Su Wenyan, Wang Yang, Yin Zhihong, Fan Qunping, Guo Xia, Yu Liyang, Li Yuxiang, Hou Lintao, Zhang Maojie, Peng Qiang, Li Yongfang, Wang Ergang
Guangzhou Key Laboratory of Vacuum Coating Technologies and New Energy Materials, Siyuan Laboratory, Department of Physics, Jinan University, Guangzhou, 510632, P. R. China.
Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Göteborg, 412 96, Sweden.
ChemSusChem. 2021 Sep 6;14(17):3535-3543. doi: 10.1002/cssc.202100860. Epub 2021 Jun 19.
How to simultaneously achieve both high open-circuit voltage (V ) and high short-circuit current density (J ) is a big challenge for realising high power conversion efficiency (PCE) in all-small-molecule organic solar cells (all-SM OSCs). Herein, a novel small molecule (SM)-donor, namely FYSM-SiCl, with trialkylsilyl and chlorine substitutions was designed and synthesized. Compared to the original SM-donor FYSM-H, FYSM-Si with trialkylsilyl substitution showed a decreased crystallinity and lower highest occupied molecular orbital (HOMO) level, while FYSM-SiCl had an improved crystallinity, more ordered packing arrangement, significantly lower HOMO level, and predominant "face-on" orientation. Matched with a SM-acceptor Y6, the FYSM-SiCl-based all-SM OSCs exhibited both high V of 0.85 V and high J of 23.7 mA cm , which is rare for all-SM OSCs and could be attributed to the low HOMO level of FYSM-SiCl donor and the delicate balance between high crystallinity and suitable blend morphology. As a result, FYSM-SiCl achieved a high PCE of 13.4 % in all-SM OSCs, which was much higher than those of the FYSM-H- (10.9 %) and FYSM-Si-based devices (12.2 %). This work demonstrated a promising method for the design of efficient SM-donors by a side-chain engineering strategy via the introduction of trialkylsilyl and chlorine substitutions.
对于全小分子有机太阳能电池（all-SM OSCs）而言，如何同时实现高开路电压（V ）和高短路电流密度（J ）是实现高功率转换效率（PCE）的一大挑战。在此，设计并合成了一种新型小分子（SM）供体，即带有三烷基硅基和氯取代基的FYSM-SiCl。与原始的SM供体FYSM-H相比，带有三烷基硅基取代的FYSM-Si结晶度降低，最高占据分子轨道（HOMO）能级降低，而FYSM-SiCl结晶度提高，堆积排列更有序，HOMO能级显著降低，且呈现出主要的“面朝上”取向。与SM受体Y6匹配时，基于FYSM-SiCl的全小分子有机太阳能电池表现出0.85 V的高V 和23.7 mA cm 的高J ，这在全小分子有机太阳能电池中较为罕见，这可归因于FYSM-SiCl供体的低HOMO能级以及高结晶度与合适的共混形态之间的微妙平衡。结果，FYSM-SiCl在全小分子有机太阳能电池中实现了13.4 %的高PCE，远高于基于FYSM-H（10.9 %）和FYSM-Si的器件（12.2 %）。这项工作展示了一种通过引入三烷基硅基和氯取代基的侧链工程策略来设计高效SM供体的有前景的方法。
