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)₂PbI₄ or (FPEA)₂PbI₄ 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 moisture-induced 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.