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Go E, Jin H, Yoon S, Ahn H, Kim J, Lim C, Kim JH, Din HU, Lee JH, Jun Y, Yu H, Son HJ. Spectrally Resolved Exciton Polarizability for Understanding Charge Generation in Organic Bulk Hetero-Junction Diodes. J Am Chem Soc 2024; 146:14724-14733. [PMID: 38757532 DOI: 10.1021/jacs.4c02361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2024]
Abstract
Despite decades of research, the dominant charge generation mechanism in organic bulk heterojunction (BHJ) devices is not completely understood. While the local dielectric environments of the photoexcited molecules are important for exciton dissociation, conventional characterizations cannot separately measure the polarizability of electron-donor and electron-acceptor, respectively, in their blends, making it difficult to decipher the spectrally different charge generation efficiencies in organic BHJ devices. Here, by spectrally resolved electroabsorption spectroscopy, we report extraction of the excited state polarizability for individual donors and acceptors in a series of organic blend films. Regardless of the donor and acceptor, we discovered that larger exciton polarizability is linked to larger π-π coherence length and faster charge transfer across the heterojunction, which fundamentally explains the origin of the higher charge generation efficiency near 100% in the BHJ photodiodes. We also show that the molecular packing of the donor and acceptor influence each other, resulting in a synergetic enhancement in the exciton polarizability.
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Affiliation(s)
- Enoch Go
- Advanced Photovoltaics Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
- Graduate School of Energy and Environment (KU-KIST GREEN SCHOOL), Korea University, Seoul 02841, Republic of Korea
| | - Hyunjung Jin
- Advanced Photovoltaics Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
- Graduate School of Energy and Environment (KU-KIST GREEN SCHOOL), Korea University, Seoul 02841, Republic of Korea
| | - Seongwon Yoon
- Advanced Photovoltaics Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Hyungju Ahn
- Pohang Accelerator Laboratory, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Joonsoo Kim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Chanwoo Lim
- Advanced Photovoltaics Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Ji-Hee Kim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Department of Physics, Pusan National University, Busan 46241, Republic of Korea
| | - Haleem Ud Din
- Computational Science Research Center, KIST, Seoul 02792, Republic of Korea
| | - Jung-Hoon Lee
- Computational Science Research Center, KIST, Seoul 02792, Republic of Korea
| | - Yongseok Jun
- Graduate School of Energy and Environment (KU-KIST GREEN SCHOOL), Korea University, Seoul 02841, Republic of Korea
| | - Hyeonggeun Yu
- Advanced Photovoltaics Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
- Nanoscience and Technology, KIST School, University of Science and Technology, Seoul 02792, Republic of Korea
| | - Hae Jung Son
- Advanced Photovoltaics Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
- Graduate School of Energy and Environment (KU-KIST GREEN SCHOOL), Korea University, Seoul 02841, Republic of Korea
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Lu G, Shen Z, Wang H, Bu L, Lu G. Optical interference on the measurement of film-depth-dependent light absorption spectroscopy and a correction approach. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2023; 94:023907. [PMID: 36859049 DOI: 10.1063/5.0138336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Accepted: 01/28/2023] [Indexed: 06/18/2023]
Abstract
Organic thin films usually feature vertical phase segregation, and film-depth-dependent light absorption spectroscopy is an emerging characterization method to study the vertical phase separation of active layer films in organic electronics field. However, the interference effects on thin films can lead to optical errors in their characterization results. In this work, the interference effects on fluctuations of peak intensity and peak position of film-depth-dependent light absorption spectroscopy are investigated. Subsequently, a numerical method based on inverse transfer matrix is proposed to obtain the optical constants of the active layer through the film-depth-dependent light absorption spectroscopy. The extinction coefficient error in the non-absorbing wavelength range caused by interference effect is reduced by ∼95% compared with the traditional film-depth-dependent light absorption spectroscopy measurement. Thus, the optical properties of the thin film and quantitative spectrographic analysis based on these optical constants largely avoid the effects of interference including fluctuations of peak intensity and peak position. It is concluded that for many morphologically homogenously films, the spatial (film-depth) resolution of this film-depth-dependent light absorption spectroscopy can be optimized to be <1 nm. Subsequently, this modified film-depth-dependent light absorption spectroscopy approach is employed to simulate the local optical properties within devices with a multilayer architecture.
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Affiliation(s)
- Guanyu Lu
- Frontier Institute of Science and Technology, State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an 710054, China
| | - Zichao Shen
- Frontier Institute of Science and Technology, State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an 710054, China
| | - Hong Wang
- Frontier Institute of Science and Technology, State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an 710054, China
| | - Laju Bu
- School of Chemistry, Xi'an Jiaotong University, Xi'an 710049, China
| | - Guanghao Lu
- Frontier Institute of Science and Technology, State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an 710054, China
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Meng H, Liao C, Deng M, Xu X, Yu L, Peng Q. 18.77 % Efficiency Organic Solar Cells Promoted by Aqueous Solution Processed Cobalt(II) Acetate Hole Transporting Layer. Angew Chem Int Ed Engl 2021; 60:22554-22561. [PMID: 34418267 DOI: 10.1002/anie.202110550] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Indexed: 11/05/2022]
Abstract
A robust hole transporting layer (HTL), using the cost-effective Cobalt(II) acetate tetrahydrate (Co(OAc)2 ⋅4 H2 O) as the precursor, was simply processed from its aqueous solution followed by thermal annealing (TA) and UV-ozone (UVO) treatments. The TA treatment induced the loss of crystal water followed by oxidization of Co(OAc)2 ⋅4 H2 O precursor, which increased the work function. However, TA treatment differently realize a high work function and ideal morphology for charge extraction. The resulting problems could be circumvented easily by additional UVO treatment, which also enhanced the conductivity and lowered the resistance for charge transport. The optimal condition was found to be a low temperature TA (150 °C) followed by simple UVO, where the crystal water in Co(OAc)2 ⋅4 H2 O was removed fully and the HTL surface was anchored by substantial hydroxy groups. Using PM6 as the polymer donor and L8-BO as the electron acceptor, a record high PCE of 18.77 % of the binary blend OSCs was achieved, higher than the common PEDOT:PSS-based solar cell devices (18.02 %).
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Affiliation(s)
- Huifeng Meng
- School of Chemical Engineering, Key Laboratory of Green Chemistry and Technology of Ministry of Education and State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, P. R. China
| | - Chentong Liao
- School of Chemical Engineering, Key Laboratory of Green Chemistry and Technology of Ministry of Education and State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, P. R. China
| | - Min Deng
- School of Chemical Engineering, Key Laboratory of Green Chemistry and Technology of Ministry of Education and State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, P. R. China
| | - Xiaopeng Xu
- School of Chemical Engineering, Key Laboratory of Green Chemistry and Technology of Ministry of Education and State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, P. R. China
| | - Liyang Yu
- School of Chemical Engineering, Key Laboratory of Green Chemistry and Technology of Ministry of Education and State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, P. R. China
| | - Qiang Peng
- School of Chemical Engineering, Key Laboratory of Green Chemistry and Technology of Ministry of Education and State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, P. R. China
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Meng H, Liao C, Deng M, Xu X, Yu L, Peng Q. 18.77 % Efficiency Organic Solar Cells Promoted by Aqueous Solution Processed Cobalt(II) Acetate Hole Transporting Layer. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202110550] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Huifeng Meng
- School of Chemical Engineering Key Laboratory of Green Chemistry and Technology of Ministry of Education and State Key Laboratory of Polymer Materials Engineering Sichuan University Chengdu 610065 P. R. China
| | - Chentong Liao
- School of Chemical Engineering Key Laboratory of Green Chemistry and Technology of Ministry of Education and State Key Laboratory of Polymer Materials Engineering Sichuan University Chengdu 610065 P. R. China
| | - Min Deng
- School of Chemical Engineering Key Laboratory of Green Chemistry and Technology of Ministry of Education and State Key Laboratory of Polymer Materials Engineering Sichuan University Chengdu 610065 P. R. China
| | - Xiaopeng Xu
- School of Chemical Engineering Key Laboratory of Green Chemistry and Technology of Ministry of Education and State Key Laboratory of Polymer Materials Engineering Sichuan University Chengdu 610065 P. R. China
| | - Liyang Yu
- School of Chemical Engineering Key Laboratory of Green Chemistry and Technology of Ministry of Education and State Key Laboratory of Polymer Materials Engineering Sichuan University Chengdu 610065 P. R. China
| | - Qiang Peng
- School of Chemical Engineering Key Laboratory of Green Chemistry and Technology of Ministry of Education and State Key Laboratory of Polymer Materials Engineering Sichuan University Chengdu 610065 P. R. China
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Duan L, Uddin A. Progress in Stability of Organic Solar Cells. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:1903259. [PMID: 32537401 PMCID: PMC7284215 DOI: 10.1002/advs.201903259] [Citation(s) in RCA: 104] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 01/07/2020] [Accepted: 03/25/2020] [Indexed: 05/06/2023]
Abstract
The organic solar cell (OSC) is a promising emerging low-cost thin film photovoltaics technology. The power conversion efficiency (PCE) of OSCs has overpassed 16% for single junction and 17% for organic-organic tandem solar cells with the development of low bandgap organic materials synthesis and device processing technology. The main barrier of commercial use of OSCs is the poor stability of devices. Herein, the factors limiting the stability of OSCs are summarized. The limiting stability factors are oxygen, water, irradiation, heating, metastable morphology, diffusion of electrodes and buffer layers materials, and mechanical stress. The recent progress in strategies to increase the stability of OSCs is surveyed, such as material design, device engineering of active layers, employing inverted geometry, optimizing buffer layers, using stable electrodes and encapsulation materials. The International Summit on Organic Photovoltaic Stability guidelines are also discussed. The potential research strategies to achieve the required device stability and efficiency are highlighted, rendering possible pathways to facilitate the viable commercialization of OSCs.
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Affiliation(s)
- Leiping Duan
- School of Photovoltaic and Renewable Energy EngineeringUniversity of New South WalesSydneyNSW2052Australia
| | - Ashraf Uddin
- School of Photovoltaic and Renewable Energy EngineeringUniversity of New South WalesSydneyNSW2052Australia
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Gurney RS, Lidzey DG, Wang T. A review of non-fullerene polymer solar cells: from device physics to morphology control. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2019; 82:036601. [PMID: 30731432 DOI: 10.1088/1361-6633/ab0530] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The rise in power conversion efficiency of organic photovoltaic (OPV) devices over the last few years has been driven by the emergence of new organic semiconductors and the growing understanding of morphological control at both the molecular and aggregation scales. Non-fullerene OPVs adopting p-type conjugated polymers as the donor and n-type small molecules as the acceptor have exhibited steady progress, outperforming PCBM-based solar cells and reaching efficiencies of over 15% in 2019. This review starts with a refreshed discussion of charge separation, recombination, and V OC loss in non-fullerene OPVs, followed by a review of work undertaken to develop favorable molecular configurations required for high device performance. We summarize several key approaches that have been employed to tune the nanoscale morphology in non-fullerene photovoltaic blends, comparing them (where appropriate) to their PCBM-based counterparts. In particular, we discuss issues ranging from materials chemistry to solution processing and post-treatments, showing how this can lead to enhanced photovoltaic properties. Particular attention is given to the control of molecular configuration through solution processing, which can have a pronounced impact on the structure of the solid-state photoactive layer. Key challenges, including green solvent processing, stability and lifetime, burn-in, and thickness-dependence in non-fullerene OPVs are briefly discussed.
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Affiliation(s)
- Robert S Gurney
- School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, People's Republic of China
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Wang C, Bai Y, Guo Q, Zhao C, Zhang J, Hu S, Hayat T, Alsaedi A, Tan Z. Enhancing charge transport in an organic photoactive layer via vertical component engineering for efficient perovskite/organic integrated solar cells. NANOSCALE 2019; 11:4035-4043. [PMID: 30768110 DOI: 10.1039/c8nr09467e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Suitable vertical component distribution within an organic bulk-heterojunction (BHJ) is vital for effective exciton dissociation and smooth charge transport in perovskite/organic integrated solar cells (ISCs). Herein, a bi-continuous interpenetrating network of organic donor/acceptor materials is constructed simply by optimizing their weight ratio, and is further applied in perovskite/organic ISCs. Time-of-flight secondary-ion mass spectroscopy (TOF-SIMS) and scanning Kelvin probe microscopy (SKPM) strongly confirm that this method can effectively restrict vertical stratification and build a desired bi-continuous framework within the organic photoactive layer, which can effectively suppress two potential recombination losses from the viewpoint of kinetics, leading to the PCE increasing from 12.63% to 15.47% for ISCs based on the structure of MAPbI3/PBDB-T : IEICO. Meanwhile, our ISCs combining a UV-vis harvesting layer of MAPbI3 and a near-infrared absorbing layer of PBDB-T : IEICO exhibit a photo-response extending to the whole visible and infrared spectrum (up to 900 nm). This work verifies that tuning the donor/acceptor weight ratio is a feasible strategy for optimizing the morphology of BHJ absorbers and suppressing charge recombination for efficient perovskite/BHJ ISCs.
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Affiliation(s)
- Chenyun Wang
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China.
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Effect of the incorporation of an Ag nanoparticle interlayer on the photovoltaic performance of green bulk heterojunction water-soluble polythiophene solar cells. POLYMER 2018. [DOI: 10.1016/j.polymer.2018.07.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Xu B, Sai-Anand G, Gopalan AI, Qiao Q, Kang SW. Improving Photovoltaic Properties of P3HT:IC 60BA through the Incorporation of Small Molecules. Polymers (Basel) 2018; 10:E121. [PMID: 30966157 PMCID: PMC6415164 DOI: 10.3390/polym10020121] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 01/22/2018] [Accepted: 01/24/2018] [Indexed: 11/19/2022] Open
Abstract
We investigated the role of a functional solid additive, 2,3-dihydroxypyridine (DHP), in influencing the optoelectronic, morphological, structural and photovoltaic properties of bulk-heterojunction-based polymer solar cells (BHJ PSCs) fabricated using poly(3-hexylthiophene): indene-C60 bisadduct (P3HT:IC60BA) photoactive medium. A dramatic increase in the power conversion efficiency (~20%) was witnessed for the BHJ PSCs treated with DHP compared to the pristine devices. A plausible explanation describing the alignment of pyridine moieties of DHP with the indene side groups of IC60BA is presented with a view to improving the performance of the BHJ PSCs via improved crystalline order and hydrophobicity changes.
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Affiliation(s)
- Binrui Xu
- School of Electronics Engineering, College of IT Engineering, Kyungpook National University, 80 Daehakro, Bukgu, Daegu 41566, Korea.
| | - Gopalan Sai-Anand
- Global Innovative Center for Advanced Nanomaterials, Faculty of Engineering and Built Environment, University of Newcastle, Callaghan, NSW 2298, Australia.
- Future Industries Institute, Division of Information Technology, Engineering and Environment, University of South Australia, Mawson Lakes, SA 5095, Australia.
| | - Anantha-Iyengar Gopalan
- Research Institute of Advanced Energy Technology, Kyungpook National University, Daegu 41566, Korea.
| | - Qiquan Qiao
- Center for Advanced Photovoltaics, Department of Electrical Engineering and Computer Science, South Dakota State University, Brookings, SD 570007, USA.
| | - Shin-Won Kang
- School of Electronics Engineering, College of IT Engineering, Kyungpook National University, 80 Daehakro, Bukgu, Daegu 41566, Korea.
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