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Zhang L, Sun R, Zhang Z, Zhang J, Zhu Q, Ma W, Min J, Wei Z, Deng D. Donor End-Capped Alkyl Chain Length Dependent Non-Radiative Energy Loss in All-Small-Molecule Organic Solar Cells. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2207020. [PMID: 36263872 DOI: 10.1002/adma.202207020] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 09/22/2022] [Indexed: 06/16/2023]
Abstract
A critical bottleneck for further efficiency breakthroughs in organic solar cells (OSCs) is to minimize the non-radiative energy loss (eΔVnr ) while maximizing the charge generation. With the development of highly emissive low-bandgap non-fullerene acceptors, the design of high-performance donors becomes critical to enable the blend with the electroluminescence quantum efficiency to approach or surpass the pristine acceptor. Herein, by shortening the end-capped alkyl chains of the small-molecular donors from hexyl (MPhS-C6) to ethyl (MPhS-C2), the material obtained aggregation that was insensitive to thermal annealing (TA) along with condensed packing simultaneously. The former leads to small phase separation and suppressed upshifts of the highest occupied molecular orbital energy level during TA, and the latter facilitates its efficient charge-transport at aggregation-less packing. Hence, the ΔVnr decreases from 0.242 to 0.182 V, from MPhS-C6 to MPhS-C2 based OSCs. An excellent PCE of 17.11% is obtained by 1,8-diiodoctane addition due to almost unchanged high Jsc (26.6 mA cm-2 ) and Voc (0.888 V) with improved fill factor, which is the record efficiency with the smallest energy loss (0.497 eV) and ΔVnr (0.192 V) in all-small-molecule OSCs. These results emphasize the potential material design direction of obtaining concurrent TA-insensitive aggregation and condensed packing to maximize the device performances with a super low ΔVnr .
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Affiliation(s)
- Lili Zhang
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
- Sino-Danish Center for Education and Research, Sino-Danish College, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Rui Sun
- The Institute for Advanced Studies, Wuhan University, Wuhan, 430072, P. R. China
| | - Ziqi Zhang
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
| | - Jianqi Zhang
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
| | - Qinglian Zhu
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, P. R. China
| | - Wei Ma
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, P. R. China
| | - Jie Min
- The Institute for Advanced Studies, Wuhan University, Wuhan, 430072, P. R. China
| | - Zhixiang Wei
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
| | - Dan Deng
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
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Zheng B, Yue Y, Ni J, Sun R, Min J, Wang J, Jiang L, Huo L. An end-capped strategy for crystalline polymer donor to improve the photovoltaic performance of non-fullerene solar cells. Sci China Chem 2022. [DOI: 10.1007/s11426-021-1205-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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