Dynamic Phosphorescence/Fluorescence Switching in Hybrid Metal Halides Toward Time‐Resolved Multi‐Level Anti‐Counterfeiting

Hybrid metal halides (HMHs) with time‐resolved luminescence behavior promise to be a breakthrough in multi‐level anti‐counterfeiting, but controlling the dynamic switching between phosphorescence and fluorescence is extremely challenging. Herein, an array of 0D HMHs is constructed by screening the π‐conjugated ligand with room‐temperature phosphorescence (RTP). Compared to the organic chromophore, (ETPP)2ZrCl6 possesses a misaligned stacking and rigid structure, contributing to an improved phosphorescence quantum yield (ΦP = 27.50%) and an extended phosphorescence lifetime (τ = 0.6234 s), as the intervening of inorganic unit [ZrCl6]2− suppresses the energy losses caused by nonradiative relaxation and prompts the intersystem crossover (ISC) process. Not only that, the interplay of phosphorescence‐fluorescence dual‐mode emission can be intelligently controlled by doping the active metal Te4+, resulting in a dynamic switching between RTP phosphorescence and self‐trapped exciton (STE) fluorescence. DFT calculations reveal the governing origins of RTP‐STE from the intermolecular ISC channels and spin‐orbit coupling (SOC) coefficients. These precise images into periodic pixelated arrays enable the multi‐level anti‐counterfeiting and information encryption. This work proposes a fluorescence‐phosphorescence co‐modulating strategy under the premise of dissecting the structural origins for optimizing RTP phosphorescence, which paves the way for designing high‐security‐level anti‐counterfeiting materials. (ETPP)2ZrCl6 possesses a misaligned stacking and rigid structure due to the intervention of [ZrCl6]2−, thus contributing to an improved phosphorescence quantum yield (ΦP = 27.50 %) and an extended phosphorescence lifetime (τ = 0.6234 s). Beyond that, the dual‐mode emissions are intelligently controlled by doping the active Te4+ with 5s2 lone‐pair electron, resulting in the dynamic switching between RTP phosphorescence and STE fluorescence.