Rigid Phase Formation and Sb3+ Doping of Tin (IV) Halide Hybrids toward Photoluminescence Enhancement and Tuning for Anti‐Counterfeiting and Information Encryption

Abstract Multi‐excitonic emitting materials in luminescent metal halides are emerging candidates for anti‐counterfeiting and information encryption applications. Herein, ATPP 2 SnCl 6 (ATPP=acetonyltriphenylphosphonium) phase was designed and synthesized by rationally choosing emissive organic reagent of ATPPCl and non‐toxic stable metal ions of Sn 4+ , and Sb 3+ was further doped into ATPP 2 SnCl 6 to tune the photoluminescence with external self‐trapped excitons emission. The derived non‐toxic ATPP 2 SnCl 6 shows multi‐excitonic luminescent centers verified by optical study and differential charge‐density from density functional theory calculations. Incorporation of Sb 3+ dopants and the increasing concentrations induce the efficient energy transfer therein, thus enhancing photoluminescence quantum yield from 5.1 % to 73.8 %. The multi‐excitonic emission inspires the creation of information encryption and decryption by leveraging the photoluminescence from ATPPCl to ATPP 2 SnCl 6 host and ATPP 2 SnCl 6 : Sb 3+ . This study facilitates the anti‐counterfeiting application by employing solution‐processable luminescent metal halides materials with excitation‐dependent PL properties.