Novel hole transporting materials with a linear pi-conjugated structure for highly efficient perovskite solar cells

Novel small-molecule hole transporting materials (HTMs) with a linear pi-conjugated structure have been synthesized. The perovskite solar cell based on 2TPA-2-DP as the HTM exhibits an encouraging power conversion efficiency of 9.1% under AM 1.5 G (100 mW cm(-2)) illumination, which is the first demonstration of an effective perovskite solar cell using a linear structured HTM.