Structural Modifications due to Bi-Doping in MAPbBr₃ Single Crystals and Their Impact on Electronic Transport and Stability

Doping strategy in lead halide perovskites is essential to enhance its optoelectrical properties and expand the potential applications. In this work, the mechanisms, for how dopants affect the overall structural, optical, electrical, and chemical properties and stability of lead halide perovskite materials, are investigated. This is done by specifically considering various bismuth (Bi) doping concentrations in MAPbBr₃ single crystals grown using the inverse temperature crystallization method. The resultant doped single crystals exhibit a saturation point when Bi concentration exceeds 0.063% which is considered an optimum doping point. The highest thermal stability is also achieved at this doping concentration among the doped single crystals. This study clearly identifies how Bi doping affects the properties of MAPbBr₃ and extends to consider stability, which has not been fully considered for MA-based perovskites previously. This will provide a clear understanding of evaluating doped perovskite materials for enhanced material properties, device performance, and stability.