Cai Yunhao, Zhang Huotian, Ye Linglong, Zhang Rui, Xu Jinqiu, Zhang Kangning, Bi Pengqing, Li Tengfei, Weng Kangkang, Xu Ke, Xia Jianlong, Bao Qinye, Liu Feng, Hao Xiaotao, Tan Songting, Gao Feng, Zhan Xiaowei, Sun Yanming
School of Chemistry, Beihang University, Beijing 100191, P. R. China.
Department of Physics, Chemistry, and Biology, Linköping University, Linköping 58183, Sweden.
ACS Appl Mater Interfaces. 2020 Sep 30;12(39):43984-43991. doi: 10.1021/acsami.0c13085. Epub 2020 Sep 21.
The energy offset, considered as the driving force for charge transfer between organic molecules, has significant effects on both charge separation and charge recombination in organic solar cells. Herein, we designed material systems with gradually shifting energy offsets, including both positive and negative values. Time-resolved spectroscopy was used to monitor the charge dynamics within the bulk heterojunction. It is striking to find that there is still charge transfer and charge generation when the energy offset reached -0.10 eV (ultraviolet photoelectron spectroscopy data). This work not only indicates the feasibility of the free carrier generation and the following charge separation under the condition of a negative offset but also elucidates the relationship between the charge transfer and the energy offset in the case of polymer chlorination.
能量偏移被视为有机分子间电荷转移的驱动力，对有机太阳能电池中的电荷分离和电荷复合均有显著影响。在此，我们设计了能量偏移逐渐变化的材料体系，包括正值和负值。利用时间分辨光谱监测本体异质结内的电荷动力学。令人惊讶的是，当能量偏移达到-0.10 eV（紫外光电子能谱数据）时，仍存在电荷转移和电荷产生。这项工作不仅表明了在负偏移条件下自由载流子产生及后续电荷分离的可行性，还阐明了聚合物氯化情况下电荷转移与能量偏移之间的关系。
