Feasible D1–A–D2–A Random Copolymers for Simultaneous High‐Performance Fullerene and Nonfullerene Solar Cells |
| |
| Authors: | Mingyu Jeong Shanshan Chen Sang Myeon Lee Zhiwei Wang Yankang Yang Zhi‐Guo Zhang Chunfeng Zhang Min Xiao Yongfang Li Changduk Yang |
| |
| Affiliation: | 1. 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), Ulju‐gun, Ulsan, South Korea;2. National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China;3. Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China |
| |
| Abstract: | A series of PBDB‐TTn random donor copolymers is synthesized, consisting of an electron‐deficient benzo[1,2‐c:4,5‐c′]dithiophene‐4,8‐dione (BDD) unit and different ratios of two electron‐rich benzo[1,2‐b:4,5‐b′]dithiophene (BDT) and thieno[3,2‐b]thiophene (TT) units, with intention to modulate the intrachain and/or interchain interactions and ultimately bulk‐heterojunction morphology evolution. A comparative study using 4 × 2 polymer solar cell (PSC) performance maps and each of the [6,6]‐phenyl‐C71‐butyric acid methyl ester (PC71BM) and the fused‐aromatic‐ring‐based molecule (m‐ITIC) acceptors are carried out. Given the similarities in their absorption ranges and energy levels, the PBDB‐TTn copolymers clearly reveal a change in the absorption coefficients upon optimization of the BDT to TT ratio in the backbone. Among the given acceptor combination sets, superior performances are observed in the case of PBDB‐TT5 blended with PC71BM (8.34 ± 0.10%) or m‐ITIC (11.10 ± 0.08%), and the dominant factors causing power conversion efficiency differences in them are found to be distinctly different. For example, the performances of PC71BM‐based PSCs are governed by size and population of face‐on crystallites, while intermixed morphology without the formation of large phase‐separated aggregates is the key factor for achieving high‐performance m‐ITIC‐based PSCs. This study presents a new sketch of structure–morphology–performance relationships for fullerene‐ versus nonfullerene‐based PSCs. |
| |
| Keywords: | compatibility fullerene solar cells nonfullerene solar cells random copolymer structure– property relationship |
|
|
