Dual-enhancement of photoluminescence and cathodoluminescence in Eu3+-activated SrMoO4 phosphors by Na+ doping

Abstract

Eu³⁺-activated and Eu³⁺/Na⁺-coactivated SrMoO₄ phosphors were prepared by a conventional high-temperature solid-state reaction method. The characteristic properties of the as-prepared phosphors were investigated by photoluminescence (PL) and cathodoluminescence (CL) spectra, together with PL decay curves, as well as X-ray diffraction (XRD) patterns. The XRD results confirmed that all the samples exhibited a pure tetragonal phase. Under 290 nm excitation, the PL emission intensity of the Eu³⁺-activated SrMoO₄ phosphors was increased by increasing the Eu³⁺ ion concentration, indicating an optimal concentration of 7 mol%. As a charge compensator, Na⁺ ions were incorporated into the SrMoO₄:7 mol% Eu³⁺ (i.e., 0.07Eu³⁺) phosphor and the PL emission intensity increased gradually with the increment of Na⁺ ion concentration, which reaches its maximum value at 7 mol%. Furthermore, the color purity of the Sr_0.86MoO₄:0.07Eu³⁺/0.07Na⁺ phosphor was as high as 92.1% and its Commission Internationale de I'Eclairage chromaticity coordinate was very close to that of standard red light. Ultimately, under low-voltage electron beam excitation, strong CL properties were observed in the Sr_0.86MoO₄:0.07Eu³⁺/0.07Na⁺ phosphor.