Design of efficient color-tunable long persistent luminescence phosphor BaGa2O4:Pr3+ and its performance enhancement via a trap-induced strategy

Abstract

Color-tunable long persistent luminescence (LPL) phosphors are more strongly desired for intelligent anti-counterfeiting and information storage compared with single color types. Herein, BaGa₂O₄ (BGO): x% Pr³⁺, y% Zn²⁺ (0.005 ≤ x ≤ 1.0, 0.5 ≤ y ≤ 3.0) are synthesized using a simple solid-state method and its crystal structure, optical performances, and trap properties are discussed in detail. The structure refinement implies Pr³⁺ and Zn²⁺ occupy Ba²⁺ and Ga³⁺ sites respectively, which lead to cell expansion along the c-axis and could be conducive to generating the defects such as oxygen vacancy , and . Spectrum analyzation shows that due to energy transfer from host luminescence to Pr³⁺ and its cross-relaxation, the PL shows color-tunable (blue to white even to red) emission. The addition of Zn²⁺ can enhance the host-defect luminescence range of 400–550 nm closely related to and the change in band gaps. Thus, the optimal LPL sample, BGO: 0.6% Pr³⁺, 2.0% Zn²⁺ (initial brightness: ∼0.256 cd m⁻², LPL decay time: ∼3500 s), is obtained. Moreover, based on DFT calculation, can be easily generated with the formation energy of 5.75 eV. In addition, the effect of is further studied by thermal-luminescence curve (TL), X-ray photoelectron spectroscopy (XPS) and electron spin resonance spectroscopy (ESR). According to the results, a possible LPL mechanism is proposed, and the dynamic multi-color pieces are designed for anti-counterfeiting.