Simple Triphenylamine-Based Hole-Transporting Materials for Perovskite Solar Cells

We report two simple triphenylamine-based hole-transporting materials (HTMs) containing vinyl derivatives, 3,6-di(2-(4-(N,N-di(p-tolyl)amino)phenyl)vinyl)-2-thiophene (apv-T) and 3,6-di(2-(4-(N,N-di(p-tolyl)amino)phenyl)vinyl)-9-ethyl-carbazole (apv-EC) for the perovskite solar cells. According to theoretical calculation and experimental results, their HOMO energy levels are similar to that of conventional spiro -OMeTAD, which is supposed to be favorable for the hole transportation in the device. Up to 12% of light-to-electricity conversion efficiency has been achieved for the mesoporous TiO 2 /CH 3 NH 3 PbI 3 /apv-EC/Au solar cell without using p -type dopants. Time-resolved photoluminescence (PL) measurement and Electrochemical Impedance Spectra (EIS) further reveal that relatively high hole mobility of the apv-EC and weak recombination occurred at TiO 2 /CH 3 NH 3 PbI 3 /apv-EC interfaces of the device are crucial to the good performance in comparison with the apv-T. Advantages such as easy synthesis, low cost and relatively good cell performance provide a potential application as the replacement of the expensive spiro -OMeTAD.