Tuning Stability and Optoelectronic Properties of CsSnI₃ Via Rare-Earth Doping

This study focuses on tin (Sn)-based halide perovskite CsSnI₃, aiming to mitigate the environmental toxicity associated with lead-containing perovskites and to explore potential applications in optoelectronic devices. Considering the challenges of easy oxidation and poor thermodynamic stability in pristine Sn-based perovskites, rare-earth elements doping is proposed to regulate the structure and properties of CsSnI₃. The unique electronic orbital characteristics of rare-earth elements dopants can effectively influence atomic bonding, thereby significantly tuning the thermodynamic stability. Meanwhile, the local lattice distortion induced by rare-earth elements incorporation further redistributes the charge density around the dopant site, thereby suppressing oxidation and enhancing chemical stability. The theoretical calculations reveal that rare-earth elements doping can also significantly change the electronic properties through the involvement of d-orbital electrons. Moreover, optical analysis indicates that rare-earth elements doping mainly induces noticeable modulation of the dielectric function and enhances the optical response in the relatively low-energy region. This work provides a theoretical foundation and computational guidance for enhancing the stability and optoelectronic performance of Sn-based perovskites through precise doping strategies, offering new insights into the development of high-performance, lead-free, and environmentally friendly optoelectronic devices.