标题：Effects of various donor:acceptor blend ratios on photophysical properties in non-fullerene organic bulk heterojunctions
作者：Wen, Zhenchuan; Ma, Xuejian; Yang, Xiaoyu; Bi, Pengqing; Niu, Mengsi; Zhang, Kangning; Feng, Lin; Hao, Xiaotao
作者机构：[Wen, Zhenchuan; Ma, Xuejian; Yang, Xiaoyu; Bi, Pengqing; Niu, Mengsi; Zhang, Kangning; Feng, Lin; Hao, Xiaotao] Shandong Univ, State Key Lab Crystal 更多
通讯作者地址：[Hao, XT]Shandong Univ, State Key Lab Crystal Mat, Sch Phys, Jinan 250100, Shandong, Peoples R China.
来源：CHINESE CHEMICAL LETTERS
关键词：Photophysical properties; Non-fullerene; Bulk heterojunctions; Various; blend ratios; Organic solar cells
摘要：The composition ratio of donor and acceptor materials in organic bulk heterojunction (BHJ) is one of the key parameters to govern the performance in organic solar cells (OSCs). Therefore, high-performance non-fullerene organic bulk heterojunction consisting of poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene))-co-(1,3-di(5-thiophene-2-yl)-5,7-bis(2-ethylhexyl) benzo[1,2-c:4,5-e]clithiophene-4,8-dione)] (PBDB-T) and 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2',3'-d']-s-indaceno[1,2-b:5,6-bq-dithio-phene (ITIC) are used to investigate the correlation among various donor: acceptor (D:A) ratios, photophysical properties and photovoltaic performance. Interestingly, the function of short-circuit current (J(sc)) and D:A ratios demonstrates an axisymmetric trend. When the blending ratio of D:A deviates from the optimal ratio, the symmetrically decreased J(sc) is derived from a reduction in the D:A interface or amorphous region. Research on the steady-state photoluminescence (PL), the time-resolved fluorescence spectroscopy measurements, atomic force microscopic (AFM) and grazing-incidence small angle X-rays scattering (GIWAXS) indicates no significant variation in energy loss in the process of changing D:A ratios in BHJs. With high donor or acceptor content, the domain size improves significantly, but the distance of pi-pi stacking corresponding to molecular packing has not changed significantly, and the bi-continuous percolation pathways were not obviously influenced. (C) 2019 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.