Growth control and defect passivation toward efficient and low-temperature processed carbon based CsPbIBr₂ solar cell

All-inorganic perovskite CsPbIBr₂, has drawn much attention for photovoltaic (PV) application due to its excellent intrinsic stability. However, low device performance and high fabrication temperature still hamper its further progress in flexible application. Herein, Zn substitution has been used to improve the nucleation and growth process for low temperature processed a-phase CsPbIBr₂ film. Zn incorporated CsPbIBr₂ film exhibits good crystallinity, compact surface morphology and depressed defect state. Low temperature (100 °C and 160 °C) processed carbon based CsPbIBr₂ solar cells with improved PV performance have been prepared by using Zn incorporation and room deposited electron transport layer (ETL). A champion efficiency over 9% can be achieved through Zn substitution, which is one of the best values reported for the low temperature processed CsPbIBr₂ solar cell without using hole transport layer (HTL). Efficiency over 5% can also be achieved for larger area (1 cm²) rigid and flexible CsPbIBr₂ solar cells. These results would provide a new route for preparing high-performance and low temperature processed inorganic perovsktie solar cell.