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