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

Multi-excitonic emitting materials in luminescent metal halides are emerging candidates for anti-counterfeiting and information encryption applications. Herein, ATPP₂SnCl₆ (ATPP=acetonyltriphenylphosphonium) phase was designed and synthesized by rationally choosing emissive organic reagent of ATPPCl and non-toxic stable metal ions of Sn⁴⁺, and Sb³⁺ was further doped into ATPP₂SnCl₆ to tune the photoluminescence with external self-trapped excitons emission. The derived non-toxic ATPP₂SnCl₆ shows multi-excitonic luminescent centers verified by optical study and differential charge-density from density functional theory calculations. Incorporation of Sb³⁺ 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 ATPP₂SnCl₆ host and ATPP₂SnCl₆ : Sb³⁺. This study facilitates the anti-counterfeiting application by employing solution-processable luminescent metal halides materials with excitation-dependent PL properties.