Self‐Activated Luminescence Facilitating Stimuli‐Responsive Colorimetric Modulation in Quaternary Piezo‐Photonic Phosphors

ABSTRACT Multimodal luminescent materials are typically characterized by the necessity of doping or co‐doping with multiple rare‐earth or transition metal ions, which introduces complex tunneling effects and energy transfer mechanisms. This complexity can result in uncontrollable defect structures, varying kinetic processes, or significant luminescence quenching, thereby constraining their practical applications. To address these limitations, a microwave‐irradiation induced defect‐engineered strategy is proposed, aimed at facilitating the integration of both self‐activated and multi‐stimulus‐responsive luminescence. Quaternary piezo‐photonic CaZnOS:Sm 3+ phosphors were synthesized via the microwave‐assisted solid‐state technique, and their multimodal luminescence and trap distribution characteristics were systematically characterized. It has been further revealed that the self‐activated luminescent CaZnOS matrix is characterized by the presence of both shallow and deep traps (up to 1.40 eV), which facilitates the generation of green emission. Additionally, the incorporation of Sm 3+ ions provides a distinctive orange–yellow 4 f ‐4 f transition, thereby enabling excitation‐dependent color modulation and promoting flexible multi‐responsive luminescence. This study employs a microwave‐irradiation‐induced defect‐engineered approach to facilitate self‐activated luminescence, thereby enabling color tunable light emission that is responsive to variations in wavelength, temperature, and mechanical stress. This innovative system holds considerable potential for dynamic anti‐counterfeiting displays, and multimodal sensing applications encompassing optical, thermal, and mechanical modalities.