Broadly Applicable Synthesis of Heteroarylated Dithieno[3,2-b:2’,3’-d]pyrroles for Advanced Organic Materials – Part 2: Hole-transporting Materials for Perovskite Solar Cells

Functionalization of heteroarylated dithieno[3,2-b:2’,3’-d]pyrroles (DTP) by triarylamines was elaborated to result in novel hole transport materials (HTMs) for perovskite solar cells. The new HTMs showed promising photovoltaic performance with efficiencies exceeding 18%. A thorough investigation of the electronic and opto-electronic properties revealed that the main efficiency loss mechanisms are not related to the pristine HTM materials but to the suboptimal interface passivation and HTM doping. We provide an optimization strategy for those device fabrication factors, which could render these new materials a potential replacement of current state-of-the-art HTMs.