摘要
Three small molecule(SM)donors,namely B-T-CN,B-TT-CN and B-DTT-CN,with differentπconjugated bridges were synthesized in this research.Interestingly,with the conjugated fused rings of theπlinking 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 ofπbridges,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.
基金
This work was supported by National Natural Science Foundation of China(21801238)
National Youth Thousand Program Project(R52A199Z11)
CAS Pioneer Hundred Talents Program B(Y92A010Q10)
Organic Semiconductor Center of Chongqing Institute of Green and Intelligent Technology,Chinese Academy of Sciences.
