Enhanced performance of BiI₃-incorporated CsPbBr₃ solar cells

CsPbBr₃ all-inorganic perovskite solar cells (PSCs) have been extensively investigated due to their remarkable stability. However, their limited film quality and wide bandgap result in a low photoelectric conversion efficiency (PCE). In this study, BiI₃ was incorporated into CsPbBr₃ films to synergistically enhance light absorption and film quality. It was found that the partial substitution of Pb²⁺ and Br^- with Bi³⁺ and I^- in CsPbBr₃ improved film quality, enhanced light absorption, and facilitated charge transfer and extraction. The device incorporating BiI₃-incorporated CsPbBr₃ as a light absorbing layer achieved an efficiency of 9.54%, exhibiting a significant enhancement of 19.4% compared to the undoped device. This work provides a new incorporating strategy that collaboratively improves light absorption and film quality.