Hysteresis-free two-dimensional perovskite solar cells prepared by single-source physical vapour deposition

Hysteresis-free two-dimensional (2D) pervoskite solar cells are prepared by single-source physical vapour deposition (SSPVD). The (BA)2(MA)3Pb4I13 2D perovskite films are prepared by thermal evaporating their crystal powder and post-annealing. The dense and uniform films are formed on the surface, with high crystallization and full surface coverage. Especially, these films exhibit good chemical accordance with the precursors and optical properties. A photovoltaic efficiency of approximately 4.5% with no hysteresis was obtained for (BA)2(MA)3Pb4I13 solar cells fabricated by SSPVD. These initial results suggest that single-source physical vapour deposition is a promising method for preparing high-quality complicated multi-cation 2D perovskite films for solar application.