Room temperature doping of Ln in perovskite nanoparticles: a halide exchange mediated cation exchange approach.

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