Synergistic High‐Contrast Photochromism and Dynamic Luminescence in Defective ZnS Enabling Multilevel Information Storage and Display

ABSTRACT Photochromic luminescent materials have emerged as a pivotal approach for optical information storage. However, most reported photochromic systems rely on limited readout modes, low coloration contrast, and poorly understood defect‐property correlations. Here, a chlorine‐doped ZnS was developed through an anion‐doping strategy using a molten salt shielding synthesis, integrating reversible photochromism (76.6% color contrast), excitation‐dependent emission modulation (460–520 nm), persistent luminescence (PersL), and dynamic luminescence intensity modulation (96.8% intensity contrast). The distinct excitation energy thresholds, temporal duration, and de‐excitation pathways of these optical phenomena suggest their origins in different defect species. Furthermore, by regulating the excitation energy (energy threshold 3.60 eV), different defect centers can be selectively activated, enabling multi‐trap coupling and photochromism‐mediated modulation of both photoluminescence (PL) and PersL. Leveraging the high color contrast and synergistic modulation mechanism, we developed a multilevel optical information encryption technology and preliminarily established the structure‐property relationship between defects and optical responses. This work provides new perspectives for tailoring optical properties via defect engineering and advancing optical storage systems.