charge-transfer excitons to molecular triplet excitons may be reduced by an order of magnitude, enabling re-dissociation of the spin-triplet charge-transfer exciton. We demonstrate NFA systems in which the formation of triplet excitons is suppressed. This work thus provides a design pathway for organic solar cells with power conversion efficiencies of 20% or more.
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34
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Deperasińska I, Banasiewicz M, Gawryś P, Morawski O, Olas J, Kozankiewicz B. Spectra and nature of the electronic states of [1]Benzothieno[3,2-b][1]benzothiophene (BTBT): Single crystal and the aggregates. J Chem Phys 2021; 155:034504. [PMID: 34293905 DOI: 10.1063/5.0057202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Absorption, fluorescence, and phosphorescence spectra of single crystals of [1]benzothieno[3,2-b][1]benzothiophene (BTBT) and BTBT dispersed in frozen n-nonane, n-hexadecane, and dichloromethane matrices were studied at 5 K. Observation of a new absorption band and related changes in the fluorescence to phosphorescence intensity ratio, when the concentration of BTBT in the matrix increased above 10-4M, indicated the presence of BTBT aggregates. Quantum-chemistry calculations performed for the simplest aggregate, isolated dimer, showed that its structure is similar to the "herringbone" element in the BTBT crystal unit cell and the lowest electronic excited singlet state of the dimer has the intermolecular charge-transfer character. A qualitatively different nature of this state in dimers and in crystals, when compared with the situation in BTBT monomer [locally excited (LE) state], is associated with a decrease in the intersystem crossing yield. The structured vibronic structure of phosphorescence spectra in the studied systems indicated LE character of the triplet states.
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Affiliation(s)
- Irena Deperasińska
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | - Marzena Banasiewicz
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | - Paweł Gawryś
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | - Olaf Morawski
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | - Joanna Olas
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | - Boleslaw Kozankiewicz
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
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Ma L, Yao H, Wang J, Xu Y, Gao M, Zu Y, Cui Y, Zhang S, Ye L, Hou J. Impact of Electrostatic Interaction on Bulk Morphology in Efficient Donor-Acceptor Photovoltaic Blends. Angew Chem Int Ed Engl 2021; 60:15988-15994. [PMID: 33932274 DOI: 10.1002/anie.202102622] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Indexed: 11/10/2022]
Abstract
Bulk heterojunctions comprising mixed donor (D) and acceptor (A) materials have proven to be the most efficient device structures for organic photovoltaic (OPV) cells. The bulk morphology of such cells plays a key role in charge generation, recombination, and transport, thus determining the device performance. Although numerous studies have discussed the morphology-performance relationship of these cells, the method of designing OPV materials with the desired morphology remains unclear. Herein, guided by molecular electrostatic potential distributions, we have established a connection between the chemical structure and bulk morphology. We show that the molecular orientation at the D-A interface and the domain purity in the blend can be effectively modulated by modifying the functional groups. Enhancing the D-A interaction is beneficial for charge generation. However, the resulting low domain purity and increased charge transfer ratio in its hybridization with the local excitation states lead to severe charge recombination. Fine-tuning the bulk morphology can give balanced charge generation and recombination, which is crucial for further boosting the efficiency of the OPV cells.
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Affiliation(s)
- Lijiao Ma
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China.,University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Huifeng Yao
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Jingwen Wang
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China.,University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Ye Xu
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China.,University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Mengyuan Gao
- School of Materials Science and Engineering, Tianjin University, Tianjin, 300350, P. R. China
| | - Yunfei Zu
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China.,University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Yong Cui
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Shaoqing Zhang
- School of Chemistry and Biology Engineering, University of Science and Technology Beijing, Beijing, 100083, P. R. China
| | - Long Ye
- School of Materials Science and Engineering, Tianjin University, Tianjin, 300350, P. R. China.,State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Jianhui Hou
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China.,University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
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Ma L, Yao H, Wang J, Xu Y, Gao M, Zu Y, Cui Y, Zhang S, Ye L, Hou J. Impact of Electrostatic Interaction on Bulk Morphology in Efficient Donor–Acceptor Photovoltaic Blends. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202102622] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Lijiao Ma
- Beijing National Laboratory for Molecular Sciences State Key Laboratory of Polymer Physics and Chemistry CAS Research/Education Center for Excellence in Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
| | - Huifeng Yao
- Beijing National Laboratory for Molecular Sciences State Key Laboratory of Polymer Physics and Chemistry CAS Research/Education Center for Excellence in Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
| | - Jingwen Wang
- Beijing National Laboratory for Molecular Sciences State Key Laboratory of Polymer Physics and Chemistry CAS Research/Education Center for Excellence in Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
| | - Ye Xu
- Beijing National Laboratory for Molecular Sciences State Key Laboratory of Polymer Physics and Chemistry CAS Research/Education Center for Excellence in Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
| | - Mengyuan Gao
- School of Materials Science and Engineering Tianjin University Tianjin 300350 P. R. China
| | - Yunfei Zu
- Beijing National Laboratory for Molecular Sciences State Key Laboratory of Polymer Physics and Chemistry CAS Research/Education Center for Excellence in Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
| | - Yong Cui
- Beijing National Laboratory for Molecular Sciences State Key Laboratory of Polymer Physics and Chemistry CAS Research/Education Center for Excellence in Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
| | - Shaoqing Zhang
- School of Chemistry and Biology Engineering University of Science and Technology Beijing Beijing 100083 P. R. China
| | - Long Ye
- School of Materials Science and Engineering Tianjin University Tianjin 300350 P. R. China
- State Key Laboratory of Luminescent Materials and Devices South China University of Technology Guangzhou 510640 P. R. China
| | - Jianhui Hou
- Beijing National Laboratory for Molecular Sciences State Key Laboratory of Polymer Physics and Chemistry CAS Research/Education Center for Excellence in Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
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DFT and TD-DFT Investigation of a Charge Transfer Surface Resonance Raman Model of N3 Dye Bound to a Small TiO 2 Nanoparticle. NANOMATERIALS 2021; 11:nano11061491. [PMID: 34199980 PMCID: PMC8226483 DOI: 10.3390/nano11061491] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 05/28/2021] [Accepted: 05/28/2021] [Indexed: 12/02/2022]
Abstract
Raman spectroscopy is an important method for studying the configuration of Ru bipyridyl dyes on TiO2. We studied the [Ru(II)(4,4′-COOH-2,2′-bpy)2(NCS)2)] dye (N3) adsorbed on a (TiO2)5 nanoparticle using Density Functional Theory, DFT, to optimize the geometry of the complex and to simulate normal Raman scattering, NRS, for the isolated N3 and the N3–(TiO2)5 complex. Two configurations of N3 are found on the surface both anchored with a carboxylate bridging bidentate linkage but one with the two NCS ligands directed away from the surface and one with one NSC tilted away and the other NCS interacting with the surface. Both configurations also had another –COOH group hydrogen bonded to a Ti-O dangling bond. These configurations can be distinguished from each other by Raman bands at 2104 and 2165 cm−1. The former configuration has more intense Normal Raman Scattering, NRS, on TiO2 surfaces and was studied with Time-Dependent Density Functional Theory, TD-DFT, frequency-dependent Raman simulations. Pre-resonance Raman spectra were simulated for a Metal to Ligand Charge Transfer, MLCT, excited state and for a long-distance CT transition from N3 directly to (TiO2)5. Enhancement factors for the MLCT and long-distance CT processes are around 1 × 103 and 2 × 102, respectively. A Herzberg–Teller intensity borrowing mechanism is implicated in the latter and provides a possible mechanism for the photo-injection of electrons to titania surfaces.
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Xu Z, Zhou Y, Yam CY, Groß L, De Sio A, Frauenheim T, Lienau C, Chen G. Revealing generation, migration, and dissociation of electron-hole pairs and current emergence in an organic photovoltaic cell. SCIENCE ADVANCES 2021; 7:eabf7672. [PMID: 34144986 PMCID: PMC8213226 DOI: 10.1126/sciadv.abf7672] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Accepted: 05/05/2021] [Indexed: 05/13/2023]
Abstract
Using an innovative quantum mechanical method for an open quantum system, we observe in real time and space the generation, migration, and dissociation of electron-hole pairs, transport of electrons and holes, and current emergence in an organic photovoltaic cell. Ehrenfest dynamics is used to study photoexcitation of thiophene:fullerene stacks coupled with a time-dependent density functional tight-binding method. Our results display the generation of an electron-hole pair in the donor and its subsequent migration to the donor-acceptor interface. At the interface, electrons transfer from the lowest unoccupied molecular orbitals (LUMOs) of thiophenes to the second LUMOs of fullerene. Further migration of electrons and holes leads to the emergence of current. These findings support previous experimental evidence of coherent couplings between electronic and vibrational degrees of freedom and are expected to stimulate further work toward exploring the interplay between electron-hole pair (exciton) binding and vibronic coupling for charge separation and transport.
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Affiliation(s)
- Ziyao Xu
- Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - Yi Zhou
- Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - Chi Yung Yam
- Shenzhen JL Computational Science and Applied Research Institute, Shenzhen 518110, China
- Beijing Computational Science Research Center, Beijing 100084, China
| | - Lynn Groß
- Bremen Center for Computational Materials Science, University of Bremen, Am Fallturm 1, 28359 Bremen, Germany
| | - Antonietta De Sio
- Institut für Physik and Center of Interface Science, Carl von Ossietzky Universität, Oldenburg 26129, Germany
| | - Thomas Frauenheim
- Shenzhen JL Computational Science and Applied Research Institute, Shenzhen 518110, China
- Beijing Computational Science Research Center, Beijing 100084, China
- Bremen Center for Computational Materials Science, University of Bremen, Am Fallturm 1, 28359 Bremen, Germany
| | - Christoph Lienau
- Institut für Physik and Center of Interface Science, Carl von Ossietzky Universität, Oldenburg 26129, Germany
| | - Guanhua Chen
- Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong SAR, China.
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39
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Shaikh J, Congrave DG, Forster A, Minotto A, Cacialli F, Hele TJH, Penfold TJ, Bronstein H, Clarke TM. Intrinsic photogeneration of long-lived charges in a donor-orthogonal acceptor conjugated polymer. Chem Sci 2021; 12:8165-8177. [PMID: 34194707 PMCID: PMC8208312 DOI: 10.1039/d1sc00919b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 05/08/2021] [Indexed: 11/21/2022] Open
Abstract
Efficient charge photogeneration in conjugated polymers typically requires the presence of a second component to act as electron acceptor. Here, we report a novel low band-gap conjugated polymer with a donor/orthogonal acceptor motif: poly-2,6-(4,4-dihexadecyl-4H-cyclopenta [2,1-b:3,4-b']dithiophene)-alt-2,6-spiro [cyclopenta[2,1-b:3,4-b']dithiophene-4,9'-fluorene]-2',7'-dicarbonitrile, referred to as PCPDT-sFCN. The role of the orthogonal acceptor is to spatially isolate the LUMO from the HOMO, allowing for negligible exchange energy between electrons in these orbitals and minimising the energy gap between singlet and triplet charge transfer states. We employ ultrafast and microsecond transient absorption spectroscopy to demonstrate that, even in the absence of a separate electron acceptor, PCPDT-sFCN shows efficient charge photogeneration in both pristine solution and film. This efficient charge generation is a result of an isoenergetic singlet/triplet charge transfer state equilibrium acting as a reservoir for charge carrier formation. Furthermore, clear evidence of enhanced triplet populations, which form in less than 1 ps, is observed. Using group theory, we show that this ultrafast triplet formation is due to highly efficient, quantum mechanically allowed intersystem crossing between the bright, initially photoexcited local singlet state and the triplet charge transfer state. Remarkably, the free charges that form via the charge transfer state are extraordinarily long-lived with millisecond lifetimes, possibly due to the stabilisation imparted by the spatial separation of PCPDT-sFCN's donor and orthogonal acceptor motifs. The efficient generation of long-lived charge carriers in a pristine polymer paves the way for single-material applications such as organic photovoltaics and photodetectors.
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Affiliation(s)
- Jordan Shaikh
- Department of Chemistry, University College London Christopher Ingold Building London WC1H 0AJ UK
| | - Daniel G Congrave
- Department of Chemistry, University of Cambridge Lensfield Road Cambridge CB2 1EW UK
| | - Alex Forster
- Department of Chemistry, University of Cambridge Lensfield Road Cambridge CB2 1EW UK
| | - Alessandro Minotto
- Department of Physics, University College London Gower Street London WC1E 6BT UK
| | - Franco Cacialli
- Department of Physics, University College London Gower Street London WC1E 6BT UK
| | - Timothy J H Hele
- Department of Chemistry, University College London Christopher Ingold Building London WC1H 0AJ UK
| | - Thomas J Penfold
- Chemistry - School of Natural and Environmental Sciences, Newcastle University Newcastle upon Tyne NE1 7RU UK
| | - Hugo Bronstein
- Department of Chemistry, University of Cambridge Lensfield Road Cambridge CB2 1EW UK
| | - Tracey M Clarke
- Department of Chemistry, University College London Christopher Ingold Building London WC1H 0AJ UK
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40
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Park SH, Kwon NY, Kim HJ, Cho E, Kang H, Harit AK, Woo HY, Yoon HJ, Cho MJ, Choi DH. Nonhalogenated Solvent-Processed High-Performance Indoor Photovoltaics Made of New Conjugated Terpolymers with Optimized Monomer Compositions. ACS APPLIED MATERIALS & INTERFACES 2021; 13:13487-13498. [PMID: 33710873 DOI: 10.1021/acsami.0c22946] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Conjugated random terpolymers, PJ-25, PJ-50, and PJ-75 were successfully synthesized from three different monomers. Fluorine-substituted benzotriazole (2F-BTA) was incorporated into 4,8-bis(4-chlorothiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene (BDT-T-Cl) and a 1,3-bis(4-(2-ethylhexyl)thiophen-2-yl)-5,7-bis(2-alkyl)benzo[1,2-c:4,5-c']dithiophene-4,8-dione (BDD)-based alternating copolymer PM7 as a third monomeric unit. The solubility of the random terpolymers in nonhalogenated solvents increased with the number of 2F-BTA units in PM7. The random terpolymers were mixed with 3,9-bis(2-methylene-((3-(1,1-dicyanomethylene)-6,7-difluoro)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2',3'-d']-s-indaceno[1,2-b:5,6-b']dithiophene (IT-4F) to fabricate organic photovoltaic (OPV) cells. Among the three terpolymers and two related binary copolymers (e.g., PM7 and J52-Cl), outdoor photovoltaic (PV) cells (AM 1.5G) based on the PJ-50:IT-4F blend showed a high power conversion efficiency (PCE) of 11.34%. In addition, PJ-50 was employed as a donor in indoor PV (IPV) cells and was blended with nonfullerene acceptors, which have different absorption ranges. Among them, the PJ-50:IT-4F-based IPV device had the highest PCE of 17.41% with a Jsc of 54.75 μA cm-2 and an FF of 0.77 under 160 μW cm-2 light-emitting diode (LED) light. The terpolymer introduced in this study can be regarded as a promising material for the fabrication of outdoor PV and IPV cells with excellent performance involving the use of an eco-friendly solvent.
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Affiliation(s)
- Su Hong Park
- Department of Chemistry, Research Institute for Natural Sciences, Korea University, 145 Anam-Ro, Sungbuk-gu, Seoul 02841, Republic of Korea
| | - Na Yeon Kwon
- Department of Chemistry, Research Institute for Natural Sciences, Korea University, 145 Anam-Ro, Sungbuk-gu, Seoul 02841, Republic of Korea
| | - Hyung Jong Kim
- Department of Chemistry, Research Institute for Natural Sciences, Korea University, 145 Anam-Ro, Sungbuk-gu, Seoul 02841, Republic of Korea
| | - Eunbin Cho
- Department of Chemistry, Research Institute for Natural Sciences, Korea University, 145 Anam-Ro, Sungbuk-gu, Seoul 02841, Republic of Korea
| | - Hungu Kang
- Department of Chemistry, Research Institute for Natural Sciences, Korea University, 145 Anam-Ro, Sungbuk-gu, Seoul 02841, Republic of Korea
| | - Amit Kumar Harit
- Department of Chemistry, Research Institute for Natural Sciences, Korea University, 145 Anam-Ro, Sungbuk-gu, Seoul 02841, Republic of Korea
| | - Han Young Woo
- Department of Chemistry, Research Institute for Natural Sciences, Korea University, 145 Anam-Ro, Sungbuk-gu, Seoul 02841, Republic of Korea
| | - Hyo Jae Yoon
- Department of Chemistry, Research Institute for Natural Sciences, Korea University, 145 Anam-Ro, Sungbuk-gu, Seoul 02841, Republic of Korea
| | - Min Ju Cho
- Department of Chemistry, Research Institute for Natural Sciences, Korea University, 145 Anam-Ro, Sungbuk-gu, Seoul 02841, Republic of Korea
| | - Dong Hoon Choi
- Department of Chemistry, Research Institute for Natural Sciences, Korea University, 145 Anam-Ro, Sungbuk-gu, Seoul 02841, Republic of Korea
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41
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Adjusting the energy of interfacial states in organic photovoltaics for maximum efficiency. Nat Commun 2021; 12:1772. [PMID: 33741966 PMCID: PMC7979693 DOI: 10.1038/s41467-021-22032-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 02/22/2021] [Indexed: 11/09/2022] Open
Abstract
A critical bottleneck for improving the performance of organic solar cells (OSC) is minimising non-radiative losses in the interfacial charge-transfer (CT) state via the formation of hybrid energetic states. This requires small energetic offsets often detrimental for high external quantum efficiency (EQE). Here, we obtain OSC with both non-radiative voltage losses (0.24 V) and photocurrent losses (EQE > 80%) simultaneously minimised. The interfacial CT states separate into free carriers with ≈40-ps time constant. We combine device and spectroscopic data to model the thermodynamics of charge separation and extraction, revealing that the relatively high performance of the devices arises from an optimal adjustment of the CT state energy, which determines how the available overall driving force is efficiently used to maximize both exciton splitting and charge separation. The model proposed is universal for donor:acceptor (D:A) with low driving forces and predicts which D:A will benefit from a morphology optimization for highly efficient OSC.
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42
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Cainelli M, Tanimura Y. Exciton transfer in organic photovoltaic cells: A role of local and nonlocal electron–phonon interactions in a donor domain. J Chem Phys 2021; 154:034107. [DOI: 10.1063/5.0036590] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Mauro Cainelli
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Yoshitaka Tanimura
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
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43
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Schwarz KN, Mitchell VD, Khan SUZ, Lee C, Reinhold A, Smith TA, Ghiggino KP, Jones DJ, Rand BP, Scholes GD. Morphological Requirements for Nanoscale Electric Field Buildup in a Bulk Heterojunction Solar Cell. J Phys Chem Lett 2021; 12:537-545. [PMID: 33378206 DOI: 10.1021/acs.jpclett.0c03425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The morphology of organic semiconductors is critical to their function in optoelectronic devices and is particularly crucial in the donor-acceptor mixture that comprises the bulk heterojunction of organic solar cells. Here, energy landscapes can play integral roles in charge photogeneration, and recently have been shown to drive the accumulation of charge carriers away from the interface, resulting in the buildup of large nanoscale electric fields, much like a capacitor. In this work we combine morphological and spectroscopic data to outline the requirements for this interdomain charge accumulation, finding that this effect is driven by a three-phase morphology that creates an energetic cascade for charge carriers. By adjusting annealing conditions, we show that domain purity, but not size, is critical for an electro-absorption feature to grow-in. This demonstrates that the energy landscape around the interface shapes the movement of charges and that pure domains are required for charge carrier buildup that results in reduced recombination and large interdomain nanoscale electric fields.
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Affiliation(s)
- Kyra N Schwarz
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Valerie D Mitchell
- Australian Synchrotron, 800 Blackburn Road, Clayton, VIC 3168, Australia
| | | | | | - Adam Reinhold
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | | | | | | | | | - Gregory D Scholes
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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44
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Marmolejo-Valencia AF, Mata-Pinzón Z, Amador-Bedolla C. Charge-transfer electronic states in organic solar cells: a TDDFT study. Phys Chem Chem Phys 2021; 23:16806-16815. [PMID: 34323261 DOI: 10.1039/d1cp00723h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The prediction of new organic photovoltaic materials in organic solar cells (OSCs) must include a precise description of charge-transfer states because they are involved in electron-transfer processes such as charge separation and charge recombination which govern the device efficiency. Also, as the experimental performance of an optoelectronic device is measured for nonequilibrium nanostructures, computational approaches need models that can incorporate morphology effects. Usually, this aspect is treated by molecular dynamics simulation (MDS) methodologies; however, methodologies and formalisms to calculate the electron-transfer processes are still controversial and sometimes do not connect their information with the phase morphologies. In this work we propose a simple and fast characterization of electron-transfer processes to find the rate constants by analysing the distribution of vertical excitation energies of both local excitation (LE) and charge-transfer (CT) states using TD-DFT calculations in the donor-acceptor pair structures which were extracted from MDS. This proposal assumes that conformational changes are prevented and equilibria are not achieved while the electron-transfer events take effect, and thus the only pathway that connects the LE and CT states is their surface crossing point where an ideal distribution might exist. Different density functionals and dialectric models were tested. The results indicate a close relationship between the proposal and experimental data for electron-transfer events, suggesting the application of this method in the rational design of new photovoltaic materials.
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Affiliation(s)
- Andres F Marmolejo-Valencia
- Facultad de Química, Universidad Nacional Autónoma de México, Av. Universidad 3000, Coyoacán, CDMX 04510, Mexico.
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45
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Park SW, Yang JH, Choi H, Rhee YM, Kim D. Effect of Perturbative Vibronic Correction for Weak Fluorescence in Thermally Activated Delayed Fluorescence Systems. J Phys Chem A 2020; 124:10384-10392. [PMID: 33245236 DOI: 10.1021/acs.jpca.0c09439] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Minimizing the energy difference between the lowest singlet (S1) and the lowest triplet states, ΔEST, is the main strategy to design thermally activated delayed fluorescence (TADF) molecules, and spatially separating the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) is the general method in the design. However, such a separation also tends to reduce the oscillator strength of the S1 state. In real systems, vibrations change the S1 oscillator strength, and thus one needs to consider the vibronic coupling toward searching for TADF candidate molecules. Here, we evaluate the importance of vibronic coupling by including the first-order perturbative correction to the transition dipole moments of carbazolyl-phthalonitrile derivatives. Indeed, some molecules display large enhancements in their oscillator strengths, with their fluorescence lifetimes reduced by 2 orders of magnitude. The twisting mode between the carbazole groups and phthalonitrile is the most important mode in inducing the perturbations. Thus, performing the perturbative correction is crucial in attaining more reliable predictions on their fluorescence propensities. We also observe that some other molecules, whose zeroth-order predicted fluorescence rates are much slower than the actual experimental data, are affected little by the same first-order correction. For these molecules, we deduce that the geometry-dependent excited-state switching kicks in. Our results demonstrate the significance of vibronic coupling in TADF molecules and the importance of adopting correction schemes as the guidelines for screening of useful TADF molecules.
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Affiliation(s)
- Soo Wan Park
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Joong Hwan Yang
- OC Research, LG Display, LG Science Park, 30, Magokjungang 10-ro, Gangseo-gu, Seoul 07796, Korea
| | - Hyongjong Choi
- OC Research, LG Display, LG Science Park, 30, Magokjungang 10-ro, Gangseo-gu, Seoul 07796, Korea
| | - Young Min Rhee
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Dongwook Kim
- Department of Chemistry, Kyonggi University, Suwon 16227, Korea
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46
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Xu G, Rao H, Liao X, Zhang Y, Wang Y, Xing Z, Hu T, Tan L, Chen L, Chen Y. Reducing Energy Loss and Morphology Optimization Manipulated by Molecular Geometry Engineering for Hetero‐junction Organic Solar Cells. CHINESE J CHEM 2020. [DOI: 10.1002/cjoc.202000235] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Guodong Xu
- College of Chemistry/Institute of Polymers and Energy Chemistry (IPEC), Nanchang University Nanchang Jiangxi 330031 China
- Department of Physics Chemistry and Biology (IFM), Linköping University Linköping SE‐581 83 Sweden
| | - Huan Rao
- College of Chemistry/Institute of Polymers and Energy Chemistry (IPEC), Nanchang University Nanchang Jiangxi 330031 China
| | - Xunfan Liao
- Institute of Advanced Scientific Research (iASR), Jiangxi Normal University 99 Ziyang Avenue Nanchang Jiangxi 330022 China
| | - Youdi Zhang
- College of Chemistry/Institute of Polymers and Energy Chemistry (IPEC), Nanchang University Nanchang Jiangxi 330031 China
| | - Yuming Wang
- Department of Physics Chemistry and Biology (IFM), Linköping University Linköping SE‐581 83 Sweden
| | - Zhi Xing
- College of Chemistry/Institute of Polymers and Energy Chemistry (IPEC), Nanchang University Nanchang Jiangxi 330031 China
| | - Ting Hu
- College of Chemistry/Institute of Polymers and Energy Chemistry (IPEC), Nanchang University Nanchang Jiangxi 330031 China
| | - Licheng Tan
- College of Chemistry/Institute of Polymers and Energy Chemistry (IPEC), Nanchang University Nanchang Jiangxi 330031 China
| | - Lie Chen
- College of Chemistry/Institute of Polymers and Energy Chemistry (IPEC), Nanchang University Nanchang Jiangxi 330031 China
| | - Yiwang Chen
- College of Chemistry/Institute of Polymers and Energy Chemistry (IPEC), Nanchang University Nanchang Jiangxi 330031 China
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47
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Hinrichsen TF, Chan CCS, Ma C, Paleček D, Gillett A, Chen S, Zou X, Zhang G, Yip HL, Wong KS, Friend RH, Yan H, Rao A, Chow PCY. Long-lived and disorder-free charge transfer states enable endothermic charge separation in efficient non-fullerene organic solar cells. Nat Commun 2020; 11:5617. [PMID: 33154367 PMCID: PMC7645751 DOI: 10.1038/s41467-020-19332-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 09/28/2020] [Indexed: 11/17/2022] Open
Abstract
Organic solar cells based on non-fullerene acceptors can show high charge generation yields despite near-zero donor–acceptor energy offsets to drive charge separation and overcome the mutual Coulomb attraction between electron and hole. Here, we use time-resolved optical spectroscopy to show that free charges in these systems are generated by thermally activated dissociation of interfacial charge-transfer states that occurs over hundreds of picoseconds at room temperature, three orders of magnitude slower than comparable fullerene-based systems. Upon free electron–hole encounters at later times, both charge-transfer states and emissive excitons are regenerated, thus setting up an equilibrium between excitons, charge-transfer states and free charges. Our results suggest that the formation of long-lived and disorder-free charge-transfer states in these systems enables them to operate closely to quasi-thermodynamic conditions with no requirement for energy offsets to drive interfacial charge separation and achieve suppressed non-radiative recombination. Designing efficient organic solar cells is limited by the energy required to overcome the mutual Coulomb attraction between electron and hole. Here, the authors reveal long-lived and disorder-free charge-transfer states enable efficient endothermic charge separation in non-fullerene systems with marginal energy offset.
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Affiliation(s)
- Ture F Hinrichsen
- Cavendish Laboratory, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Christopher C S Chan
- Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay,, Hong Kong, China
| | - Chao Ma
- Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay,, Hong Kong, China
| | - David Paleček
- Cavendish Laboratory, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Alexander Gillett
- Cavendish Laboratory, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Shangshang Chen
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay,, Hong Kong, China
| | - Xinhui Zou
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay,, Hong Kong, China
| | - Guichuan Zhang
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, China
| | - Hin-Lap Yip
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, China
| | - Kam Sing Wong
- Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay,, Hong Kong, China
| | - Richard H Friend
- Cavendish Laboratory, University of Cambridge, Cambridge, CB3 0HE, UK.
| | - He Yan
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay,, Hong Kong, China.
| | - Akshay Rao
- Cavendish Laboratory, University of Cambridge, Cambridge, CB3 0HE, UK.
| | - Philip C Y Chow
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay,, Hong Kong, China. .,Department of Mechanical Engineering, The University of Hong Kong, Pokfulam, Hong Kong, China.
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48
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An N, Cai Y, Wu H, Tang A, Zhang K, Hao X, Ma Z, Guo Q, Ryu HS, Woo HY, Sun Y, Zhou E. Solution-Processed Organic Solar Cells with High Open-Circuit Voltage of 1.3 V and Low Non-Radiative Voltage Loss of 0.16 V. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2002122. [PMID: 32844465 DOI: 10.1002/adma.202002122] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 07/16/2020] [Indexed: 06/11/2023]
Abstract
Compared with inorganic or perovskite solar cells, the relatively large non-radiative recombination voltage losses (ΔVnon-rad ) in organic solar cells (OSCs) limit the improvement of the open-circuit voltage (Voc ). Herein, OSCs are fabricated by adopting two pairs of D-π-A polymers (PBT1-C/PBT1-C-2Cl and PBDB-T/PBDB-T-2Cl) as electron donors and a wide-bandgap molecule BTA3 as the electron acceptor. In these blends, a charge-transfer state energy (ECT ) as high as 1.70-1.76 eV is achieved, leading to small energetic differences between the singlet excited states and charge-transfer states (ΔECT ≈ 0.1 eV). In addition, after introducing chlorine atoms into the π-bridge or the side chain of benzodithiophene (BDT) unit, electroluminescence external quantum efficiencies as high as 1.9 × 10-3 and 1.0 × 10-3 are realized in OSCs based on PBTI-C-2Cl and PBDB-T-2Cl, respectively. Their corresponding ΔVnon-rad are 0.16 and 0.17 V, which are lower than those of OSCs based on the analog polymers without a chlorine atom (0.21 and 0.24 V for PBT1-C and PBDB-T, respectively), resulting in high Voc of 1.3 V. The ΔVnon-rad of 0.16 V and Voc of 1.3 V achieved in PBT1-C-2Cl:BTA3 OSCs are thought to represent the best values for solution-processed OSCs reported in the literature so far.
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Affiliation(s)
- Ning An
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China
| | - Yunhao Cai
- School of Chemistry, Beihang University, Beijing, 100191, China
| | - Hongbo Wu
- Center for Advanced Low-Dimension Materials, State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, Shanghai, 201620, China
| | - Ailing Tang
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China
| | - Kangning Zhang
- School of Physics State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, China
| | - Xiaotao Hao
- School of Physics State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, China
| | - Zaifei Ma
- Center for Advanced Low-Dimension Materials, State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, Shanghai, 201620, China
| | - Qiang Guo
- Henan Institute of Advanced Technology, Zhengzhou University, Zhengzhou, 450003, China
| | - Hwa Sook Ryu
- Department of Chemistry, College of Scyience, Korea University, Seoul, 136-713, Republic of Korea
| | - Han Young Woo
- Department of Chemistry, College of Scyience, Korea University, Seoul, 136-713, Republic of Korea
| | - Yanming Sun
- School of Chemistry, Beihang University, Beijing, 100191, China
| | - Erjun Zhou
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China
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49
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Sun H, Yu H, Shi Y, Yu J, Peng Z, Zhang X, Liu B, Wang J, Singh R, Lee J, Li Y, Wei Z, Liao Q, Kan Z, Ye L, Yan H, Gao F, Guo X. A Narrow-Bandgap n-Type Polymer with an Acceptor-Acceptor Backbone Enabling Efficient All-Polymer Solar Cells. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2004183. [PMID: 32954584 DOI: 10.1002/adma.202004183] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 07/30/2020] [Indexed: 05/26/2023]
Abstract
Narrow-bandgap polymer semiconductors are essential for advancing the development of organic solar cells. Here, a new narrow-bandgap polymer acceptor L14, featuring an acceptor-acceptor (A-A) type backbone, is synthesized by copolymerizing a dibrominated fused-ring electron acceptor (FREA) with distannylated bithiophene imide. Combining the advantages of both the FREA and the A-A polymer, L14 not only shows a narrow bandgap and high absorption coefficient, but also low-lying frontier molecular orbital (FMO) levels. Such FMO levels yield improved electron transfer character, but unexpectedly, without sacrificing open-circuit voltage (Voc ), which is attributed to a small nonradiative recombination loss (Eloss,nr ) of 0.22 eV. Benefiting from the improved photocurrent along with the high fill factor and Voc , an excellent efficiency of 14.3% is achieved, which is among the highest values for all-polymer solar cells (all-PSCs). The results demonstrate the superiority of narrow-bandgap A-A type polymers for improving all-PSC performance and pave a way toward developing high-performance polymer acceptors for all-PSCs.
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Affiliation(s)
- Huiliang Sun
- Department of Materials Science and Engineering, Southern University of Science and Technology (SUSTech), No. 1088, Xueyuan Road, Shenzhen, Guangdong, 518055, P. R. China
- Department of Chemistry and Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration & Reconstruction, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong, P. R. China
| | - Han Yu
- Department of Chemistry and Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration & Reconstruction, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong, P. R. China
| | - Yongqiang Shi
- Department of Materials Science and Engineering, Southern University of Science and Technology (SUSTech), No. 1088, Xueyuan Road, Shenzhen, Guangdong, 518055, P. R. China
| | - Jianwei Yu
- Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, SE-58183, Sweden
| | - Zhongxiang Peng
- School of Materials Science and Engineering, Tianjin Key Laboratory of Molecular Optoelectronic Science, Tianjin University, Tianjin, 300350, P. R. China
| | - Xianhe Zhang
- Department of Materials Science and Engineering, Southern University of Science and Technology (SUSTech), No. 1088, Xueyuan Road, Shenzhen, Guangdong, 518055, P. R. China
| | - Bin Liu
- Department of Materials Science and Engineering, Southern University of Science and Technology (SUSTech), No. 1088, Xueyuan Road, Shenzhen, Guangdong, 518055, P. R. China
| | - Junwei Wang
- Department of Materials Science and Engineering, Southern University of Science and Technology (SUSTech), No. 1088, Xueyuan Road, Shenzhen, Guangdong, 518055, P. R. China
| | - Ranbir Singh
- Department of Energy & Materials Engineering, Dongguk University, Seoul, 100-715, Republic of Korea
| | - Jaewon Lee
- Department of Chemical Engineering and Applied Chemistry, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Yongchun Li
- Department of Materials Science and Engineering, Southern University of Science and Technology (SUSTech), No. 1088, Xueyuan Road, Shenzhen, Guangdong, 518055, P. R. China
| | - Zixiang Wei
- Department of Materials Science and Engineering, Southern University of Science and Technology (SUSTech), No. 1088, Xueyuan Road, Shenzhen, Guangdong, 518055, P. R. China
| | - Qiaogan Liao
- Department of Materials Science and Engineering, Southern University of Science and Technology (SUSTech), No. 1088, Xueyuan Road, Shenzhen, Guangdong, 518055, P. R. China
| | - Zhipeng Kan
- Chongqing Institute of Green and Intelligent Technology, Chongqing School, University of Chinese Academy of Sciences (UCAS Chongqing), Chinese Academy of Sciences, Chongqing, 400714, P. R. China
| | - Long Ye
- School of Materials Science and Engineering, Tianjin Key Laboratory of Molecular Optoelectronic Science, Tianjin University, Tianjin, 300350, P. R. China
| | - He Yan
- Department of Chemistry and Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration & Reconstruction, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong, P. R. China
| | - Feng Gao
- Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, SE-58183, Sweden
| | - Xugang Guo
- Department of Materials Science and Engineering, Southern University of Science and Technology (SUSTech), No. 1088, Xueyuan Road, Shenzhen, Guangdong, 518055, P. R. China
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Cho E, Coropceanu V, Brédas JL. Organic Neutral Radical Emitters: Impact of Chemical Substitution and Electronic-State Hybridization on the Luminescence Properties. J Am Chem Soc 2020; 142:17782-17786. [DOI: 10.1021/jacs.0c08997] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Eunkyung Cho
- Department of Chemistry and Biochemistry The University of Arizona, Tucson, Arizona 85721-0088, United States
| | - Veaceslav Coropceanu
- Department of Chemistry and Biochemistry The University of Arizona, Tucson, Arizona 85721-0088, United States
| | - Jean-Luc Brédas
- Department of Chemistry and Biochemistry The University of Arizona, Tucson, Arizona 85721-0088, United States
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