Photoluminescence properties and energy transfer mechanism of Eu3+-Tb3+-Pr3+ triple-doped Gd2O3 phosphors

Abstract

In this paper, Eu³⁺-Tb³⁺-Pr³⁺ triple-doped Gd₂O₃ phosphors based on solar-blind ultraviolet band response were successfully prepared by the hydrothermal method. All the phosphor samples exhibit excellent crystallinity and the crystal structures are cubic crystal phases. The doping of Tb³⁺ and Pr³⁺ significantly enhance the luminescence intensity of Gd₂O₃:Eu³⁺. This is attributed that ⁵D₄ energy level of Tb³⁺ and ³P₀ energy level of Pr³⁺ can transfer energy to ⁵D₁ energy level of Eu³⁺. The phosphor is effectively excited at 265 nm with the optimal luminescence intensity when the doping concentrations of Eu³⁺, Tb³⁺, and Pr³⁺ are 4 mol%, 0.075 mol%, and 0.03 mol%, respectively. Fluorescence lifetime tests show that Tb³⁺ and Pr³⁺ as sensitizers could effectively enhance the red light emission of Eu³⁺ through quadrupole-quadrupole and dipole-dipole interactions, respectively. In addition, the doping of Tb³⁺ and Pr³⁺ can further improve the thermal stability of Gd₂O₃:Eu³⁺. And the emission intensity of Eu³⁺-Tb³⁺-Pr³⁺ triple-doped Gd₂O₃ phosphors at 428 K is 61.94 % of that at room temperature, which is much larger than that of 41.32 % for Gd₂O₃:Eu³⁺. Therefore, Gd₂O₃:Eu³⁺, Tb³⁺, Pr³⁺ phosphors exhibit potential applications in solar-blind ultraviolet band detection field, meriting further research and exploration.