Grain size enlargement and controlled crystal growth by formamidinium chloride additive-added ° ?-CsPbI2Br thin films for stable inorganic perovskite solar cells

Replacing the organic cation with inorganic cation in cesium-based perovskite has fascinated more consideration in halide perovskite solar cells (PSCs) because of their inherent stability and power con-version efficiency (PCE). In the present study, we proposed a new method to increase the stability and PCE of y-CsPbI2Br-based inorganic perovskite solar cells by adding the formamidinium chloride (FACl) additive into the y-CsPbI2Br perovskite precursor solution. The FACl additive shows a significant role in the y-CsPbI2Br perovskite phase to modify the morphology and particular crystal growth to make high -quality perovskite thin films. Also, the FACl additive retards crystallization kinetics to yield a highly crystalline y-CsPbI2Br perovskite phase, comprising enlarged grain size with reduced charge recombi-nation. The optimum amount of FACl (3 mg/ml) additive-added y-CsPbI2Br-based device demonstrated a PCE of 15.03%, which is higher than that of the bare y-CsPbI2Br-based device (12.97%). The stability analysis of the FACl additive-based devices showed high thermal stability that maintains 86% of its initial PCE at 250 h in ambient conditions at 85 degrees C thermal stress.(c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

Replacing the organic cation with inorganic cation in cesium-based perovskite has attracted more attention in halide perovskite solar cells due to their stability and efficiency. In this study, the addition of formamidinium chloride (FACl) was proposed as a method to enhance the stability and efficiency of y-CsPbI2Br-based inorganic perovskite solar cells. The FACl additive played a significant role in modifying the morphology and crystal growth of the perovskite phase, resulting in high-quality perovskite thin films with reduced charge recombination. The optimized FACl additive-added y-CsPbI2Br-based device demonstrated a higher PCE compared to the bare y-CsPbI2Br-based device, and the FACl additive-based devices showed high thermal stability.