Novel D-π-A organic sensitizers containing diarylmethylene-bridged triphenylamine and different spacers for solar cell application

Abstract

Bridged triphenylamine having almost planar core structure is a potential donor moiety for DSSCs. In this work, three novel D-π-A organic dyes TB-1, TB-2, and TB-3, containing diarylmethylene-bridged triphenylamine as the donor moiety, cyanoacrylic acid as the acceptor, and thiophene, benzene or furan as the π-spacers were synthesized and characterized for applications in dye-sensitized solar cells (DSSCs). Their photophysical, electrochemical, and photovoltaic properties were investigated, the performance of the triphenylamine donor was compared, and the effect of different π-spacers was evaluated. Results demonstrated that compared to the nonplanar triphenylamine donor, the more planar bridged TPA could offer better charge transfer process and as a result higher performances. On the other hand, in these compounds, both thiophene and furan linkages show better planarization and electron delocalization compared to the benzene linkage in this molecular system. Accordingly, dye TB-1 and TB-3 show higher IPCE and Jsc values. Considering the larger Voc of dye TB-3, therefore it outperforms the other two sensitizers, exhibiting power conversion efficiency of 3.81%, with Jsc of 7.54mAcm−2 and Voc of 725mV under simulated AM 1.5 irradiation (100mWcm−2). The results are further confirmed by the EIS experiments.