Small molecule donors with different conjugated π linking bridges:Synthesis and photovoltaic propert

• 作 者: Xiyue Dong Dingqin Hu Pengyu Chen Xuexin Dai Chao Hu Zeyun Xiao Shirong Lu
• 机 构: Organic Semiconductor Research Center,Chongqing Institute of Green and Intelligent Technology,Chongq
• 出 处: 半导体学报（英文版）
• 发表日期: 2020年12期
• 关键词: organic solar cell small molecule donor molecule energy levels morphology

Three small molecule (SM) donors,namely B-T-CN,B-TT-CN and B-DTT-CN,with different π conjugated bridges were synthesized in this research.Interestingly,with the conjugated fused rings of the π linking bridge increasing,the SM HOMO levels exhibit a decline tendency with-5.27 eV for B-T-CN,-5.31 eV for B-TT-CN and-5.40 eV for B-DTT-CN.After blending the SM donors with the fullerene acceptor PC71BM,the all SM organic solar cells (OSCs) achieved high Vocs of 0.90 to 0.96 V.However,the phase separation morphology and molecule stacking are also unexpectedly changed together with the enhancement of conjugated degree of π bridges,resulting in a lower power conversion efficiency (PCE) for the B-DTT-CN:PC71BM device.Our results demonstrate and provide a useful way to enhance OSC Voc and the morphology needs to be further optimized.