高性能D-π-A型三芳胺类光敏染料的理论设计和表征

Theoretical design and characterization of high performance triphenylamine-based D-π-A sensitizer

基于密度泛函理论(DFT)以及含时密度泛函理论(TDDFT)计算,系统研究了具有不同π桥(环戊联噻吩T和二萘嵌苯P)和受体(氰基丙烯酸CA、苯并噻二唑-苯甲酸BTBA和乙炔基苯并噻二唑-苯甲酸EBTBA)的6个D-π-A芳胺类染料分子的几何和电子结构、吸收光谱、电子注入寿命、染料吸附后导带能级的移动以及电子复合速率等性质.计算结果表明,除TPA-P-BTBA分子外,其余分子均展现出可以与TPA-T-CA(C218)相媲美甚至超越的光捕获能力;所有染料的电子注入寿命均在飞秒(fs)尺度上,展现出超快的电子注入速率;染料吸附之后所引起的TiO_2半导体导带能级移动均为0.25 eV左右,有利于开路电压(V_OC)的提高.重要的是,对于电子复合速率,TPA-T-CA约是TPA-T-EBTBA和TPA-P-EBTBA的44倍,是TPA-T-BTBA的11倍,因此推测,TPA-P-EBTBA、TPA-T-EBTBA以及TPA-T-BTBA将具有更高的短路电流、开路电压和效率,将成为染料敏化太阳能电池(DSSC)

The geometries,electronic structures,absorption spectra,electron injections,conduction band energy shift and charge recombination process of six organic sensitizers used for dye sensitized solar cells were investigated in this work through density functional theory and time-dependent density functional theory calculations.The results demonstrated that all the molecules show comparable light harvesting ability as compared to TPA-T-CA except for TPA-P-BTBA.And the electron injection life of all dyes is on femtosecond（fs） scale,showing ultrafast electron injection rate.Moreover,as for the charge recombination process,TPA-T-CA is about 44 times larger than that of TPA-T-EBTBA and TPA-P-EBTBA,and 11 times larger than that of TPA-T-BTBA.Thus,we predict that TPA-PEBTBA,TPA-T-EBTBA and TPA-T-BTBA could show larger J_SC,V_OC and therefore the overall efficiency,which could make them as the promising candidates of DSSC.