Highly Tunable Emission by Halide Engineering in Lead-Free Perovskite-Derivative Nanocrystals: The CsSnX (X = Cl, Br, Br/I, I) System.

Nanocrystals of CsSnX (X = Cl, Br, BrI, and I) have been prepared by a simple, optimized, hot-injection method, reporting for the first time the synthesis of CsSnCl, CsSnBr, and mixed CsSn(IBr) nanocrystalline samples. They all show a cubic crystal structure with a linear scaling of lattice parameter by changing the halide size. The prepared nanocrystals have spherical shape with average size from 3 to 6 nm depending on the nature of the halide and span an emission range from 444 nm (CsSnCl) to 790 nm (CsSnI) with a further modulation provided by mixed Br/I systems.