Modulating trap properties by Nd³⁺- Eu³⁺ co-doping in Sr₂SnO₄ host for optical information storage

We report a novel Nd³⁺ and Eu³⁺ co-doped Sr₂SnO₄ (SSONE) phosphor showing the capability of "write-in" and "read-out" in optical information storage. As-prepared phosphors exhibit a dominant emission (PL) band centered at 596 nm under UV excitation, closely identical with its photo-stimulated luminescence (PSL) spectrum center (595 nm) upon near-infrared (NIR) light and thermal-stimulated luminescence (TSL) spectrum center (595 nm) under heat source. Remarkably, compared with Eu³⁺ single-doped phosphors, the co-doping strategy enhances the deep traps and also separates the deep traps with shallow traps, which are very crucial factors for optical information storage in electron trapping materials. Further, a demonstration confirmed the optical information storage capacity by photo- and thermal-stimulating the prepared phosphors filled in the designed patterns.