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3,526 results on '"Li, Yongfang"'

15. Tethered Small‐Molecule Acceptors Simultaneously Enhance the Efficiency and Stability of Polymer Solar Cells

Author

Li, Shangyu, Zhang, Rui, Zhang, Ming, Yao, Jia, Peng, Zhengxing, Chen, Qi, Zhang, Cen, Chang, Bowen, Bai, Yang, Fu, Hongyuan, Ouyang, Yanni, Zhang, Chunfeng, Steele, Julian A, Alshahrani, Thamraa, Roeffaers, Maarten BJ, Solano, Eduardo, Meng, Lei, Gao, Feng, Li, Yongfang, and Zhang, Zhi‐Guo

Subjects
Engineering, Macromolecular and Materials Chemistry, Materials Engineering, Chemical Sciences, Affordable and Clean Energy, device stability, polymer solar cells, tethered small-molecule acceptor, thermodynamically stable, Physical Sciences, Nanoscience & Nanotechnology, Chemical sciences, Physical sciences
Abstract

For polymer solar cells (PSCs), the mixture of polymer donors and small-molecule acceptors (SMAs) is fine-tuned to realize a favorable kinetically trapped morphology and thus a commercially viable device efficiency. However, the thermodynamic relaxation of the mixed domains within the blend raises concerns related to the long-term operational stability of the devices, especially in the record-holding Y-series SMAs. Here, a new class of dimeric Y6-based SMAs tethered with differential flexible spacers is reported to regulate their aggregation and relaxation behavior. In their polymer blends with PM6, it is found that they favor an improved structural order relative to that of Y6 counterpart. Most importantly, the tethered SMAs show large glass transition temperatures to suppress the thermodynamic relaxation in mixed domains. For the high-performing dimeric blend, an unprecedented open circuit voltage of 0.87 V is realized with a conversion efficiency of 17.85%, while those of regular Y6-base devices only reach 0.84 V and 16.93%, respectively. Most importantly, the dimer-based device possesses substantially reduced burn-in efficiency loss, retaining more than 80% of the initial efficiency after operating at the maximum power point under continuous illumination for 700 h. The tethering approach provides a new direction to develop PSCs with high efficiency and excellent operating stability.

Published
2023

39. Recent progress in perovskite solar cells: material science

Author

Shao, Jiang-Yang, Li, Dongmei, Shi, Jiangjian, Ma, Chuang, Wang, Yousheng, Liu, Xiaomin, Jiang, Xianyuan, Hao, Mengmeng, Zhang, Luozheng, Liu, Chang, Jiang, Yiting, Wang, Zhenhan, Zhong, Yu-Wu, Liu, Shengzhong Frank, Mai, Yaohua, Liu, Yongsheng, Zhao, Yixin, Ning, Zhijun, Wang, Lianzhou, Xu, Baomin, Meng, Lei, Bian, Zuqiang, Ge, Ziyi, Zhan, Xiaowei, You, Jingbi, Li, Yongfang, and Meng, Qingbo

Published
2023
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40. Effect of the chlorine substitution position of the end-group on intermolecular interactions and photovoltaic performance of small molecule acceptors

Author

Li, Xiaojun, Angunawela, Indunil, Chang, Yuan, Zhou, Jiadong, Huang, He, Zhong, Lian, Liebman-Pelaez, Alex, Zhu, Chenhui, Meng, Lei, Xie, Zengqi, Ade, Harald, Yan, He, and Li, Yongfang

Subjects
Energy
Abstract

The structure-property relationships of small molecular acceptors (SMAs) are a key issue in the molecular design of new-generation acceptor materials for further improving the device efficiencies of polymer solar cells (PSCs). Herein, three couples of SMA isomers were synthesized, based on three central fused ring units and two 1,1-dicyanomethylene-3-indanone (IC) isomer electron-withdrawing terminal units with chlorine substitutions in different positions of its benzene ring: Cl-1 with chlorine on the same side as a CO group of IC and Cl-2 with chlorine on the same side as the CN groups of IC. Through systematical investigation, we found that the chlorine substitution position of the terminal groups has a regular and significant influence on the molecular packing and photovoltaic performance of the SMAs. The molecular packing behavior of the SMAs is closely related to and determined by the configuration of their terminal groups, no matter which central fused ring of the SMAs is used. In particular, the Cl-1-based SMAs possess a stronger crystallinity with long range ordering packing in their molecular plane direction, while the more abundant and stereoscopic π-π intermolecular interaction in the Cl-2-based SMAs promotes the molecules to form three-dimensional charge transporting channels and leads to their red-shifted absorption and higher electron mobilities. Therefore, the Cl-2-based PSCs exhibit a higher power conversion efficiency (PCE) compared to that of the Cl-1-based devices, and the best PCE of a Cl-2 SMA-based PSC reached 16.42%. These results highlight the importance of the investigation of intermolecular interactions, packing and the arrangement of the SMAs in the solid-state, which may provide direct insights for exploring the relationship between the molecular structure and property of the photovoltaic materials. Moreover, we envision that if fragments such as end groups or side chains with more diverse molecular interactions are added into the design and the subsequent synthesis of the SMAs, this may be beneficial to promoting molecular π-π accumulation and further improving the molecular order, forming suitable molecular packing and morphology in the resulting blend films, and finally affecting the efficiency of the PSCs. This journal is

Published
2020

41. Recent progress in perovskite solar cells: from device to commercialization

Author

Luo, Xinhui, Lin, Xuesong, Gao, Feng, Zhao, Yang, Li, Xiaodong, Zhan, Liqing, Qiu, Zexiong, Wang, Jin, Chen, Cong, Meng, Lei, Gao, Xiaofeng, Zhang, Yu, Huang, Zijian, Fan, Rundong, Liu, Huifen, Chen, Yanrun, Ren, Xiaoxue, Tang, Jiahong, Chen, Chun-Hao, Yang, Dong, Tu, Yongguang, Liu, Xiao, Liu, Dongxue, Zhao, Qing, You, Jingbi, Fang, Junfeng, Wu, Yongzhen, Han, Hongwei, Zhang, Xiaodan, Zhao, Dewei, Huang, Fuzhi, Zhou, Huanping, Yuan, Yongbo, Chen, Qi, Wang, Zhaokui, Liu, Shengzhong Frank, Zhu, Rui, Nakazaki, Jotaro, Li, Yongfang, and Han, Liyuan

Published
2022
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