Photovoltaic Performance Improvement of All‐Inorganic CsPbBr₃ Perovskite Solar Cells by Antisolvent Assisted Crystallization

Abstract

All‐inorganic CsPbBr3 perovskite solar cells (PSCs) are expected to form semitransparent or top‐cell of tandem solar cells with Cu(In,Ga)Se2 or crystalline silicon solar cells owing to their outstanding environmental tolerance and wide bandgap. However, the commonly solution‐processed CsPbBr3 perovskite films usually suffer from inferior film quality. Herein, we propose antisolvent assisted crystallization method to prepare CsPbBr3 films by multi‐step spin‐coating process. During the spin‐coating step, the underlying PbBr2 layer is treated with anisole antisolvent in different amount of 0, 50, 100, 150, and 200 μl, respectively, and heated at 80 °C for 30 min. Thus, CsPbBr3 films with high crystallinity, less grain boundaries and good coverage are prepared. The champion power conversion efficiency (PCE) of devices based on antisolvent treatment reaches 6.5 %, compared to that of devices without antisolvent treatment (PCE 4.97 %). Moreover, the devices treated with antisolvent without encapsulation exhibit good stability under ambient conditions. The antisolvent assisted crystallization provides an effective route for improving the quality of CsPbBr3 films and promotes the commercialization of all‐inorganic CsPbBr3 PSCs.