Non‐Equivalent Substitution‐Engineered Bistable Traps in Mg ₂ GeO ₄ :Bi ³⁺ ,Ln ³⁺ Persistent Phosphors for Non‐Volatile Information Storage

Abstract Persistent luminescence (PersL) materials hold immense potential for information storage and anti‐counterfeiting applications. However, realizing non‐volatile optical memory remains challenging. Herein, we design Mg ₂ GeO ₄ :Bi ³⁺ ,Ln ³⁺ (Ln = Tb, Eu) PersL phosphors via non‐equivalent substitution engineering, where Bi ³⁺ and Ln ³⁺ ions deliberately occupy non‐equivalent Mg1/Mg2 sites to create bistable deep traps. This strategy generates an ultra‐broadband, high‐density trap distribution, enabling strong photo/thermo‐stimulated luminescence for recalling excitation‐field temperatures. The trapped carriers exhibit temperature‐dependent storage and release dynamics, allowing reconstruction of excitation thermal histories. Based on this unique behavior, reconfigurable optical memory anti‐counterfeiting patterns in phosphor films are demonstrated. The trapping mechanism, validated by thermoluminescence and XPS spectra, reveals that carrier redistribution follows Fermi‐Dirac statistics governed by the interaction between trap levels and thermal lattice waves. This work opens new avenues for non‐volatile optical data storage with high security and spatiotemporal resolution.