Moderate Hot Antisolvent Treatment for Efficient 2D Alternating Cation Perovskite Solar Cells

Two-dimensional (2D) perovskites are rising as promising photoelectric materials for solar cells, due to their excellent environment stability compared to their 3D counterparts. However, the power conversion efficiency (PCE) of 2D perovskite solar cells (PVSCs) still lags far behind those of the 3D PVSCs. We report here on a 2D PVSCs employing an alternating cation (ACI)-type perovskite (GA)(MA) n Pb n I 3n+1 (n = 5)) with a PCE over 18%, which is achieved by moderate control of antisolvent temperature. An optimal antisolvent temperature improves perovskite film morphology, enhances crystallinity, reduces defect density, and thus suppresses charge carrier nonradiative recombination, which eventually results in a champion PCE of 18.92% with decreased hysteresis and increased reproducibility. This work provides a facile and effective strategy for the quality control of 2D perovskite films towards efficient PVSCs.