Regulation of Intrinsic Defects of Self‐Activated MgGa2O4 Phosphors for Temperature Dynamic Anti‐Counterfeiting

Abstract Photoluminescent (PL) anti‐counterfeiting plays a critical role in encrypted information and anti‐counterfeiting. Dynamic PL anti‐counterfeiting technology provides advanced security features compared with static counterparts. Yet, many current dynamic luminescent materials rely solely on an optical storage mechanism, leading to a lack of diversification and making them vulnerable to replication. Here, dynamic PL emission triggered by ambient temperature variations is addressed. By modifying the sintering atmospheres and non‐stoichiometric ratio of MgGa 2 O 4 (MGO) samples, the concentration of intrinsic defects of the host are modified, resulting in temperature‐sensitive PL output dynamically manipulated from blue to green to red. Density‐functional theory (DFT) analysis elucidates the formation energies of intrinsic defects in the MGO samples, revealing that the self‐activated blue, green, and red emissions stem from lattice defects, [GaO 6 ], antisite defects , and interstitial oxygen (), respectively. Additionally, by monitoring the luminescence lifetime, and the thermoluminescence (TL) curves of the MGO samples, it is shown that the dynamic PL emission is generated by a combination of thermally assisted carrier migration and thermal compensation from trapping centers. Herein, a dual‐channel encrypted dot matrix is designed to enhance information transfer security through the interference between the dual channels, showcasing the practical application of this dynamic anti‐counterfeiting technique.