1
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Xiang TF, Liu Z, Zheng T, Yang L, Tamiaki H, Sasaki SI, Li A, Wang XF. Coherent Charge Transfer Reveals a Different Theoretical Limit of Power Conversion Efficiency in Organic Solar Cells. J Phys Chem Lett 2024:9335-9341. [PMID: 39236264 DOI: 10.1021/acs.jpclett.4c01631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/07/2024]
Abstract
The hopping charge transfer (CT) theory is used to explain the dynamics of traditional donor-acceptor (D-A) devices in organic solar cells (OSCs). But it is not applicable to the unconventional OSCs inspired by photosynthesis, referred to as Z-devices. In this study, we establish a universal heterojunction CT model in OSCs, based on the reported coherent CT in photosynthesis. Compared to the trade-off between energy loss and charge generation efficiency in the D-A device, we analyze its change in the Z-device. We introduce the "avalanche-like" CT of the Z-device induced by many-body Coulomb interaction and relevant experimental support. Combining with the Shockley-Queisser theory, we evaluate the theory limit power conversion efficiency of a D-A device and a Z-device. The Z-device has the potential to surpass the Shockley-Queisser limit of 33%.
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Affiliation(s)
- Tian-Fu Xiang
- Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University, Changchun 130012, P. R. China
| | - Ziyan Liu
- Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University, Changchun 130012, P. R. China
| | - Tianfang Zheng
- Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University, Changchun 130012, P. R. China
| | - Lin Yang
- Key Laboratory for UV-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, 5268 Renmin Street, Changchun 130024, China
| | - Hitoshi Tamiaki
- Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Shin-Ichi Sasaki
- Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
- Department of Medical Bioscience, Faculty of Bioscience, Nagahama institute of Bio-Science and Technology, Nagahama, Shiga 5260829, Japan
| | - Aijun Li
- Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University, Changchun 130012, P. R. China
| | - Xiao-Feng Wang
- Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University, Changchun 130012, P. R. China
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2
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Rijal K, Fuller N, Rudayni F, Zhang N, Zuo X, Berrie CL, Yip HL, Chan WL. Endothermic Charge Separation Occurs Spontaneously in Non-Fullerene Acceptor/Polymer Bulk Heterojunction. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2400578. [PMID: 38762779 DOI: 10.1002/adma.202400578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 04/22/2024] [Indexed: 05/20/2024]
Abstract
Organic photovoltaics (OPVs) based on non-fullerene acceptors (NFAs) have achieved a power conversion efficiency close to 20%. These NFA OPVs can generate free carriers efficiently despite a very small energy level offset at the donor/acceptor interface. Why these NFAs can enable efficient charge separation (CS) with low energy losses remains an open question. Here, the CS process in the PM6:Y6 bulk heterojunction is probed by time-resolved two-photon photoemission spectroscopy. It is found that the CS, the conversion from bound charge transfer (CT) excitons to free carriers, is an endothermic process with an enthalpy barrier of 0.15 eV. The CS can occur spontaneously despite being an endothermic process, which implies that it is driven by entropy. It is further argued that the morphology of the PM6:Y6 film and the anisotropic electron delocalization restrict the electron and hole wavefunctions within the CT exciton such that they can primarily contact each other through point-like junctions. This configuration can maximize the entropic driving force.
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Affiliation(s)
- Kushal Rijal
- Department of Physics and Astronomy, University of Kansas, Lawrence, KS, 66045, USA
| | - Neno Fuller
- Department of Physics and Astronomy, University of Kansas, Lawrence, KS, 66045, USA
| | - Fatimah Rudayni
- Department of Physics and Astronomy, University of Kansas, Lawrence, KS, 66045, USA
- Department of Physics, Jazan University, Jazan, 45142, Saudi Arabia
| | - Nan Zhang
- Department of Materials Science and Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, 999077, Hong Kong
| | - Xiaobing Zuo
- X-ray Science Division, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Cindy L Berrie
- Department of Chemistry, University of Kansas, Lawrence, KS, 66045, USA
| | - Hin-Lap Yip
- Department of Materials Science and Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, 999077, Hong Kong
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, 999077, Hong Kong
- Hong Kong Institute for Clean Energy, City University of Hong Kong, Tat Chee Avenue, Kowloon, 999077, Hong Kong
- Center of Super-Diamond and Advanced Films, City University of Hong Kong, Tat Chee Avenue, Kowloon, 999077, Hong Kong
| | - Wai-Lun Chan
- Department of Physics and Astronomy, University of Kansas, Lawrence, KS, 66045, USA
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3
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Li J, Ji Q, Wang R, Zhang ZG, Wang X, Xiao M, Lu YQ, Zhang C. Charge Generation Dynamics in Organic Photovoltaic Blends under One-Sun-Equivalent Illumination Detected by Highly Sensitive Terahertz Spectroscopy. J Am Chem Soc 2024; 146:20312-20322. [PMID: 38980945 DOI: 10.1021/jacs.4c05786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/11/2024]
Abstract
Organic photovoltaic (OPV) devices attain high performance with nonfullerene acceptors by utilizing the synergistic dual channels of charge generation that originate from excitations in both the donor and acceptor materials. However, the specific intermediate states that facilitate both channels are subject to debate. To address this issue, we employ time-resolved terahertz spectroscopy with improved sensitivity (ΔE/E < 10-6), enabling direct probing of charge generation dynamics in a prototypical PM6:Y6 bulk heterojunction system under one-sun-equivalent excitation density. Charge generation arising from donor excitations is characterized with a rise time of ∼9 ps, while that from acceptor excitations shows a rise time of ∼18 ps. Temperature-dependent measurements further reveal notably distinct activation energies for these two charge generation pathways. Additionally, the two channels of charge generation can be substantially manipulated by altering the ratio of bulk to interfaces. These findings strongly suggest the presence of two distinct intermediate states: interfacial and intramoiety excitations. These states are crucial in mediating the transfer of electrons and holes, driving charge generation within OPV devices.
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Affiliation(s)
- Jiacong Li
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Qing Ji
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Rui Wang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, China
- College of Physics, Nanjing University of Aeronautics and Astronautics, and Key Laboratory of Aerospace Information Materials and Physics (NUAA), MIIT, Nanjing 211106, China
- Institute of Materials Engineering, Nanjing University, Nantong, Jiangsu 226019, China
| | - Zhi-Guo Zhang
- State Key Laboratory of Organic/Inorganic Composites, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Xiaoyong Wang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Min Xiao
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, China
- Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701, United States
| | - Yan-Qing Lu
- National Laboratory of Solid State Microstructures, Key Laboratory of Intelligent Optical Sensing and Manipulation, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210023, China
| | - Chunfeng Zhang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, China
- Institute of Materials Engineering, Nanjing University, Nantong, Jiangsu 226019, China
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4
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Bi P, Zhang T, Guo Y, Wang J, Chua XW, Chen Z, Goh WP, Jiang C, Chia EEM, Hou J, Yang L. Donor-acceptor bulk-heterojunction sensitizer for efficient solid-state infrared-to-visible photon up-conversion. Nat Commun 2024; 15:5719. [PMID: 38977685 PMCID: PMC11231359 DOI: 10.1038/s41467-024-50177-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Accepted: 07/03/2024] [Indexed: 07/10/2024] Open
Abstract
Solid-state infrared-to-visible photon up-conversion is important for spectral-tailoring applications. However, existing up-conversion systems not only suffer from low efficiencies and a need for high excitation intensity, but also exhibit a limited selection of materials and complex fabrication processes. Herein, we propose a sensitizer with a bulk-heterojunction structure, comprising both an energy donor and an energy acceptor, for triplet-triplet annihilation up-conversion devices. The up-conversion occurs through charge separation at the donor-acceptor interface, followed by the formation of charge transfer state between the energy donor and annihilator following the spin statistics. The bulk-heterojunction sensitizer ensures efficient charge generation and low charge recombination. Hence, we achieve a highly efficient solid-state up-conversion device with 2.20% efficiency and low excitation intensity (10 mW cm-2) through a one-step solution method. We also demonstrate bright up-conversion devices on highly-flexible large-area substrates. This study introduces a simple and scalable platform strategy for fabricating efficient up-conversion devices.
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Affiliation(s)
- Pengqing Bi
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore, 138634, Republic of Singapore
| | - Tao Zhang
- State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Yuanyuan Guo
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University (NTU), Singapore, 637371, Republic of Singapore
| | - Jianqiu Wang
- State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Xian Wei Chua
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore, 138634, Republic of Singapore
| | - Zhihao Chen
- State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Wei Peng Goh
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore, 138634, Republic of Singapore
| | - Changyun Jiang
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore, 138634, Republic of Singapore
| | - Elbert E M Chia
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University (NTU), Singapore, 637371, Republic of Singapore
| | - Jianhui Hou
- State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Le Yang
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore, 138634, Republic of Singapore.
- Department of Materials Science & Engineering, National University of Singapore (NUS), 9 Engineering Drive 1, Singapore, 117575, Republic of Singapore.
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5
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Rana A, Park SY, Labanti C, Fang F, Yun S, Dong Y, Yang EJ, Nodari D, Gasparini N, Park JI, Shin J, Minami D, Park KB, Kim JS, Durrant JR. Octupole moment driven free charge generation in partially chlorinated subphthalocyanine for planar heterojunction organic photodetectors. Nat Commun 2024; 15:5058. [PMID: 38871682 DOI: 10.1038/s41467-024-49169-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 05/27/2024] [Indexed: 06/15/2024] Open
Abstract
In this study, high-performance organic photodetectors are presented which utilize a pristine chlorinated subphthalocyanine photoactive layer. Optical and optoelectronic analyses indicate that the device photocurrent is primarily generated through direct charge generation within the chlorinated subphthalocyanine layer, rather than exciton separation at layer interfaces. Molecular modelling suggests that this direct charge generation is facilitated by chlorinated subphthalocyanine high octupole moment (-80 DÅ2), which generates a 200 meV shift in molecular energetics. Increasing the thickness of chlorinated subphthalocyanine leads to faster response time, correlated with a decrease in trap density. Notably, photodetectors with a 50 nm thick chlorinated subphthalocyanine photoactive layer exhibit detectivities approaching 1013 Jones, with a dark current below 10-7 A cm-2 up to -5 V. Based on these findings, we conclude that high octupole moment molecular semiconductors are promising materials for high-performance organic photodetectors employing single-component photoactive layer.
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Affiliation(s)
- Aniket Rana
- Department of Chemistry and Centre for Processable Electronics, Imperial College London, London, W12 0BZ, UK
| | - Song Yi Park
- Department of Physics and Centre for Processable Electronics, Imperial College London, London, SW7 2AZ, UK
- Department of Physics, Pukyong National University, Busan, 48513, Republic of Korea
| | - Chiara Labanti
- Department of Physics and Centre for Processable Electronics, Imperial College London, London, SW7 2AZ, UK
| | - Feifei Fang
- Organic Materials Lab, Samsung Advanced Institute of Technology, Samsung Electronics Co. Ltd., Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 16678, Republic of Korea
| | - Sungyoung Yun
- Organic Materials Lab, Samsung Advanced Institute of Technology, Samsung Electronics Co. Ltd., Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 16678, Republic of Korea
| | - Yifan Dong
- Department of Chemistry and Centre for Processable Electronics, Imperial College London, London, W12 0BZ, UK
- National Renewable Energy Laboratory, 15013 Denver W Pkwy, Golden, CO, 80401, USA
| | - Emily J Yang
- Department of Physics and Centre for Processable Electronics, Imperial College London, London, SW7 2AZ, UK
| | - Davide Nodari
- Department of Chemistry and Centre for Processable Electronics, Imperial College London, London, W12 0BZ, UK
| | - Nicola Gasparini
- Department of Chemistry and Centre for Processable Electronics, Imperial College London, London, W12 0BZ, UK
| | - Jeong-Il Park
- Organic Materials Lab, Samsung Advanced Institute of Technology, Samsung Electronics Co. Ltd., Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 16678, Republic of Korea
| | - Jisoo Shin
- Organic Materials Lab, Samsung Advanced Institute of Technology, Samsung Electronics Co. Ltd., Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 16678, Republic of Korea
| | - Daiki Minami
- Innovation Center, Samsung Electronics Co. Ltd., 1 Samsungjeonja-ro, Hwaseong-si, Gyeonggi-do, 18448, Republic of Korea
| | - Kyung-Bae Park
- Organic Materials Lab, Samsung Advanced Institute of Technology, Samsung Electronics Co. Ltd., Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 16678, Republic of Korea.
| | - Ji-Seon Kim
- Department of Physics and Centre for Processable Electronics, Imperial College London, London, SW7 2AZ, UK.
| | - James R Durrant
- Department of Chemistry and Centre for Processable Electronics, Imperial College London, London, W12 0BZ, UK.
- SPECIFIC, Faculty of Science and Engineering, Swansea University, Swansea, SA1 8EN, UK.
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6
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Mazumder A, Vinod K, Maret PD, Das PP, Hariharan M. Symmetry-Breaking Charge Separation Mediated Triplet Population in a Perylenediimide Trimer at the Single-Molecule Level. J Phys Chem Lett 2024; 15:5896-5904. [PMID: 38805687 DOI: 10.1021/acs.jpclett.4c01201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
Herein, we demonstrate triplet excited-state population in a conformationally rigid perylenediimide trimer (PDI-T) via intramolecular symmetry-breaking charge separation (SB-CS) at the single-molecule level. The single-molecule fluorescence intensity trajectories of PDI-T in nonpolar polystyrene matrix (ε = 2.60) exhibit prolonged fluorescence with infrequent dark states, representing the triplet and/or the charge transfer states. In contrast, in a poly(vinyl alcohol) matrix (ε = 7.80), erratic blinking dynamics resulting in low photon counts were observed, corroborating the feasibility of charge separation in a polar environment. In agreement with the single-molecule measurements, transient absorption spectroscopy of PDI-T reveals ultrafast SB-CS (τCS < 5 ps) in polar tetrahydrofuran (ε = 7.58) and acetone (ε = 20.70), with the population of the triplet excited-state through charge recombination. The current investigation shows the utility of rigid and weakly coupled molecular constructs in controlling triplet generation and SB-CS for potential applications in optoelectronic devices.
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Affiliation(s)
- Aniruddha Mazumder
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Maruthamala P.O., Vithura, Thiruvananthapuram, Kerala 695551, India
| | - Kavya Vinod
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Maruthamala P.O., Vithura, Thiruvananthapuram, Kerala 695551, India
| | - Philip Daniel Maret
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Maruthamala P.O., Vithura, Thiruvananthapuram, Kerala 695551, India
| | - Pallavi Panthakkal Das
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Maruthamala P.O., Vithura, Thiruvananthapuram, Kerala 695551, India
| | - Mahesh Hariharan
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Maruthamala P.O., Vithura, Thiruvananthapuram, Kerala 695551, India
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7
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Liu Z, Song Z, Sun X. All-Atom Photoinduced Charge Transfer Dynamics in Condensed Phase via Multistate Nonlinear-Response Instantaneous Marcus Theory. J Chem Theory Comput 2024; 20:3993-4006. [PMID: 38657208 PMCID: PMC11099976 DOI: 10.1021/acs.jctc.4c00010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 03/30/2024] [Accepted: 04/08/2024] [Indexed: 04/26/2024]
Abstract
Photoinduced charge transfer (CT) in the condensed phase is an essential component in solar energy conversion, but it is challenging to simulate such a process on the all-atom level. The traditional Marcus theory has been utilized for obtaining CT rate constants between pairs of electronic states but cannot account for the nonequilibrium effects due to the initial nuclear preparation. The recently proposed instantaneous Marcus theory (IMT) and its nonlinear-response formulation allow for incorporating the nonequilibrium nuclear relaxation to electronic transition between two states after the photoexcitation from the equilibrium ground state and provide the time-dependent rate coefficient. In this work, we extend the nonlinear-response IMT method for treating photoinduced CT among general multiple electronic states and demonstrate it in the organic photovoltaic carotenoid-porphyrin-fullerene triad dissolved in explicit tetrahydrofuran solvent. All-atom molecular dynamics simulations were employed to obtain the time correlation functions of energy gaps, which were used to generate the IMT-required time-dependent averages and variances of the relevant energy gaps. Our calculations show that the multistate IMT could capture the significant nonequilibrium effects due to the initial nuclear state preparation, and this is corroborated by the substantial differences between the population dynamics predicted by the multistate IMT and the Marcus theory, where the Marcus theory underestimates the population transfer. The population dynamics by multistate IMT is also shown to have a better agreement with the all-atom nonadiabatic mapping dynamics than the Marcus theory does. Because the multistate nonlinear-response IMT is straightforward and cost-effective in implementation and accounts for the nonequilibrium nuclear effects, we believe this method offers a practical strategy for studying charge transfer dynamics in complex condensed-phase systems.
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Affiliation(s)
- Zengkui Liu
- Division
of Arts and Sciences, NYU Shanghai, 567 West Yangsi Road, Shanghai 200124, China
- NYU-ECNU
Center for Computational Chemistry at NYU Shanghai, 3663 Zhongshan Road North, Shanghai 200062, China
- Department
of Chemistry, New York University, New York, New York 10003, United States
| | - Zailing Song
- Division
of Arts and Sciences, NYU Shanghai, 567 West Yangsi Road, Shanghai 200124, China
| | - Xiang Sun
- Division
of Arts and Sciences, NYU Shanghai, 567 West Yangsi Road, Shanghai 200124, China
- NYU-ECNU
Center for Computational Chemistry at NYU Shanghai, 3663 Zhongshan Road North, Shanghai 200062, China
- Department
of Chemistry, New York University, New York, New York 10003, United States
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8
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Wang Z, Guo Y, Liu X, Shu W, Han G, Ding K, Mukherjee S, Zhang N, Yip HL, Yi Y, Ade H, Chow PCY. The role of interfacial donor-acceptor percolation in efficient and stable all-polymer solar cells. Nat Commun 2024; 15:1212. [PMID: 38331998 PMCID: PMC10853271 DOI: 10.1038/s41467-024-45455-0] [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: 07/26/2023] [Accepted: 01/23/2024] [Indexed: 02/10/2024] Open
Abstract
Polymerization of Y6-type acceptor molecules leads to bulk-heterojunction organic solar cells with both high power-conversion efficiency and device stability, but the underlying mechanism remains unclear. Here we show that the exciton recombination dynamics of polymerized Y6-type acceptors (Y6-PAs) strongly depends on the degree of aggregation. While the fast exciton recombination rate in aggregated Y6-PA competes with electron-hole separation at the donor-acceptor (D-A) interface, the much-suppressed exciton recombination rate in dispersed Y6-PA is sufficient to allow efficient free charge generation. Indeed, our experimental results and theoretical simulations reveal that Y6-PAs have larger miscibility with the donor polymer than Y6-type small molecular acceptors, leading to D-A percolation that effectively prevents the formation of Y6-PA aggregates at the interface. Besides enabling high charge generation efficiency, the interfacial D-A percolation also improves the thermodynamic stability of the blend morphology, as evident by the reduced device "burn-in" loss upon solar illumination.
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Affiliation(s)
- Zhen Wang
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Yu Guo
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Xianzhao Liu
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Wenchao Shu
- CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Haidian, Beijing, 100190, China
| | - Guangchao Han
- CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Haidian, Beijing, 100190, China
| | - Kan Ding
- Department of Physics and Organic and Carbon Electronics Laboratories (ORaCEL), North Carolina State University, Raleigh, NC, 27695, USA
| | - Subhrangsu Mukherjee
- Department of Physics and Organic and Carbon Electronics Laboratories (ORaCEL), North Carolina State University, Raleigh, NC, 27695, USA
| | - Nan Zhang
- Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Hin-Lap Yip
- Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR, China
- School of Energy and Environment, City University of Hong Kong, Kowloon, Hong Kong SAR, China
- Hong Kong Institute for Clean Energy, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Yuanping Yi
- CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Haidian, Beijing, 100190, China
| | - Harald Ade
- Department of Physics and Organic and Carbon Electronics Laboratories (ORaCEL), North Carolina State University, Raleigh, NC, 27695, USA
| | - Philip C Y Chow
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China.
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9
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Bothra U, Westbrook RJE, Liu Y, Wang J, Ziffer ME, Ginger DS. Probing Charge Transfer Character in Modern Donor/Acceptor Materials via Electroabsorption Spectroscopy. J Phys Chem Lett 2024; 15:1288-1293. [PMID: 38278521 DOI: 10.1021/acs.jpclett.3c03262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2024]
Abstract
We use electroabsorption (EA) spectroscopy to probe the charge transfer (CT) character in neat films and blends of donors and acceptors of interest for organic electronic applications. In particular, we compare the CT character in two polymer donor and non-fullerene acceptor blends, including 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) and 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 (Y6). Like classic polymer/fullerene blends, the blend based on IT-4F exhibits primarily first derivative-like EA features, suggesting localized exciton formation upon photoexcitation. However, the Y6-based blend has an EA spectrum that is dominated by second derivative-like features, consistent with CT character. We show that this signal originates primarily from Y6. We find that Y6 exhibits the highest dipole moment change (7.5 ± 2.5 D) of the molecules that comprise this study, consistent with a high degree of the CT character, and a relatively large polarization volume of 361 ± 70 Å3, consistent with strong electron delocalization. These results point to the origins of exceptional performance of organic photovoltaics (OPVs) based on Y6.
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Affiliation(s)
- Urvashi Bothra
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Robert J E Westbrook
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Yun Liu
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Jian Wang
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Mark E Ziffer
- Department of Physics, Columbia University, New York, New York 10027, United States
| | - David S Ginger
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
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10
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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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11
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Zhang KN, Du XY, Yan L, Pu YJ, Tajima K, Wang X, Hao XT. Organic Photovoltaic Stability: Understanding the Role of Engineering Exciton and Charge Carrier Dynamics from Recent Progress. SMALL METHODS 2024; 8:e2300397. [PMID: 37204077 DOI: 10.1002/smtd.202300397] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 04/25/2023] [Indexed: 05/20/2023]
Abstract
Benefiting from the synergistic development of material design, device engineering, and the mechanistic understanding of device physics, the certified power conversion efficiencies (PCEs) of single-junction non-fullerene organic solar cells (OSCs) have already reached a very high value of exceeding 19%. However, in addition to PCEs, the poor stability is now a challenging obstacle for commercial applications of organic photovoltaics (OPVs). Herein, recent progress made in exploring operational mechanisms, anomalous photoelectric behaviors, and improving long-term stability in non-fullerene OSCs are highlighted from a novel and previously largely undiscussed perspective of engineering exciton and charge carrier pathways. Considering the intrinsic connection among multiple temporal-scale photocarrier dynamics, multi-length scale morphologies, and photovoltaic performance in OPVs, this review delineates and establishes a comprehensive and in-depth property-function relationship for evaluating the actual device stability. Moreover, this review has also provided some valuable photophysical insights into employing the advanced characterization techniques such as transient absorption spectroscopy and time-resolved fluorescence imagings. Finally, some of the remaining major challenges related to this topic are proposed toward the further advances of enhancing long-term operational stability in non-fullerene OSCs.
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Affiliation(s)
- Kang-Ning Zhang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong, 250100, P. R. China
| | - Xiao-Yan Du
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong, 250100, P. R. China
| | - Lei Yan
- Academy for Advanced Interdisciplinary Studies and Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, P. R. China
| | - Yong-Jin Pu
- RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Keisuke Tajima
- RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Xingzhu Wang
- Academy for Advanced Interdisciplinary Studies and Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, P. R. China
- School of Electrical Engineering, University of South China, Hengyang, 421001, P. R. China
| | - Xiao-Tao Hao
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong, 250100, P. R. China
- ARC Centre of Excellence in Exciton Science, School of Chemistry, The University of Melbourne, Parkville, Victoria, 3010, Australia
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12
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Rasool S, Yeop J, An NG, Kim JW, Kim JY. Role of Charge-Carrier Dynamics Toward the Fabrication of Efficient Air-Processed Organic Solar Cells. SMALL METHODS 2024; 8:e2300578. [PMID: 37649231 DOI: 10.1002/smtd.202300578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 08/10/2023] [Indexed: 09/01/2023]
Abstract
Over the past couple of decades, immense research has been carried out to understand the photo-physics of an organic solar cell (OSC) that is important to enhance its efficiency and stability. Since OSCs undergoes complex photophysical phenomenon, studying these factors has led to designing new materials and implementing new strategies to improve efficiency in OSCs. In this regard, the invention of the non-fullerene acceptorshas greatly revolutionized the understanding of the fundamental processes occurring in OSCs. However, such vital fundamental research from device physics perspectives is carried out on glovebox (GB) processed OSCs and there is a scarcity of research on air-processed (AP) OSCs. This review will focus on charge carrier dynamics such as exciton diffusion, exciton dissociation, charge-transfer states, significance of highest occupied molecular orbital-offsets, and hole-transfer efficiencies of GB-OSCs and compare them with the available data from the AP-OSCs. Finally, key requirements for the fabrication of efficient AP-OSCs will be presented from a charge-carrier dynamics perspective. The key aspects from the charge-carrier dynamics view to fabricate efficient OSCs either from GB or air are provided.
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Affiliation(s)
- Shafket Rasool
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Ulsan, 44919, South Korea
| | - Jiwoo Yeop
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Ulsan, 44919, South Korea
| | - Na Gyeong An
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Ulsan, 44919, South Korea
- Department of Chemical and Biological Engineering, Monash University, Victoria, 3800, Australia
- Commonwealth Scientific and Industrial Research Organization (CSIRO) Manufacturing, Clayton, Victoria, 3168, Australia
| | - Jae Won Kim
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Ulsan, 44919, South Korea
| | - Jin Young Kim
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Ulsan, 44919, South Korea
- Graduate School of Carbon Neutrality, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Ulsan, 44919, South Korea
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13
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Liu Q, Vandewal K. Understanding and Suppressing Non-Radiative Recombination Losses in Non-Fullerene Organic Solar Cells. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2302452. [PMID: 37201949 DOI: 10.1002/adma.202302452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 04/26/2023] [Indexed: 05/20/2023]
Abstract
Organic solar cells benefit from non-fullerene acceptors (NFA) due to their high absorption coefficients, tunable frontier energy levels, and optical gaps, as well as their relatively high luminescence quantum efficiencies as compared to fullerenes. Those merits result in high yields of charge generation at a low or negligible energetic offset at the donor/NFA heterojunction, with efficiencies over 19% achieved for single-junction devices. Pushing this value significantly over 20% requires an increase in open-circuit voltage, which is currently still well below the thermodynamic limit. This can only be achieved by reducing non-radiative recombination, and hereby increasing the electroluminescence quantum efficiency of the photo-active layer. Here, current understanding of the origin of non-radiative decay, as well as an accurate quantification of the associated voltage losses are summarized. Promising strategies for suppressing these losses are highlighted, with focus on new material design, optimization of donor-acceptor combination, and blend morphology. This review aims at guiding researchers in their quest to find future solar harvesting donor-acceptor blends, which combine a high yield of exciton dissociation with a high yield of radiative free carrier recombination and low voltage losses, hereby closing the efficiency gap with inorganic and perovskite photovoltaics.
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Affiliation(s)
- Quan Liu
- Hasselt University, IMOMEC, Wetenschapspark 1, Diepenbeek, 3590, Belgium
- Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China
| | - Koen Vandewal
- Hasselt University, IMOMEC, Wetenschapspark 1, Diepenbeek, 3590, Belgium
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14
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Zhu C, Chung S, Zhao J, Sun Y, Zhao B, Zhao Z, Kim S, Cho K, Kan Z. Vertical Phase Regulation with 1,3,5-Tribromobenzene Leads to 18.5% Efficiency Binary Organic Solar Cells. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2303150. [PMID: 37424039 PMCID: PMC10502666 DOI: 10.1002/advs.202303150] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 06/19/2023] [Indexed: 07/11/2023]
Abstract
The sequential deposition method assists the vertical phase distribution in the photoactive layer of organic solar cells, enhancing power conversion efficiencies. With this film coating approach, the morphology of both layers can be fine-tuned with high boiling solvent additives, as frequently applied in one-step casting films. However, introducing liquid additives can compromise the morphological stability of the devices due to the solvent residuals. Herein, 1,3,5-tribromobenzene (TBB) with high volatility and low cost, is used as a solid additive in the acceptor solution and combined thermal annealing to regulate the vertical phase in organic solar cells composed of D18-Cl/L8-BO. Compared to the control cells, the devices treated with TBB and those that underwent additional thermal processing exhibit increased exciton generation rate, charge carrier mobility, charge carrier lifetime, and reduced bimolecular charge recombination. As a result, the TBB-treated organic solar cells achieve a champion power conversion efficiency of 18.5% (18.1% averaged), one of the highest efficiencies in binary organic solar cells with open circuit voltage exceeding 900 mV. This study ascribes the advanced device performance to the gradient-distributed donor-acceptor concentrations in the vertical direction. The findings provide guidelines for optimizing the morphology of the sequentially deposited top layer to achieve high-performance organic solar cells.
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Affiliation(s)
- Chaofeng Zhu
- Center on Nanoenergy ResearchGuangxi Colleges and Universities Key Laboratory of Blue Energy and Systems IntegrationCarbon Peak and Neutrality Science and Technology Development InstituteSchool of Physical Science & TechnologyGuangxi UniversityNanning530004China
| | - Sein Chung
- Department of Chemical EngineeringPohang University of Science and Technology77 Cheongam‐ro, Nam‐guPohang‐si37673South Korea
| | - Jingjing Zhao
- Center on Nanoenergy ResearchGuangxi Colleges and Universities Key Laboratory of Blue Energy and Systems IntegrationCarbon Peak and Neutrality Science and Technology Development InstituteSchool of Physical Science & TechnologyGuangxi UniversityNanning530004China
| | - Yuqing Sun
- Center on Nanoenergy ResearchGuangxi Colleges and Universities Key Laboratory of Blue Energy and Systems IntegrationCarbon Peak and Neutrality Science and Technology Development InstituteSchool of Physical Science & TechnologyGuangxi UniversityNanning530004China
| | - Bin Zhao
- Center on Nanoenergy ResearchGuangxi Colleges and Universities Key Laboratory of Blue Energy and Systems IntegrationCarbon Peak and Neutrality Science and Technology Development InstituteSchool of Physical Science & TechnologyGuangxi UniversityNanning530004China
| | - Zhenmin Zhao
- Center on Nanoenergy ResearchGuangxi Colleges and Universities Key Laboratory of Blue Energy and Systems IntegrationCarbon Peak and Neutrality Science and Technology Development InstituteSchool of Physical Science & TechnologyGuangxi UniversityNanning530004China
| | - Seunghyun Kim
- Department of Chemical EngineeringPohang University of Science and Technology77 Cheongam‐ro, Nam‐guPohang‐si37673South Korea
| | - Kilwon Cho
- Department of Chemical EngineeringPohang University of Science and Technology77 Cheongam‐ro, Nam‐guPohang‐si37673South Korea
| | - Zhipeng Kan
- Center on Nanoenergy ResearchGuangxi Colleges and Universities Key Laboratory of Blue Energy and Systems IntegrationCarbon Peak and Neutrality Science and Technology Development InstituteSchool of Physical Science & TechnologyGuangxi UniversityNanning530004China
- State Key Laboratory of Featured Metal Materials and Life‐cycle Safety for Composite StructuresNanning530004China
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15
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Li Q, Wang R, Yu T, Wang X, Zhang ZG, Zhang Y, Xiao M, Zhang C. Long-Range Charge Separation Enabled by Intramoiety Delocalized Excitations in Copolymer Donors in Organic Photovoltaic Blends. J Phys Chem Lett 2023; 14:7498-7506. [PMID: 37581453 DOI: 10.1021/acs.jpclett.3c01861] [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
For over two decades, most high-performance organic photovoltaics (OPVs) have been made with donor:acceptor bulk heterojunctions with domain sizes limited by exciton diffusion, where charge separation mostly takes place through the dissociation of the interfacial charge-transfer (xCT) excitons. Recently, nonfullerene acceptor (NFA)-based OPVs have shown excellent compatibility to device structures with large domains in active layers. However, it remains elusive how the excitations that are distant from the interfaces are converted into free charges. Here, we report the identification of a new charge separation channel in model copolymer/NFA blends mediated by intra-moiety delocalized excitations in both planar heterojunctions and donor-enriched bulk heterojunctions. The delocalized excitations induced by interchromophore electronic interactions in copolymer donors mediate the long-range charge separation and dissociate into free charges without forming the bound xCT states first, releasing the constraints associated with the short exciton diffusion length in organic materials. The long-range charge separation mechanism uncovered in this work, in cooperation with the short-range xCT-mediated pathway, holds the potential to further optimize OPVs with diverse device structures.
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Affiliation(s)
- Qian Li
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Rui Wang
- College of Physics, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, China
- Key Laboratory of Aerospace Information Materials and Physics (NUAA), MIIT, Nanjing 211106, China
| | - Tao Yu
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Xiaoyong Wang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Zhi-Guo Zhang
- State Key Laboratory of Organic/Inorganic Composites, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Yuan Zhang
- School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
| | - Min Xiao
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, China
- Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701, United States
| | - Chunfeng Zhang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, China
- Institute of Materials Engineering, Nanjing University, Nantong, Jiangsu 226001, China
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16
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Ji Y, Mu X, Yin H, Cui B, Hao X, Gao K. Revealing the Role of Donor/Acceptor Interfaces in Nonfullerene-Acceptor Based Organic Solar Cells: Charge Separation versus Recombination. J Phys Chem Lett 2023; 14:3811-3817. [PMID: 37057899 DOI: 10.1021/acs.jpclett.3c00282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Organic solar cells (OSCs) based on nonfullerene-acceptors (NFAs) have achieved rapid development, while the role of donor/acceptor (D/A) interfaces in NFA based heterosystems has not been fully addressed. Here, we clarify that the photoinduced spontaneous charge separation efficiency in typical NFA heterosystems can reach up to 67%, and the charge separation efficiency contributed by the D/A interface is only 25%. The more important role of D/A interfaces is reducing the charge recombination rate, especially optimizing the competition between radiative and nonradiative charge recombination, thus reducing the nonradiative voltage loss. Systematical simulations demonstrate that there exists an optimal interfacial distance for a fixed energy offset, at which the D/A interface can reduce the nonradiative voltage loss by a maximum value of 0.12 V. Hence, we propose that optimizing the interfacial distance combined with the actual interfacial energy offset of a given heterosystem is important to develop its best photovoltaic performance.
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Affiliation(s)
- Yiwen Ji
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Xinyu Mu
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Hang Yin
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Bin Cui
- 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
| | - Kun Gao
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
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17
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Li Q, Wang R, Zhang C. The Dynamics of Delocalized Excitations in Organic Solar Cells with Nonfullerene Acceptors. J Phys Chem Lett 2023; 14:3031-3038. [PMID: 36946622 DOI: 10.1021/acs.jpclett.2c03911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Recently, the performance of organic solar cells has been markedly improved benefiting from the development of nonfullerene acceptors (NFAs) with acceptor-donor-acceptor structures. Arising from the intermolecular electronic interactions between the electron donating and accepting units, intramoiety and interfacial delocalized excitations make a substantial contribution to the photocurrent generation. In this Perspective, we discuss recent studies on the excited-state dynamics responsible for the working mechanism in NFA-based organic solar cells and emphasize the dynamics of delocalized excitations in charge generation and recombination processes. The intramoiety delocalized excitations in NFAs enable charge separation without forming interfacial charge-transfer excitons first, allowing efficient photocharge generation in planar heterojunctions with reduced interfacial energy loss. We suggest a few research directions in elucidating the performance-limited processes toward the further optimization of NFA-based devices.
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Affiliation(s)
- Qian Li
- National Laboratory of Solid-State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Rui Wang
- National Laboratory of Solid-State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Chunfeng Zhang
- National Laboratory of Solid-State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, China
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18
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Baikie TK, Wey LT, Lawrence JM, Medipally H, Reisner E, Nowaczyk MM, Friend RH, Howe CJ, Schnedermann C, Rao A, Zhang JZ. Photosynthesis re-wired on the pico-second timescale. Nature 2023; 615:836-840. [PMID: 36949188 DOI: 10.1038/s41586-023-05763-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 01/26/2023] [Indexed: 03/24/2023]
Abstract
Photosystems II and I (PSII, PSI) are the reaction centre-containing complexes driving the light reactions of photosynthesis; PSII performs light-driven water oxidation and PSI further photo-energizes harvested electrons. The impressive efficiencies of the photosystems have motivated extensive biological, artificial and biohybrid approaches to 're-wire' photosynthesis for higher biomass-conversion efficiencies and new reaction pathways, such as H2 evolution or CO2 fixation1,2. Previous approaches focused on charge extraction at terminal electron acceptors of the photosystems3. Electron extraction at earlier steps, perhaps immediately from photoexcited reaction centres, would enable greater thermodynamic gains; however, this was believed impossible with reaction centres buried at least 4 nm within the photosystems4,5. Here, we demonstrate, using in vivo ultrafast transient absorption (TA) spectroscopy, extraction of electrons directly from photoexcited PSI and PSII at early points (several picoseconds post-photo-excitation) with live cyanobacterial cells or isolated photosystems, and exogenous electron mediators such as 2,6-dichloro-1,4-benzoquinone (DCBQ) and methyl viologen. We postulate that these mediators oxidize peripheral chlorophyll pigments participating in highly delocalized charge-transfer states after initial photo-excitation. Our results challenge previous models that the photoexcited reaction centres are insulated within the photosystem protein scaffold, opening new avenues to study and re-wire photosynthesis for biotechnologies and semi-artificial photosynthesis.
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Affiliation(s)
- Tomi K Baikie
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
| | - Laura T Wey
- Department of Biochemistry, University of Cambridge, Cambridge, UK
- Department of Life Technologies, University of Turku, Turku, Finland
| | - Joshua M Lawrence
- Department of Biochemistry, University of Cambridge, Cambridge, UK
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
| | | | - Erwin Reisner
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Marc M Nowaczyk
- Plant Biochemistry, Ruhr University Bochum, Bochum, Germany
- Department of Biochemistry, University of Rostock, Rostock, Germany
| | | | | | | | - Akshay Rao
- Cavendish Laboratory, University of Cambridge, Cambridge, UK.
| | - Jenny Z Zhang
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK.
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19
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Lowrie W, Westbrook RJE, Guo J, Gonev HI, Marin-Beloqui J, Clarke TM. Organic photovoltaics: The current challenges. J Chem Phys 2023; 158:110901. [PMID: 36948814 DOI: 10.1063/5.0139457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023] Open
Abstract
Organic photovoltaics are remarkably close to reaching a landmark power conversion efficiency of 20%. Given the current urgent concerns regarding climate change, research into renewable energy solutions is crucially important. In this perspective article, we highlight several key aspects of organic photovoltaics, ranging from fundamental understanding to implementation, that need to be addressed to ensure the success of this promising technology. We cover the intriguing ability of some acceptors to undergo efficient charge photogeneration in the absence of an energetic driving force and the effects of the resulting state hybridization. We explore one of the primary loss mechanisms of organic photovoltaics-non-radiative voltage losses-and the influence of the energy gap law. Triplet states are becoming increasingly relevant owing to their presence in even the most efficient non-fullerene blends, and we assess their role as both a loss mechanism and a potential strategy to enhance efficiency. Finally, two ways in which the implementation of organic photovoltaics can be simplified are addressed. The standard bulk heterojunction architecture could be superseded by either single material photovoltaics or sequentially deposited heterojunctions, and the attributes of both are considered. While several important challenges still lie ahead for organic photovoltaics, their future is, indeed, bright.
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Affiliation(s)
- William Lowrie
- Department of Chemistry, University College London, Christopher Ingold Building, London WC1H 0AJ, United Kingdom
| | - Robert J E Westbrook
- Department of Chemistry, University of Washington, Seattle, Washington 98195, USA
| | - Junjun Guo
- Department of Chemistry, University College London, Christopher Ingold Building, London WC1H 0AJ, United Kingdom
| | - Hristo Ivov Gonev
- Department of Chemistry, University College London, Christopher Ingold Building, London WC1H 0AJ, United Kingdom
| | - Jose Marin-Beloqui
- Departamento de Química Física, Universidad de Malaga, Campus Teatinos s/n, 29071 Málaga, Spain
| | - Tracey M Clarke
- Department of Chemistry, University College London, Christopher Ingold Building, London WC1H 0AJ, United Kingdom
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20
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Wang T, Chen ZH, Qiao JW, Qin W, Liu JQ, Wang XZ, Pu YJ, Yin H, Hao XT. Correlating Charge Transfer Dynamics with Interfacial Trap States in High-Efficiency Organic Solar Cells. ACS APPLIED MATERIALS & INTERFACES 2023; 15:12109-12118. [PMID: 36813758 DOI: 10.1021/acsami.2c21470] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The charge transfer between the donor and acceptor determines the photogenerated carrier density in organic solar cells. However, a fundamental understanding regarding the charge transfer at donor/acceptor interfaces with high-density traps has not been fully addressed. Herein, a general correlation between trap densities and charge transfer dynamics is established by adopting a series of high-efficiency organic photovoltaic blends. It is found that the electron transfer rates are reduced with increased trap densities, while the hole transfer rates are independent of trap states. The local charges captured by traps can induce potential barrier formation around recombination centers, leading to the suppression of electron transfer. For the hole transfer process, the thermal energy provides a sufficient driving force, which ensures an efficient transfer rate. As a result, a 17.18% efficiency is obtained for PM6:BTP-eC9-based devices with the lowest interfacial trap densities. This work highlights the importance of interfacial traps in charge transfer processes and proposes an underlying insight into the charge transfer mechanism at nonideal interfaces in organic heterostructures.
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Affiliation(s)
- Tong Wang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, Shandong, China
| | - Zhi-Hao Chen
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, Shandong, China
| | - Jia-Wei Qiao
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, Shandong, China
| | - Wei Qin
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, Shandong, China
| | - Jian-Qiang Liu
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, Shandong, China
| | - Xing-Zhu Wang
- Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen 518055, Guangdong Province, China
| | - Yong-Jin Pu
- RIKEN Center for Emergent Matter Science (CEMS)2-1 Hirosawa, Wako 351-0198, Saitama, Japan
| | - Hang Yin
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, Shandong, China
| | - Xiao-Tao Hao
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, Shandong, China
- ARC Centre of Excellence in Exciton Science, School of Chemistry, The University of Melbourne, Parkville 3010, Victoria, Australia
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21
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Li S, Zhan L, Li Y, He C, Zuo L, Shi M, Chen H. Achieving and Understanding of Highly Efficient Ternary Organic Photovoltaics: From Morphology and Energy Loss to Working Mechanism. SMALL METHODS 2022; 6:e2200828. [PMID: 35931458 DOI: 10.1002/smtd.202200828] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 07/22/2022] [Indexed: 06/15/2023]
Abstract
Ternary strategy, adding an additional donor (D) or acceptor (A) into conventional binary D:A blend, has shown great potential in improving photovoltaic performances of organic photovoltaics (OPVs) for practical applications. Herein, this review is presented on how efficient ternary OPVs are realized from the aspects of morphology, energy loss, and working mechanism. As to morphology, the role of third component on the formation of preferred alloy-like-phase and vertical-phase, which are driven by the miscibility tuning, is discussed. For energy loss, the effect of the third component on the luminescence enhancement and energetic disordering suppression, which lead to favorable increase of voltage, is presented. Regarding working mechanism, dilution effect and relationships between two acceptors or donor/acceptor, which explain the observed device parameters variations, are analyzed. Finally, some future directions concerning ternary OPVs are pointed out. Therefore, this review can provide a comprehensive understanding of working principles and effective routes for high-efficiency ternary systems, advancing the commercialization of OPVs.
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Affiliation(s)
- Shuixing Li
- State Key Laboratory of Silicon Materials, MOE Key Laboratory of Macromolecular Synthesis and Functionalization, International Research Center for X Polymers, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, 310027, P. R. China
| | - Lingling Zhan
- State Key Laboratory of Silicon Materials, MOE Key Laboratory of Macromolecular Synthesis and Functionalization, International Research Center for X Polymers, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, 310027, P. R. China
- Key Laboratory of Organosilicon Chemistry and Materials Technology of Ministry of Education, College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou, 311121, P. R. China
| | - Yaokai Li
- State Key Laboratory of Silicon Materials, MOE Key Laboratory of Macromolecular Synthesis and Functionalization, International Research Center for X Polymers, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, 310027, P. R. China
| | - Chengliang He
- State Key Laboratory of Silicon Materials, MOE Key Laboratory of Macromolecular Synthesis and Functionalization, International Research Center for X Polymers, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, 310027, P. R. China
| | - Lijian Zuo
- State Key Laboratory of Silicon Materials, MOE Key Laboratory of Macromolecular Synthesis and Functionalization, International Research Center for X Polymers, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, 310027, P. R. China
- Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering, Hangzhou, 310027, P. R. China
| | - Minmin Shi
- State Key Laboratory of Silicon Materials, MOE Key Laboratory of Macromolecular Synthesis and Functionalization, International Research Center for X Polymers, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, 310027, P. R. China
- Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering, Hangzhou, 310027, P. R. China
| | - Hongzheng Chen
- State Key Laboratory of Silicon Materials, MOE Key Laboratory of Macromolecular Synthesis and Functionalization, International Research Center for X Polymers, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, 310027, P. R. China
- Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering, Hangzhou, 310027, P. R. China
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22
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Intralayer charge-transfer moiré excitons in van der Waals superlattices. Nature 2022; 609:52-57. [PMID: 36045239 DOI: 10.1038/s41586-022-04991-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 06/17/2022] [Indexed: 11/08/2022]
Abstract
Moiré patterns of transition metal dichalcogenide heterobilayers have proved to be an ideal platform on which to host unusual correlated electronic phases, emerging magnetism and correlated exciton physics. Whereas the existence of new moiré excitonic states is established1-4 through optical measurements, the microscopic nature of these states is still poorly understood, often relying on empirically fit models. Here, combining large-scale first-principles GW (where G and W denote the one-particle Green's function and the screened Coulomb interaction, respectively) plus Bethe-Salpeter calculations and micro-reflection spectroscopy, we identify the nature of the exciton resonances in WSe2/WS2 moiré superlattices, discovering a rich set of moiré excitons that cannot be captured by prevailing continuum models. Our calculations show moiré excitons with distinct characters, including modulated Wannier excitons and previously unidentified intralayer charge-transfer excitons. Signatures of these distinct excitonic characters are confirmed experimentally by the unique carrier-density and magnetic-field dependences of different moiré exciton resonances. Our study highlights the highly non-trivial exciton states that can emerge in transition metal dichalcogenide moiré superlattices, and suggests new ways of tuning many-body physics in moiré systems by engineering excited-states with specific spatial characters.
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23
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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: 149] [Impact Index Per Article: 74.5] [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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24
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Zhang L, Zhang Z, Deng D, Zhou H, Zhang J, Wei Z. "N-π-N" Type Oligomeric Acceptor Achieves an OPV Efficiency of 18.19% with Low Energy Loss and Excellent Stability. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2202513. [PMID: 35712769 PMCID: PMC9376851 DOI: 10.1002/advs.202202513] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 05/20/2022] [Indexed: 05/25/2023]
Abstract
A novel "N-π-N" type oligomeric acceptor of 2BTP-2F-T, constructed by two small non-fullerene acceptor (NFA) units linked with a thiophene π bridge is reported. The 2BTP-2F-T not only combines the advantages of small NFA and polymeric acceptors (PYF-T-o) with similar units but also exhibits superior characteristics of high absorption coefficient and high electron moblity(µe) ) with less dependence on molecular packing. Using PM6 as the donor, a remarkable efficiency of 18.19% is obtained with an open circuit (Voc ) of 0.911 V, short current circuit (Jsc ) of 25.50 mA cm-2 , and fill factor (FF) of 78.3%, which is much better than that of the corresponding monomer (16.54%) and PYF-T-o (15.8%) based devices. The much-improved efficiency results from two aspects: 1) an enhanced FF due to the largely improved µe and well-controlled morphology ; 2) a higher value of (Jsc × Voc ) due to its higher absorption coefficient and efficient charge generation at a similar low energy loss. Furthermore, the PM6/2BTP-2F-T device possesses the longest T80 lifetime to light-soaking and comparable high thermal stability with PM6/PYF-T-o. The results indicate that the "N-π-N" type oligomeric acceptor has a great application prospect due to its superior high efficiency and improved stability in organic solar cells.
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Affiliation(s)
- Lili Zhang
- CAS Key Laboratory of Nanosystem and Hierarchical FabricationNational Center for Nanoscience and TechnologyBeijing100190China
- Sino‐Danish Center for Education and ResearchSino‐Danish CollegeUniversity of Chinese Academy of SciencesBeijing100190China
| | - Ziqi Zhang
- CAS Key Laboratory of Nanosystem and Hierarchical FabricationNational Center for Nanoscience and TechnologyBeijing100190China
- School of Nanoscience and TechnologyUniversity of Chinese Academy of SciencesBeijing100049China
| | - Dan Deng
- CAS Key Laboratory of Nanosystem and Hierarchical FabricationNational Center for Nanoscience and TechnologyBeijing100190China
- School of Nanoscience and TechnologyUniversity of Chinese Academy of SciencesBeijing100049China
| | - Huiqiong Zhou
- CAS Key Laboratory of Nanosystem and Hierarchical FabricationNational Center for Nanoscience and TechnologyBeijing100190China
| | - Jianqi Zhang
- CAS Key Laboratory of Nanosystem and Hierarchical FabricationNational Center for Nanoscience and TechnologyBeijing100190China
- School of Nanoscience and TechnologyUniversity of Chinese Academy of SciencesBeijing100049China
| | - Zhixiang Wei
- CAS Key Laboratory of Nanosystem and Hierarchical FabricationNational Center for Nanoscience and TechnologyBeijing100190China
- School of Nanoscience and TechnologyUniversity of Chinese Academy of SciencesBeijing100049China
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25
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Lei Y, Zheng Z, Vasquez L, Zhao J, Ma J, Ma H. Enhanced Electron Transfer and Spin Flip through Spin-Orbital Couplings in Organic/Inorganic Heterojunctions: A Nonadiabatic Surface Hopping Simulation. J Phys Chem Lett 2022; 13:4840-4848. [PMID: 35616399 DOI: 10.1021/acs.jpclett.2c01177] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The circumstances of transferred electrons across organic/inorganic interfaces have attracted intensive interest because of the distinctive electronic structure properties of those two components. Leveraging ab initio nonadiabatic molecular dynamics methods in conjunction with spin dynamics induced by spin-orbital couplings (SOCs), this study reports two competitive channels during photoinduced dynamical processes in the prototypical ZnPc/monolayer MoS2 heterojunction. Interestingly, the electron-transfer and relaxation processes occur simultaneously because of the enhancement of electron-phonon couplings and expansion of dynamical pathways by SOCs, suggesting that the electron-transfer rate and relaxation processes can be tuned by SOCs, hence yielding the performance promotion of photovoltaic and photocatalytic devices. Additionally, approximately half of the transferred electrons flip their spin within 1.6 ps because of strong SOCs in MoS2, achieving great agreement with experimental measurements. This investigation provides instructive perspectives for designing novel devices and applications based on organic/inorganic heterojunctions, demonstrating the importance of spin dynamics simulations in exploring sophisticated photoinduced processes in materials.
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Affiliation(s)
- Yuli Lei
- Jiangsu Key Laboratory of Vehicle Emissions Control, Key Laboratory of Mesoscopic Chemistry of Ministry of Education, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Zhenfa Zheng
- Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Luis Vasquez
- Jiangsu Key Laboratory of Vehicle Emissions Control, Key Laboratory of Mesoscopic Chemistry of Ministry of Education, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Jin Zhao
- Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Jing Ma
- Jiangsu Key Laboratory of Vehicle Emissions Control, Key Laboratory of Mesoscopic Chemistry of Ministry of Education, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Haibo Ma
- Jiangsu Key Laboratory of Vehicle Emissions Control, Key Laboratory of Mesoscopic Chemistry of Ministry of Education, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
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26
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Riley DB, Meredith P, Armin A, Sandberg OJ. Role of Exciton Diffusion and Lifetime in Organic Solar Cells with a Low Energy Offset. J Phys Chem Lett 2022; 13:4402-4409. [PMID: 35549280 PMCID: PMC9150110 DOI: 10.1021/acs.jpclett.2c00791] [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: 03/17/2022] [Accepted: 05/03/2022] [Indexed: 06/15/2023]
Abstract
Despite general agreement that the generation of free charges in organic solar cells is driven by an energetic offset, power conversion efficiencies have been improved using low-offset blends. In this work, we explore the interconnected roles that exciton diffusion and lifetime play in the charge generation process under various energetic offsets. A detailed balance approach is used to develop an analytic framework for exciton dissociation and free-charge generation accounting for exciton diffusion to and dissociation at the donor-acceptor interface. For low-offset systems, we find the exciton lifetime to be a pivotal component in the charge generation process, as it influences both the exciton and CT state dissociation. These findings suggest that any novel low-offset material combination must have long diffusion lengths with long exciton lifetimes to achieve optimum charge generation yields.
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Affiliation(s)
- Drew B. Riley
- Sustainable Advanced Materials
Programme (Sêr SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, United
Kingdom
| | - Paul Meredith
- Sustainable Advanced Materials
Programme (Sêr SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, United
Kingdom
| | - Ardalan Armin
- Sustainable Advanced Materials
Programme (Sêr SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, United
Kingdom
| | - Oskar J. Sandberg
- Sustainable Advanced Materials
Programme (Sêr SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, United
Kingdom
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27
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Zeiske S, Sandberg OJ, Kurpiers J, Shoaee S, Meredith P, Armin A. Probing Charge Generation Efficiency in Thin-Film Solar Cells by Integral-Mode Transient Charge Extraction. ACS PHOTONICS 2022; 9:1188-1195. [PMID: 35571262 PMCID: PMC9097587 DOI: 10.1021/acsphotonics.1c01532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Indexed: 06/15/2023]
Abstract
The photogeneration of free charges in light-harvesting devices is a multistep process, which can be challenging to probe due to the complexity of contributing energetic states and the competitive character of different driving mechanisms. In this contribution, we advance a technique, integral-mode transient charge extraction (ITCE), to probe these processes in thin-film solar cells. ITCE combines capacitance measurements with the integral-mode time-of-flight method in the low intensity regime of sandwich-type thin-film devices and allows for the sensitive determination of photogenerated charge-carrier densities. We verify the theoretical framework of our method by drift-diffusion simulations and demonstrate the applicability of ITCE to organic and perovskite semiconductor-based thin-film solar cells. Furthermore, we examine the field dependence of charge generation efficiency and find our ITCE results to be in excellent agreement with those obtained via time-delayed collection field measurements conducted on the same devices.
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Affiliation(s)
- Stefan Zeiske
- Sustainable
Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, Wales, United Kingdom
| | - Oskar J. Sandberg
- Sustainable
Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, Wales, United Kingdom
| | - Jona Kurpiers
- Disordered Semiconductor Optoelectronics,
Institute
of Physics and Astronomy, University Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany
| | - Safa Shoaee
- Disordered Semiconductor Optoelectronics,
Institute
of Physics and Astronomy, University Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany
| | - Paul Meredith
- Sustainable
Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, Wales, United Kingdom
| | - Ardalan Armin
- Sustainable
Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, Wales, United Kingdom
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28
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Chen Z, Zhu H. Photoinduced Charge Transfer and Recombination Dynamics in Star Nonfullerene Organic Solar Cells. J Phys Chem Lett 2022; 13:1123-1130. [PMID: 35080888 DOI: 10.1021/acs.jpclett.1c04247] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Nonfullerene acceptors (NFAs) are regarded as star candidates for efficient organic solar cells with power conversion efficiency (PCE) over 18%. In contrast to the rapid development of NFA materials, however, the underlying excited-state dynamics which fundamentally govern the device performance remains unclear. In this Perspective, we discuss recent advances and provide our insights on photoinduced charge transfer and combination dynamics in NFA-based organic solar cells (OSCs), including the biphasic hole-transfer process and its correlation with morphology, the role of driving force and Marcus normal region behavior on interfacial hole-transfer properties, and charge recombination energy loss by NFA triplet formation. We also discuss our understanding of how to control the charge-transfer and recombination processes by phase morphology and molecular design to improve OSC performance. Finally, we suggest a few research directions, including the interfacial charge transfer and separation mechanism, the origin of low fill factor, and complex excited-state dynamics in multicomponent OSCs.
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Affiliation(s)
- Zeng Chen
- State Key Laboratory of Modern Optical Instrumentation, Key Laboratory of Excited State Materials of Zhejiang Province, Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Haiming Zhu
- State Key Laboratory of Modern Optical Instrumentation, Key Laboratory of Excited State Materials of Zhejiang Province, Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027, China
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29
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Dai T, Tang A, Wang J, He Z, Li X, Guo Q, Chen X, Ding L, Zhou E. The subtle Structure Modulation of A 2 -A 1 -D-A 1 -A 2 type Nonfullerene Acceptors Extends the Photoelectric Response for High Voltage Organic Photovoltaic Cells. Macromol Rapid Commun 2022; 43:e2100810. [PMID: 35080281 DOI: 10.1002/marc.202100810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 12/19/2021] [Indexed: 11/09/2022]
Abstract
To realize high-voltage organic photovoltaic (OPV) for indoor application and tandem solar cells, both electron-donor and acceptor in the active layer usually adopt wide-bandgap materials. However, the consequent small energy offsets may impede the dissociation of excitons, together with the inadequate light-harvesting, usually leading to the relatively low photocurrent. In this work, we utilize molecular structural modifications to improve the short-circuit current (JSC ) of the high-voltage OPV. With the classic non-fullerene acceptor (NFA), BTA3, as a benchmark, BTA3b contains the linear alkyl chains on the middle core, and JC14 further fuses thiophene ring on BTA unit. We deeply studied the effect of structural modification on broadening the photoelectric response and device performance by using a benzotriazole-based polymer J52-F as donor. The photovoltaic devices based o N J52-F: : BTA3b an D J52-F: : JC14 achieve wider external quantum efficiency (EQE) responses with band edges of 730 and 800 nm respectively, which are about 15 and 85 nm wider than that of the device based o N J52-F: : BTA3. The JSC of the BTA3b and JC14 are accordingly increased to 14.08 and 15.78 mA cm-2 respectively in comparison with BTA3 (11.56 mA cm-2 ). The smaller Urbach energy of 28.16 meV and higher electroluminescence efficiency guarante E J52-F: : JC14 a decreased energy loss (0.528 eV) and a high VOC of 1.07 V. Finally , J52-F: : JC14 combination achieves an increased PCE of 10.33% than that o F J52-F: : BTA3b (PCE = 9.81%) an D J52-F: : BTA3 (PCE = 9.04%). Overall, our research results indicate that subtle structure modification of non-fullerene acceptors, especially introducing fused ring, is a simple and effective strategy to extend the photoelectric response and achieve small energy loss, consequently boosting the JSC and ensuring a high VOC beyond 1.0 V. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Tingting Dai
- CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China.,Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ailing Tang
- CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China
| | - Jiacheng Wang
- Hubei Key Laboratory on Organic and Polymeric Opto-electronic Materials, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China
| | - Zehua He
- CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China.,Henan Institutes of Advanced Technology, Zhengzhou University, Zhengzhou, 450003, China
| | - Xianda Li
- CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China.,Henan Institutes of Advanced Technology, Zhengzhou University, Zhengzhou, 450003, China
| | - Qing Guo
- Henan Institutes of Advanced Technology, Zhengzhou University, Zhengzhou, 450003, China
| | - Xingguo Chen
- Hubei Key Laboratory on Organic and Polymeric Opto-electronic Materials, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China
| | - Liming Ding
- CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China.,Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Erjun Zhou
- CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China.,Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
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30
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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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31
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Liang N, Liu G, Hu D, Wang K, Li Y, Zhai T, Zhang X, Shuai Z, Yan H, Hou J, Wang Z. Heavy-Atom-Free Room-Temperature Phosphorescent Rylene Imide for High-Performing Organic Photovoltaics. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2103975. [PMID: 34813181 PMCID: PMC8787389 DOI: 10.1002/advs.202103975] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 10/23/2021] [Indexed: 06/13/2023]
Abstract
Organic phosphorescence, originating from triplet excitons, has potential for the development of new generation of organic optoelectronic materials. Herein, two heavy-atom-free room-temperature phosphorescent (RTP) electron acceptors with inherent long lifetime triplet exctions are first reported. These two 3D-fully conjugated rigid perylene imide (PDI) multimers, as the best nonfullerene wide-bandgap electron acceptors, exhibit a significantly elevated T1 of ≈2.1 eV with a room-temperature phosphorescent emission (τ = 66 µs) and a minimized singlet-triplet splitting as low as ≈0.13 eV. The huge spatial congestion between adjacent PDI skeleton endows them with significantly modified electronic characteristics of S1 and T1 . This feature, plus with the fully-conjugated rigid molecular configuration, balances the intersystem crossing rate and fluorescence/phosphorescence rates, and therefore, elevating ET1 to ≈2.1 from 1.2 eV for PDI monomer. Meanwhile, the highly delocalized feature enables the triplet charge-transfer excitons at donor-acceptor interface effectively dissociate into free charges, endowing the RTP electron acceptor based organic solar cells (OSCs) with a high internal quantum efficiency of 84% and excellent charge collection capability of 94%. This study introduces an alternative strategy for designing PDI derivatives with high-triplet state-energy and provides revelatory insights into the fundamental electronic characteristics, photophysical mechanism, and photo-to-current generation pathway.
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Affiliation(s)
- Ningning Liang
- College of Physics and OptoelectronicsFaculty of ScienceBeijing University of TechnologyBeijing100124P. R. China
| | - Guogang Liu
- Institute of ChemistryChinese Academy of SciencesBeijing100190P. R. China
| | - Deping Hu
- Key Laboratory of Organic Optoelectronics and Molecular EngineeringDepartment of ChemistryTsinghua UniversityBeijing100084P. R. China
| | - Kai Wang
- Key Laboratory of Luminescence and Optical InformationMinistry of EducationSchool of ScienceBeijing Jiaotong UniversityBeijing100044P. R. China
| | - Yan Li
- Institute of ChemistryChinese Academy of SciencesBeijing100190P. R. China
| | - Tianrui Zhai
- College of Physics and OptoelectronicsFaculty of ScienceBeijing University of TechnologyBeijing100124P. R. China
| | - Xinping Zhang
- College of Physics and OptoelectronicsFaculty of ScienceBeijing University of TechnologyBeijing100124P. R. China
| | - Zhigang Shuai
- Key Laboratory of Organic Optoelectronics and Molecular EngineeringDepartment of ChemistryTsinghua UniversityBeijing100084P. R. China
| | - He Yan
- Department of Chemistry and Energy InstituteHong Kong University of Science and TechnologyClear Water Bay, Kowloon 999077Hong Kong
| | - Jianhui Hou
- Institute of ChemistryChinese Academy of SciencesBeijing100190P. R. China
| | - Zhaohui Wang
- Key Laboratory of Organic Optoelectronics and Molecular EngineeringDepartment of ChemistryTsinghua UniversityBeijing100084P. R. China
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32
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Wang GD, Liu ZX, Qiu BB, Zhang ZG, Wang R, Wang XY, Ma J, Li YF, Xiao M, Zhang CF. Ultrafast electron transfer in all-small-molecule photovoltaic blends promoted by intermolecular interactions in cyanided donors. CHINESE J CHEM PHYS 2021. [DOI: 10.1063/1674-0068/cjcp2109179] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Guo-dong Wang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Zhi-xing Liu
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Bei-bei Qiu
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Zhi-guo Zhang
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- State key Laboratory of Chemical Resource Engineering, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Rui Wang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Xiao-yong Wang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Jing Ma
- Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry of Ministry of Education, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China
| | - Yong-fang Li
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Min Xiao
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, China
- Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Chun-feng Zhang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, China
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Kang H, Zhang X, Xu X, Li Y, Li S, Cheng Q, Huang L, Jing Y, Zhou H, Ma Z, Zhang Y. Strongly Reduced Non-Radiative Voltage Losses in Organic Solar Cells Prepared with Sequential Film Deposition. J Phys Chem Lett 2021; 12:10663-10670. [PMID: 34704764 DOI: 10.1021/acs.jpclett.1c02323] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
With nearly 100% yields for mobile charge carriers in organic solar cells (OSCs), the relatively large photovoltage loss (ΔVoc) is a critical barrier limiting the power conversion efficiency of OSCs. Herein, we aim to improve the open-circuit voltage (Voc) in OSCs with non-fullerene acceptors via sequential film deposition (SD). We show that ΔVoc in planar heterojunction (PHJ) devices prepared by the SD method can be appreciably mitigated, leading increases in Voc to 80 mV with regard to the Voc of bulk heterojunction devices. In PHJ OSCs, the energy level of intermolecular charge-transfer states is found to increase with a decrease in the level of aggregation in the solid state. These properties explain the enhanced electroluminescent quantum efficiency and resultant suppression of the voltage losses induced by nonradiative charge recombination and interfacial charge transfer. This work provides a promising strategy for tackling the heavily discussed photovoltage loss in OSCs.
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Affiliation(s)
- Hui Kang
- School of Chemistry, Beihang University, Beijing 100191, China
| | - Xuning Zhang
- School of Chemistry, Beihang University, Beijing 100191, China
| | - Xiaoyun Xu
- 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, China
| | - Yanxun Li
- National Center for Nanoscience and Technology, Beijing 100191, China
| | - Shilin Li
- School of Chemistry, Beihang University, Beijing 100191, China
| | - Qian Cheng
- National Center for Nanoscience and Technology, Beijing 100191, China
| | - Liqing Huang
- School of Chemistry, Beihang University, Beijing 100191, China
| | - Yanan Jing
- School of Chemistry, Beihang University, Beijing 100191, China
| | - Huiqiong Zhou
- National Center for Nanoscience and Technology, Beijing 100191, 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, China
| | - Yuan Zhang
- School of Chemistry, Beihang University, Beijing 100191, China
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34
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Lee W, Kim H, Lee C, Lee S, Kim T, Kim Y. Performance and Stability of Polymer : Nonfullerene Solar Cells with 100 °C-Annealed Electron-Collecting Combination Layers. CHEMSUSCHEM 2021; 14:3488-3493. [PMID: 34169654 DOI: 10.1002/cssc.202100841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 06/23/2021] [Indexed: 06/13/2023]
Abstract
Inverted-type organic solar cells, fabricated with low-temperature-processed combination layers of hybrid electron-collecting buffer layers (ECBLs) consisting of zinc oxide (ZnO) and poly(2-ethyl-2-oxazoline) (PEOz) and additional PEOz interlayers, showed improved performance and stability. The ZnO : PEOz precursor films with various PEOz compositions (0-12 wt %) were prepared and thermally treated at 100 °C, leading to the ECBLs on which the PEOz interlayers were subsequently deposited before coating of polymer : nonfullerene bulk heterojunction layers. Results showed that the power conversion efficiency of solar cells reached approximately 9.38 and 10.11 % (average) in case of the ZnO/PEOz and ZnO : PEOz(6 wt % PEOz)/PEOz combination layers, respectively, despite the low-temperature thermal annealing process. A continuous irradiation test for 12 h under one sun condition (air mass 1.5G, 100 mW cm-2 ) disclosed that the devices with the ZnO : PEOz(6 wt % PEOz)/PEOz combination layers were more stable than those with the ZnO/PEOz layers.
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Affiliation(s)
- Woongki Lee
- Organic Nanoelectronics Laboratory, KNU Institute for Nanophotonics Applications (KINPA), Department of Chemical Engineering, School of Applied Chemical Engineering, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Hwajeong Kim
- Organic Nanoelectronics Laboratory, KNU Institute for Nanophotonics Applications (KINPA), Department of Chemical Engineering, School of Applied Chemical Engineering, Kyungpook National University, Daegu, 41566, Republic of Korea
- Priority Research Center, Research Institute of Environmental Science & Technology, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Chulyeon Lee
- Organic Nanoelectronics Laboratory, KNU Institute for Nanophotonics Applications (KINPA), Department of Chemical Engineering, School of Applied Chemical Engineering, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Sooyong Lee
- Organic Nanoelectronics Laboratory, KNU Institute for Nanophotonics Applications (KINPA), Department of Chemical Engineering, School of Applied Chemical Engineering, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Taehoon Kim
- Organic Nanoelectronics Laboratory, KNU Institute for Nanophotonics Applications (KINPA), Department of Chemical Engineering, School of Applied Chemical Engineering, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Youngkyoo Kim
- Organic Nanoelectronics Laboratory, KNU Institute for Nanophotonics Applications (KINPA), Department of Chemical Engineering, School of Applied Chemical Engineering, Kyungpook National University, Daegu, 41566, Republic of Korea
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35
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Oh CM, Lee J, Park SH, Hwang IW. Enhanced Charge Separation in Ternary Bulk-Heterojunction Organic Solar Cells by Fullerenes. J Phys Chem Lett 2021; 12:6418-6424. [PMID: 34236208 DOI: 10.1021/acs.jpclett.1c01496] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Carrier generation dynamics in binary PTB7-Th:COi8DFIC (1:1.5) and ternary PTB7-Th:COi8DFIC:PC71BM (1:1.05:0.45) composites were investigated to identify the origins of high power conversion efficiencies (PCEs) in ternary bulk-heterojunction (BHJ) organic solar cells. Steady-state photoluminescence and time-resolved photoinduced absorption spectroscopic analyses revealed that the ternary composite exhibited faster hole transfer from COi8DFIC to PTB7-Th (8 ps compared to 21 ps in the binary composite), which led to an improved exciton separation yield in COi8DFIC (94% compared to 68% in the binary composite). Improved intermixing of the component materials and efficient electron transfer from COi8DFIC to PC71BM facilitated enhancement in the hole transfer rate. The COi8DFIC-to-PC71BM electron transfer promoted an electron transport cascade over PTB7-Th, COi8DFIC, and PC71BM, which efficiently deactivated back-electron transfer (carrier recombination loss) from COi8DFIC to PTB7-Th at ∼160 ps and assisted in improving the PCE of the ternary BHJ cell (13.4% compared to 10.5% in the binary BHJ cell).
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Affiliation(s)
- Chang-Mok Oh
- Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
| | - Jihoon Lee
- Department of Physics, Pukyong National University, Busan 48513, Republic of Korea
| | - Sung Heum Park
- Department of Physics, Pukyong National University, Busan 48513, Republic of Korea
| | - In-Wook Hwang
- Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
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36
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Chow PCY, Chan CCS, Ma C, Zou X, Yan H, Wong KS. Factors That Prevent Spin-Triplet Recombination in Non-fullerene Organic Photovoltaics. J Phys Chem Lett 2021; 12:5045-5051. [PMID: 34019416 DOI: 10.1021/acs.jpclett.1c01214] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Managing the dynamics of spin-triplet electronic states is crucial for achieving high-performance organic photovoltaics. Here we show that the replacement of fullerene with non-fullerene acceptor (NFA) molecules leads to suppression of triplet recombination and thus more efficient charge generation. This indicates that the relaxation of charges to the local triplet exciton state, although energetically allowed, is outcompeted by the thermally activated separation of interfacial charge-transfer excitons (CTEs) in the NFA-based system. By rationalizing our results with Marcus theory, we propose that triplet recombination in the fullerene system is driven by the small energy difference and strong electronic couplings between the CTE state and the lowest-lying triplet exciton state (T1) of fullerene acceptor molecules. In contrast, the large energy difference and small electronic couplings between these states in the NFA-based blends lead to sufficiently slow triplet relaxation rate compared to the charge separation rate (≪1010 s-1), thus preventing triplet recombination.
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Affiliation(s)
- Philip C Y Chow
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam, Hong Kong 999077, China
| | - Christopher C S Chan
- Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China
| | - Chao Ma
- Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China
| | - Xinhui Zou
- Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China
| | - He Yan
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China
| | - Kam Sing Wong
- Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China
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37
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Li P, Fang J, Wang Y, Manzhos S, Cai L, Song Z, Li Y, Song T, Wang X, Guo X, Zhang M, Ma D, Sun B. Synergistic Effect of Dielectric Property and Energy Transfer on Charge Separation in Non-Fullerene-Based Solar Cells. Angew Chem Int Ed Engl 2021; 60:15054-15062. [PMID: 33872454 DOI: 10.1002/anie.202103357] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/18/2021] [Indexed: 11/07/2022]
Abstract
In non-fullerene-based photovoltaic devices, it is unclear how excitons efficiently dissociate into charge carriers under small driving force. Here, we developed a modified method to estimate dielectric constants of PM6 donor and non-fullerene acceptors. Surprisingly, most non-fullerene acceptors and blend films showed higher dielectric constants. Moreover, they exhibited larger dielectric constants differences at the optical frequency. These results are likely bound to reduced exciton binding energy and bimolecular recombination. Besides, the overlap between the emission spectrum of donor and absorption spectra of non-fullerene acceptors allowed the energy transfer from donor to acceptors. Hence, based on the synergistic effect of dielectric property and energy transfer resulting in efficient charge separation, our finding paves an alternative path to elucidate the physical working mechanism in non-fullerene-based photovoltaic devices.
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Affiliation(s)
- Pandeng Li
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, 199 Ren'ai Road, Suzhou, 215123, P. R. China.,Center of Energy, Materials and Telecommunications, Institut National de la Recherche Scientifique (INRS), 1650 Boul. Lionel-Boulet, Varennes, Québec, J3X 1S2, Canada
| | - Jin Fang
- State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, Laboratory of Advanced Optoelectronic Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 199 Ren'ai Road, Suzhou, 215123, P. R. China
| | - Yusheng Wang
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, 199 Ren'ai Road, Suzhou, 215123, P. R. China
| | - Sergei Manzhos
- Center of Energy, Materials and Telecommunications, Institut National de la Recherche Scientifique (INRS), 1650 Boul. Lionel-Boulet, Varennes, Québec, J3X 1S2, Canada
| | - Lei Cai
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, 199 Ren'ai Road, Suzhou, 215123, P. R. China
| | - Zheheng Song
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, 199 Ren'ai Road, Suzhou, 215123, P. R. China
| | - Yajuan Li
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, 199 Ren'ai Road, Suzhou, 215123, P. R. China
| | - Tao Song
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, 199 Ren'ai Road, Suzhou, 215123, P. R. China
| | - Xuechun Wang
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, 199 Ren'ai Road, Suzhou, 215123, P. R. China
| | - Xia Guo
- State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, Laboratory of Advanced Optoelectronic Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 199 Ren'ai Road, Suzhou, 215123, P. R. China
| | - Maojie Zhang
- State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, Laboratory of Advanced Optoelectronic Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 199 Ren'ai Road, Suzhou, 215123, P. R. China
| | - Dongling Ma
- Center of Energy, Materials and Telecommunications, Institut National de la Recherche Scientifique (INRS), 1650 Boul. Lionel-Boulet, Varennes, Québec, J3X 1S2, Canada
| | - Baoquan Sun
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, 199 Ren'ai Road, Suzhou, 215123, P. R. China.,Macao Institute of Materials Science and Engineering, Macau University of Science and Technology, Taipa, 999078, Macau SAR, China
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38
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Li P, Fang J, Wang Y, Manzhos S, Cai L, Song Z, Li Y, Song T, Wang X, Guo X, Zhang M, Ma D, Sun B. Synergistic Effect of Dielectric Property and Energy Transfer on Charge Separation in Non‐Fullerene‐Based Solar Cells. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202103357] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Pandeng Li
- Institute of Functional Nano & Soft Materials (FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices and Collaborative Innovation Center of Suzhou Nano Science and Technology Soochow University 199 Ren'ai Road Suzhou 215123 P. R. China
- Center of Energy, Materials and Telecommunications Institut National de la Recherche Scientifique (INRS) 1650 Boul. Lionel-Boulet Varennes Québec J3X 1S2 Canada
| | - Jin Fang
- State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials Laboratory of Advanced Optoelectronic Materials College of Chemistry, Chemical Engineering and Materials Science Soochow University 199 Ren'ai Road Suzhou 215123 P. R. China
| | - Yusheng Wang
- Institute of Functional Nano & Soft Materials (FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices and Collaborative Innovation Center of Suzhou Nano Science and Technology Soochow University 199 Ren'ai Road Suzhou 215123 P. R. China
| | - Sergei Manzhos
- Center of Energy, Materials and Telecommunications Institut National de la Recherche Scientifique (INRS) 1650 Boul. Lionel-Boulet Varennes Québec J3X 1S2 Canada
| | - Lei Cai
- Institute of Functional Nano & Soft Materials (FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices and Collaborative Innovation Center of Suzhou Nano Science and Technology Soochow University 199 Ren'ai Road Suzhou 215123 P. R. China
| | - Zheheng Song
- Institute of Functional Nano & Soft Materials (FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices and Collaborative Innovation Center of Suzhou Nano Science and Technology Soochow University 199 Ren'ai Road Suzhou 215123 P. R. China
| | - Yajuan Li
- Institute of Functional Nano & Soft Materials (FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices and Collaborative Innovation Center of Suzhou Nano Science and Technology Soochow University 199 Ren'ai Road Suzhou 215123 P. R. China
| | - Tao Song
- Institute of Functional Nano & Soft Materials (FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices and Collaborative Innovation Center of Suzhou Nano Science and Technology Soochow University 199 Ren'ai Road Suzhou 215123 P. R. China
| | - Xuechun Wang
- Institute of Functional Nano & Soft Materials (FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices and Collaborative Innovation Center of Suzhou Nano Science and Technology Soochow University 199 Ren'ai Road Suzhou 215123 P. R. China
| | - Xia Guo
- State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials Laboratory of Advanced Optoelectronic Materials College of Chemistry, Chemical Engineering and Materials Science Soochow University 199 Ren'ai Road Suzhou 215123 P. R. China
| | - Maojie Zhang
- State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials Laboratory of Advanced Optoelectronic Materials College of Chemistry, Chemical Engineering and Materials Science Soochow University 199 Ren'ai Road Suzhou 215123 P. R. China
| | - Dongling Ma
- Center of Energy, Materials and Telecommunications Institut National de la Recherche Scientifique (INRS) 1650 Boul. Lionel-Boulet Varennes Québec J3X 1S2 Canada
| | - Baoquan Sun
- Institute of Functional Nano & Soft Materials (FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices and Collaborative Innovation Center of Suzhou Nano Science and Technology Soochow University 199 Ren'ai Road Suzhou 215123 P. R. China
- Macao Institute of Materials Science and Engineering Macau University of Science and Technology Taipa 999078 Macau SAR China
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39
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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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40
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Bretscher HM, Andrich P, Telang P, Singh A, Harnagea L, Sood AK, Rao A. Ultrafast melting and recovery of collective order in the excitonic insulator Ta 2NiSe 5. Nat Commun 2021; 12:1699. [PMID: 33727541 PMCID: PMC7966769 DOI: 10.1038/s41467-021-21929-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 02/08/2021] [Indexed: 01/05/2023] Open
Abstract
The layered chalcogenide Ta2NiSe5 has been proposed to host an excitonic condensate in its ground state, a phase that could offer a unique platform to study and manipulate many-body states at room temperature. However, identifying the dominant microscopic contribution to the observed spontaneous symmetry breaking remains challenging, perpetuating the debate over the ground state properties. Here, using broadband ultrafast spectroscopy we investigate the out-of-equilibrium dynamics of Ta2NiSe5 and demonstrate that the transient reflectivity in the near-infrared range is connected to the system's low-energy physics. We track the status of the ordered phase using this optical signature, establishing that high-fluence photoexcitations can suppress this order. From the sub-50 fs quenching timescale and the behaviour of the photoinduced coherent phonon modes, we conclude that electronic correlations provide a decisive contribution to the excitonic order formation. Our results pave the way towards the ultrafast control of an exciton condensate at room temperature.
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Affiliation(s)
| | - Paolo Andrich
- Cavendish Laboratory, University of Cambridge, Cambridge, UK.
| | - Prachi Telang
- Department of Physics, Indian Institute of Science Education and Research, Pune, Maharashtra, India
| | - Anupam Singh
- Department of Physics, Indian Institute of Science Education and Research, Pune, Maharashtra, India
| | - Luminita Harnagea
- Department of Physics, Indian Institute of Science Education and Research, Pune, Maharashtra, India
| | - A K Sood
- Department of Physics, Indian Institute of Science, Bangalore, Karnataka, India
| | - Akshay Rao
- Cavendish Laboratory, University of Cambridge, Cambridge, UK.
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