Open Circuit Voltage Enhancement and Defect Suppression of Wide-Bandgap CsPbIBr ₂ Perovskite Solar Cells by Phenylhydrazinium Chloride Incorporation

Wide-bandgap (WBG) perovskite solar cells possess huge potential for integration into next-generation heterojunction photovoltaic systems. Conversely, their well-known commercialization is presently hindered by several challenges, including considerable open circuit voltage losses and poor long-term stability. Here, we report phenylhydrazinium chloride (PCl) as an effective dopant in WBG CsPbIBr₂ perovskite solar cells, which inhibits halide oxidation and demixing in addition to decreasing defect density, leading to highly crystalline perovskite films. As a result of lower defects, PSCs obtained by PCl WBG CsPbIBr₂ achieved a PCE of 10.83%, possessing a <i>V</i> _oc of 1.24 and an enhanced stability of more than 300 h. This work may deliver a viable solution toward the fabrication of WBG CsPbIBr₂ PSCs sub-cells for tandem solar cells.