CuSCN as Hole Transport Material with 3D/2D Perovskite Solar Cells

We report stable perovskite solar cells having 3D/2D perovskite absorber layers and CuSCN as an inorganic hole transporting material (HTM). (Phenylethyl)ammonium (PEA) and [(4-fluorophenyl)ethyl]ammonium (FPEA) have been chosen as 2D cations, creating thin layers of (PEA)(2)PbI4 or (FPEA)(2)PbI4 on top of the 3D perovskite. The 2D perovskite as an interfacial layer, neutralizes defects at the surface of the 3D perovskite absorber, and can protect from moistureinduced degradations. We demonstrate excellent charge extraction through the modified interfaces into the inorganic CuSCN HTM, with device efficiencies above 18%, compared to 19.3% with conventional spiro-OMeTAD. Furthermore, we show significantly enhanced ambient stability.