ns ² Ion‐Dual‐Doping Modulated Competitive Carrier Capture in Room‐Temperature Phosphors for Multi‐Level Anti‐Counterfeiting

ABSTRACT

With rising information security demands, multidimensional anti‐counterfeiting materials have spurred research. However, singly doped matrices suffer from limited spectral and temporal complexity, posing cloning and decryption risks. In this study, we reveal that co‐doping ns ² metal ions (Bi ³⁺ and Sb ³⁺ ) into the zero‐dimensional organometallic halide (Ph ₃ S) ₂ SnCl ₆ enables the emergence of switchable dual self‐trapped exciton (STE) emissions. By adjusting the concentration of Sb ³⁺ , the competitive carrier capture pathways from the S ₁ state to the Bi‐STE and Sb‐STE centers can be selectively regulated, leading to precise spectral tuning from blue to orange‐red. Furthermore, the material exhibits distinct thermochromic behavior. Based on its thermochromism and time‐/temperature‐dependent STE dynamics, a multi‐level anti‐counterfeiting system integrating multi‐level encoding has been constructed. This work demonstrates that the competitive carrier capture mechanism introduced by Bi ³⁺ /Sb ³⁺ co‐doping allows for independent multidimensional programming of color, lifetime, and thermal response, thereby establishing a unique optical fingerprint. It provides both a material platform and a mechanistic basis for the development of spectrally high‐security multi‐level luminescent encryption systems.