Defect‐Mediated Single‐Phase Multimodal Luminescence in CaWO 4 : Eu 3+ for Multidimensional Optical Anti‐Counterfeiting Encryption

ABSTRACT Achieving dynamic multimodal luminescent behavior in a single‐phase matrix is essential for high‐security anti‐counterfeiting and optical encryption, yet most such materials are limited to static, stimulus‐specific emissions and lack dynamically reconfigurable, multidimensional optical responses. Herein, we report a self‐activated scheelite‐structured CaWO 4 : Eu 3+ phosphor with four orthogonal dynamically switchable luminescent channels, exhibiting multidimensional optical responses modulated by excitation wavelength, time, temperature, and mechanical force. The 4D luminescence originates from the synergy of host‐dopant energy transfer, defect‐engineered carrier traps, and Eu 3+ activators: excitation wavelength‐dependent emission derives from WO 4 2− → Eu 3+ energy transfer, persistent luminescence (PersL) is enabled by defect traps for charge carrier storage and release, temperature‐modulated emission stems from distinct thermal quenching of the WO 4 2− matrix and Eu 3+ characteristic emission, and mechano‐luminescence (ML) is triggered by frictional force‐induced carrier de‐trapping and recombination. The underlying energy storage and transfer mechanisms are elucidated via combined experimental characterizations and first‐principles calculations. This robust single‐matrix platform enables a versatile strategy for next‐generation dynamic information encryption and advanced optical security.