Impact of potassium doping on the optoelectronic properties over inorganic and hybrid bismuth bromide perovskite thin films (A3Bi2Br9, A = Cs+, MA)†

The development of affordable and sustainable semiconductor materials is vital for meeting future technological demands. Over the past few years, halide perovskites have proven to be potential semiconductor materials. So far, lead halide perovskites have demonstrated remarkable performance in various applications, including solar cells, LEDs, and photocatalytic reactions. However, water instability and toxicity are substantial concerns when considering Pb²⁺ based perovskites on a commercial scale. Nowadays, bismuth (Bi³⁺)-based perovskite materials are considered a promising alternative to Pb²⁺. This study explores the impact of doping on the optoelectronic properties of inorganic and hybrid bismuth bromide-based perovskites. In this work, a specific amount of KBr is incorporated into the perovskite material, and its effects are analyzed. We found that KBr incorporation induces structural distortion in the perovskite lattice, which affects the bandgap. Additionally, KBr increases the grain size and aids in passivating defect states in the material. As a result, the photocurrent response, and device performance of the KBr-incorporated Cs₃Bi₂Br₉ perovskite are improved.