Tetrathienoanthracene and Tetrathienylbenzene Derivatives as Hole‐Transporting Materials for Perovskite Solar Cell

The synthesis and characterization of two related families of star‐shaped thiophene‐containing hole‐transporting materials (HTMs) based on fused tetrathienoanthracene and nonfused tetrathienylbenzene cores are reported. All of them are endowed with four terminal (4,4′‐dimethoxy)diphenylamino groups that are either linked directly to the core or showed a different type of bridges (i.e., thiophene‐phenyl or phenyl rings). The novel HTMs are tested in mixed‐ion perovskite (Cs0.1FA0.74MA0.13PbI2.48Br0.39) solar cells, and power conversion efficiencies of up to 18.8% are measured under 1 sun irradiation, comparable with the efficiency obtained for the reference cell using 2,2′,7,7′‐tetrakis(N,N′‐di‐p‐methoxyphenylamine)‐9,9′‐spirobifluorene as an HTM. Two related families of star‐shaped thiophene‐containing small molecules based on fused tetrathienoanthracene and nonfused tetrathienylbenzene cores are tested as hole‐transporting materials (HTMs) in mixed‐ion perovskite solar cells (PSCs). The best‐tested HTM, TTA3, reach a similar power conversion efficiency (PCE) in PSC to the standard Spiro‐OMeTAD, with maxima PCE of 18.8% under simulated 1 sun illumination (AM1.5G).