Unveiling the mechanism of rare earth doping to optimize the optical performance of the CsPbBr3 perovskite

Abstract

Rare-earth (RE) doping is one of the valid approaches to optimize the optical performance of the CsPbBr₃ perovskite. However, the underlying mechanism and the role of the RE_4f electrons are still unknown, which are significant for the development of advanced RE-doped perovskite materials. Considering these, a series of CsPbBr₃:RE (RE = Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb) compounds were studied by applying first-principles calculations. Based on the analysis of the phase stability diagram, we found that RE doping in the bulk CsPbBr₃ leads to the formation of the RE_Pb defect. Meanwhile, the two types of electric-dipole allowed transition were revealed by exploring the electronic structure. We also demonstrated that the doped systems retain the defect tolerance nature of the host and the RE_4f electrons enrich the band-edge states, which are the main origins for luminescence enhancement. Our current contribution not only presents physical insight into the role of RE_4f electrons in luminescence, but also provides a guideline for designing the targeted RE-doped perovskites.