Dual-enhancement of photoluminescence and cathodoluminescence in Eu3+-activated SrMoO4 phosphors by Na+ doping
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 Sr0.86MoO4:0.07Eu3+/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 Sr0.86MoO4:0.07Eu3+/0.07Na+ phosphor.