High‐Efficiency Solution‐Processed Planar Perovskite Solar Cells with a Polymer Hole Transport Layer

A high-efficiency solution-processed inverted perovskite solar cell with poly[N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)benzidine] (poly-TPD) as the hole transport layer is demonstrated. The perovskite forms large crystallites on poly-TPD, yielding devices with an average power conversion efficiency of 13.8% and a maximum of 15.3%.