Room temperature doping of Ln3+ in perovskite nanoparticles: a halide exchange mediated cation exchange approach

Abstract

This study presents a halide exchange mediated cation exchange strategy for a room temperature doping of trivalent lanthanide cations (Ln³⁺) in cesium lead halide (CsPbX₃) nanoparticles (NPs). Post-synthetic addition of LnCl₃ [Ln = Nd, Sm, Eu, Tb, Dy, and Yb] to a solution of CsPbBr₃ NPs generates the corresponding lanthanide doped NPs which display host sensitized Ln³⁺ emission. Structural and spectroscopic characterizations indicate a successful halide exchange and substitutional displacement of Pb²⁺ by Ln³⁺. The effect of halide identity in controlling the Ln³⁺ sensitization was also evaluated. A photophysical framework is presented that can be used to predict the Ln³⁺ sensitization in perovskite NPs semiempirically, thereby removing the constraints of trial and error in designing a perovskite NP-Ln³⁺ host–guest combination.