Atomic and Electronic Properties of Doped CsPbBr₃ Perovskite: An Ab Initio Study

Lead halide perovskites have emerged as promising materials for a broad range of applications, including optoelectronic devices and solar cells. Nevertheless, their practical utilization is constrained by the physical properties of their constituent atoms. To address these limitations, it is essential to tailor the atomic and electronic structures of lead halide perovskites to meet specific functional requirements. Doping is explored in this work as a strategy to tailor the electronic structure of CsPbBr₃ perovskites. Various elements are considered as dopants at different crystallographic sites. The stability of doped CsPbBr₃ (generic form ABX₃) correlates primarily with the ionic radius of dopants at the A-site, and with both ionic radius and electronegativity at the B- and X-sites. Among the different doping sites, B-site substitution leads to the most pronounced changes in the electronic structure. The emergence of defect states and the variation in band gap are attributed to electronic effects from the atomic energy levels of dopants and geometric effects from their ionic radii. Defect states become less prominent at lower doping concentrations. Overall, electronic effects are found to play a more dominant role than geometric effects in shaping the band structure. Additionally, externally applied strain can further modulate the band gap of doped CsPbBr₃. This study provides insight into rational dopant selection for tuning the electronic properties of CsPbBr₃ for targeted applications. Potential applications include solar cells, light-emitting devices, lasers, and photodetectors, where doping enhances entropic stability, broadens absorption, and increases quantum yield.