Modulation of terminal alkyl chain length enables over 15% efficiency in small-molecule organic solar cells  

作　　者：Qianglong Lv Cunbin An Tao Zhang Jianqi Zhang Shaoqing Zhang Pengxin Zhou Chang He Jianhui Hou 

机构地区：[1]Beijing National Laboratory for Molecular Sciences,State Key Laboratory of Polymer Physics and Chemistry,Institute of Chemistry,Chinese Academy of Sciences,Beijing 100190,China [2]College of Chemistry and Chemical Engineering,Northwest Normal University,Lanzhou 730070,China [3]Key Laboratory of Nanosystem and Hierarchical Fabrication,National Center for Nanoscience and Technology,Beijing 100190,China [4]University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Science China Chemistry》2021年第7期1200-1207,共8页中国科学（化学英文版）

基　　金：supported by the National Natural Science Foundation of China(21734008,21835006,51873217);Beijing National Laboratory for Molecular Sciences(BNLMS-CXXM-201903)。

摘　　要：In small-molecule organic solar cells(SM-OSCs),it remains a big challenge to obtain favorable bulk heterojunction morphology by donor material design.Herein,we design and synthesize three small-molecule donors BPF3T-C4,BPF3T-C6 and BPF3T-C8,with different terminal alkyl chains.Although they possess similar absorption profiles and molecular energy levels,their crystallinity gradually decreases with the chain length of the terminal alkyl chains.After blending with an electron acceptor of BO-4Cl,the crystallinity is suppressed and the packing orientations of these donors changed from edge-on to face-on.Simultaneously,the crystallinity of BO-4Cl is gradually weakened with the chain length of the terminal alkyl chain of donor materials.Finally,The BPF3T-C6 with moderate crystallinity exhibits the best phase-separation morphology among these blend films.As a result,the BPF3T-C6:BO-4Cl-based SM-OSC shows an impressive power conversion efficiency of 15.1%.

关 键 词：small-molecule donor non-fullerene acceptor intermolecular interaction terminal alkyl chain small-molecule organic solar cells 

分 类 号：TM914.4[电气工程—电力电子与电力传动] TB383.2[一般工业技术—材料科学与工程]