Ambipolar-transport wide-bandgap perovskite interlayer for organic photovoltaics with over 18% efficiency

Anode interface layers (AILs) are of vital importance to the performance of organic photovoltaics (OPVs). Herein, MAPbBr₃ is firstly demonstrated as an effective solution-processed AIL, featuring a 2.3-eV bandgap and high hole and electron mobility. PM6:BO-4Cl based on unannealed device with the MAPbBr₃ AIL exhibits an encouraging efficiency of 15.5%. F4TCNQ is further doped into MAPbBr₃ to increase work function and passivate defects, boosting the efficiency to 17.3%. Likewise, the unannealed devices based on PM6:BTP-eC9:PC₇₁BM achieved a high efficiency of 18.3% with the MAPbBr₃/F4TCNQ AIL. The ambipolar ability of MAPbBr₃ in OPVs was further proved by inverted devices. Therefore, MAPbBr₃ successfully serves multiple functions: a down-conversion layer, an energy donor, and a textured seeding layer influencing bulk-heterojunction (BHJ) morphology. This finding successfully demonstrates the practicability of wide-bandgap perovskite materials as highly promising OPV interfacial materials.