Luminescence properties and optical sensing behaviors of Sr2GdSbO6:Eu3+ phosphors

Abstract

Novel orange-red Sr₂GdSbO₆:xEu³⁺ (x = 0, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6) phosphors were successfully prepared by the traditional high-temperature solid-state method. The results of Rietveld refinement, energy dispersive spectroscopy (EDS) spectrum and elemental mapping demonstrate that Eu³⁺ successfully replaces the Gd³⁺ sites and distributes uniformly in the particles of phosphors. The luminescence properties of Sr₂GdSbO₆:Eu³⁺ phosphors were investigated in detail. The emission spectra of the strongest emission peak is the ⁵D₀→⁷F₁ (593 nm) transition, which can emit orange-red light under 393 nm excitation. When the doping concentration of Eu³⁺ ions is x = 0.2, the luminescence intensity of the phosphors reaches the highest. The detailed mechanism of concentration quenching is attributed to dipole-dipole interaction. The thermal stability values of Sr₂GdSbO₆:0.2Eu³⁺ phosphors are 87%, 82% and 114% under 393, 467 and 527 nm excitations, respectively. The causes of the abnormal thermal quenching under 527 nm excitation were analyzed. Based on the abnormal thermal quenching under 527 nm excitation, the optical thermometry properties of Sr₂GdSbO₆:0.2Eu³⁺ phosphors were investigated by fluorescence intensity ratio (FIR) technique, and appreciable relative sensitivity was obtained. The results suggest that Sr₂GdSbO₆:0.2Eu³⁺ phosphors can be potentially applied to w-LEDs and optical thermometers.