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). Right move: Two new hole‐transporting materials (HTMs) with substituents in different positions are investigated. The 2,5‐substituent shows significantly better performance than that of the 3,4‐substituent in a perovskite solar cell; the former is comparable to that of 2,2′,7,7′‐tetrakis(N,N‐di‐p‐methoxyphenylamine)‐9,9′‐spirobifluorene (spiro‐OMeTAD).