Enhancement of Fluorescence from BaMoO4:Pr3+ Deep-Red-Emitting Phosphor via Codoping Li+ and Na+ Ions

Novel Li+- and Na+-doped BaMoO4:Pr3+ deep-red-emitting phosphors were synthesized using a solid-state reaction. The effects of codoping of Li+ and Na+ ions on the structure, morphology, and luminescent properties of BaMoO4:Pr3+ were investigated by X-ray diffraction, scanning electron microscopy, UV-Vis diffuse reflectivity, and photoluminescence spectra. The phosphors retained the scheelite-type tetragonal structure, regardless of codoping Li+ or Na+. Under excitation of blue light, these phosphors showed a dominant deep-red emission that peaked at 643 nm corresponding to P-3(0)-> F-3(2) transition of Pr3+ ions. The luminescence of BaMoO4:Pr3+ was remarkably enhanced by the incorporation of superfluous Li+ or Na+, which results not only from the improvement of surface and size distribution of particles but also from the sensitization of oxygen vacancies. The luminescence intensities of BaMoO4:0.01Pr(3+), 0.05Li(+) and BaMoO4:0.01Pr(3+), 0.10Na(+) are about 1.9 and 1.7 times higher than that of the commercial phosphor CaS:Eu2+, respectively.