Thiophene–Arylamine Hole-Transporting Materials in Perovskite Solar Cells: Substitution Position Effect

Two facile thiophene–arylamine hole-transporting materials, obtained by varying the substitution position of arylamine moieties on the thiophene π linker, are reported. The substitution position effect of two hole-transporting materials on the performance of perovskite solar cells is further investigated theoretically and experimentally. The compound in which arylamine moieties are located on the 2,5-substitution position of thiophene shows better conjunction than that with the 3,4-substituent. When used as hole-transporting materials in CH₃NH₃PbI₃-based solar cells, the 2,5-substituent exhibits a power conversion efficiency (PCE) of 15.13 %, which is over 40 % higher than that of the 3,4-substituent. Moreover, the PCE of 2,5-substituent based device is comparable with that of 2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenylamine)-9,9′-spirobifluorene (spiro-OMeTAD).