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Go E, Jin H, Yoon S, Ahn H, Kim J, Lim C, Kim JH, Din HU, Lee JH, Jun Y, Yu H, Son HJ. Spectrally Resolved Exciton Polarizability for Understanding Charge Generation in Organic Bulk Hetero-Junction Diodes. J Am Chem Soc 2024; 146:14724-14733. [PMID: 38757532 DOI: 10.1021/jacs.4c02361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2024]
Abstract
Despite decades of research, the dominant charge generation mechanism in organic bulk heterojunction (BHJ) devices is not completely understood. While the local dielectric environments of the photoexcited molecules are important for exciton dissociation, conventional characterizations cannot separately measure the polarizability of electron-donor and electron-acceptor, respectively, in their blends, making it difficult to decipher the spectrally different charge generation efficiencies in organic BHJ devices. Here, by spectrally resolved electroabsorption spectroscopy, we report extraction of the excited state polarizability for individual donors and acceptors in a series of organic blend films. Regardless of the donor and acceptor, we discovered that larger exciton polarizability is linked to larger π-π coherence length and faster charge transfer across the heterojunction, which fundamentally explains the origin of the higher charge generation efficiency near 100% in the BHJ photodiodes. We also show that the molecular packing of the donor and acceptor influence each other, resulting in a synergetic enhancement in the exciton polarizability.
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Affiliation(s)
- Enoch Go
- Advanced Photovoltaics Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
- Graduate School of Energy and Environment (KU-KIST GREEN SCHOOL), Korea University, Seoul 02841, Republic of Korea
| | - Hyunjung Jin
- Advanced Photovoltaics Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
- Graduate School of Energy and Environment (KU-KIST GREEN SCHOOL), Korea University, Seoul 02841, Republic of Korea
| | - Seongwon Yoon
- Advanced Photovoltaics Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Hyungju Ahn
- Pohang Accelerator Laboratory, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Joonsoo Kim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Chanwoo Lim
- Advanced Photovoltaics Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Ji-Hee Kim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Department of Physics, Pusan National University, Busan 46241, Republic of Korea
| | - Haleem Ud Din
- Computational Science Research Center, KIST, Seoul 02792, Republic of Korea
| | - Jung-Hoon Lee
- Computational Science Research Center, KIST, Seoul 02792, Republic of Korea
| | - Yongseok Jun
- Graduate School of Energy and Environment (KU-KIST GREEN SCHOOL), Korea University, Seoul 02841, Republic of Korea
| | - Hyeonggeun Yu
- Advanced Photovoltaics Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
- Nanoscience and Technology, KIST School, University of Science and Technology, Seoul 02792, Republic of Korea
| | - Hae Jung Son
- Advanced Photovoltaics Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
- Graduate School of Energy and Environment (KU-KIST GREEN SCHOOL), Korea University, Seoul 02841, Republic of Korea
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2
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Nugraha DF, Son DH, Wardani RP, Lee SW, Whang DR, Kim JH, Chang DW. Strategic structural evolution for enhancing the photovoltaic performance of quinoxaline-based polymers. J IND ENG CHEM 2022. [DOI: 10.1016/j.jiec.2022.07.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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3
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Chen Z, Chen X, Qiu B, Zhou G, Jia Z, Tao W, Li Y, Yang YM, Zhu H. Ultrafast Hole Transfer and Carrier Transport Controlled by Nanoscale-Phase Morphology in Nonfullerene Organic Solar Cells. J Phys Chem Lett 2020; 11:3226-3233. [PMID: 32259443 DOI: 10.1021/acs.jpclett.0c00919] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Nonfullerene acceptors (NFAs) have attracted great attention in high-efficiency organic solar cells (OSCs). While the effect of molecular properties including structures and energetics on charge transfer has been extensively investigated, the effect of macroscopic-phase properties is yet to be revealed. Here we have performed a correlation study of the nanoscale-phase morphology on the photoexcited hole transfer (HT) process and photovoltaic performance by combining ultrafast spectroscopy with high temporal resolution and photo-induced force microscopy (PiFM) with high spatial and chemical resolution. In PM6/IT-4F, we observe biphasic HT behavior with a minor ultrafast (<100 fs) interfacial process and a major diffusion-mediated HT process until ∼100 ps, which depends strongly on phase segregation. Because of the interplay between charge transfer and transport, a compromised domain size of 20-30 nm for NFAs shows the best performance. This study highlights the critical role of phase morphology in high-efficiency OSCs.
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Affiliation(s)
| | | | - Beibei Qiu
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | | | | | | | - Yongfang Li
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
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Zhou Z, Liu W, Zhou G, Zhang M, Qian D, Zhang J, Chen S, Xu S, Yang C, Gao F, Zhu H, Liu F, Zhu X. Subtle Molecular Tailoring Induces Significant Morphology Optimization Enabling over 16% Efficiency Organic Solar Cells with Efficient Charge Generation. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1906324. [PMID: 31815332 DOI: 10.1002/adma.201906324] [Citation(s) in RCA: 117] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 11/12/2019] [Indexed: 05/06/2023]
Abstract
Manipulating charge generation in a broad spectral region has proved to be crucial for nonfullerene-electron-acceptor-based organic solar cells (OSCs). 16.64% high efficiency binary OSCs are achieved through the use of a novel electron acceptor AQx-2 with quinoxaline-containing fused core and PBDB-TF as donor. The significant increase in photovoltaic performance of AQx-2 based devices is obtained merely by a subtle tailoring in molecular structure of its analogue AQx-1. Combining the detailed morphology and transient absorption spectroscopy analyses, a good structure-morphology-property relationship is established. The stronger π-π interaction results in efficient electron hopping and balanced electron and hole mobilities attributed to good charge transport. Moreover, the reduced phase separation morphology of AQx-2-based bulk heterojunction blend boosts hole transfer and suppresses geminate recombination. Such success in molecule design and precise morphology optimization may lead to next-generation high-performance OSCs.
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Affiliation(s)
- Zichun Zhou
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Wenrui Liu
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Guanqing Zhou
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Ming Zhang
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Deping Qian
- Department of Physics, Chemistry and Biology, Linköping University, Linköping, 58183, Sweden
| | - Jianyun Zhang
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Shanshan Chen
- MOE Key Laboratory of Low-grade Energy Utilization Technologies and Systems, CQU-NUS Renewable Energy Materials and Devices Joint Laboratory, School of Energy and Power Engineering, Chongqing University, Chongqing, 400044, China
- Department of Energy Engineering, School of Energy and Chemical Engineering, Perovtronics Research Center, Low Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Shengjie Xu
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Changduk Yang
- Department of Energy Engineering, School of Energy and Chemical Engineering, Perovtronics Research Center, Low Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Feng Gao
- Department of Physics, Chemistry and Biology, Linköping University, Linköping, 58183, Sweden
| | - Haiming Zhu
- Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Feng Liu
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Xiaozhang Zhu
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
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5
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Niu MS, Wang KW, Yang XY, Bi PQ, Zhang KN, Feng XJ, Chen F, Qin W, Xia JL, Hao XT. Hole Transfer Originating from Weakly Bound Exciton Dissociation in Acceptor-Donor-Acceptor Nonfullerene Organic Solar Cells. J Phys Chem Lett 2019; 10:7100-7106. [PMID: 31682127 DOI: 10.1021/acs.jpclett.9b02837] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The underlying hole-transfer mechanism in high-efficiency OSC bulk heterojunctions based on acceptor-donor-acceptor (A-D-A) nonfullerene acceptors (NFAs) remains unclear. Herein, we study the hole-transfer process between copolymer donor J91 and five A-D-A NFAs with different highest occupied molecular orbital energy offsets (ΔEH) (0.05-0.42 eV) via ultrafast optical spectroscopies. Transient absorption spectra reveal a rapid hole-transfer rate with small ΔEH, suggesting that a large energy offset is not required to overcome the exciton binding energy. Capacitance-frequency spectra and time-resolved photoluminescence spectra confirm the delocalization of an A-D-A-structured acceptor exciton with weak binding energy. Relative to the hole-transfer rate, hole-transfer efficiency is the key factor affecting device performance. We propose that holes primarily stem from weakly bound acceptor exciton dissociation, revealing a new insight into the hole-transfer process in A-D-A NFA-based OSCs.
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Affiliation(s)
- Meng-Si Niu
- School of Physics, State Key Laboratory of Crystal Materials , Shandong University , 250100 Jinan , Shandong , China
| | - Kang-Wei Wang
- School of Chemistry, Chemical Engineering and Life Science, State Key Laboratory of Advanced Technology for Materials Synthesis and Processing , Wuhan University of Technology , 430070 Wuhan , Hubei , China
| | - Xiao-Yu Yang
- School of Physics, State Key Laboratory of Crystal Materials , Shandong University , 250100 Jinan , Shandong , China
| | - Peng-Qing Bi
- School of Physics, State Key Laboratory of Crystal Materials , Shandong University , 250100 Jinan , Shandong , China
| | - Kang-Ning Zhang
- School of Physics, State Key Laboratory of Crystal Materials , Shandong University , 250100 Jinan , Shandong , China
| | - Xian-Jin Feng
- School of Microelectronics , Shandong University , 250100 Jinan , Shandong , China
| | - Fei Chen
- Department of Mechanical, Materials and Manufacturing Engineering , The University of Nottingham Ningbo China , Ningbo 315100 , P.R. China
| | - Wei Qin
- School of Physics, State Key Laboratory of Crystal Materials , Shandong University , 250100 Jinan , Shandong , China
| | - Jian-Long Xia
- School of Chemistry, Chemical Engineering and Life Science, State Key Laboratory of Advanced Technology for Materials Synthesis and Processing , Wuhan University of Technology , 430070 Wuhan , Hubei , China
| | - Xiao-Tao Hao
- School of Physics, State Key Laboratory of Crystal Materials , Shandong University , 250100 Jinan , Shandong , China
- ARC Centre of Excellence in Exciton Science, School of Chemistry , The University of Melbourne , Parkville , Victoria 3010 , Australia
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