Halide exchange mediated cation exchange facilitates room temperature co-doping of d-and f-block elements in cesium lead halide perovskite nanoparticles

This study presents a halide exchange mediated cation exchange reaction to co-dope d- and f-block elements in CsPbX₃ NPs at room temperature. Addition of MnCl₂ and YbCl₃ to CsPbBr₃ NPs induces ion exchange reactions generating the corresponding CsPbBr₃/MnCl₂YbCl₃ NPs. In addition to the perovskite emission, the NPs display sensitized Mn²⁺ and Yb³⁺ emissions in concert spanning the UV, visible, and NIR spectral region. Structural and spectroscopic characterizations indicate a substitutional displacement of Pb²⁺ by the Mn²⁺ and Yb³⁺. The identity of the host halide in modulating the ion exchange reactions was also tested. An effective perovskite host NP is presented that can be used to incorporate d-f or f-f dopant combinations to realize a gamut of dopant emission lines. A charge trapping based photophysical model is developed that focuses on rational energy alignments to predict dopant emissions semi-empirically and aids the design of optimal perovskite host-multi-dopant combinations.