Room temperature doping of Ln3+ 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 (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.