Synthesis and photoluminescence of novel red-emitting ZnWO4: Pr3 +, Li+ phosphors

• Successfully synthesized ZnWO4: Pr3 + and ZnWO4: Pr3 +, Li+ phosphors via solid state reaction method.
• Red emission of Pr3 + firstly increases and then decreases with increasing Pr3 +, Li+ contents.
• Luminescence decay time of 5.4 μs is obtained.
• The CIE chromaticity coordinates are obtained and exhibited red emission.

Zn0.997WO4: Pr3 +0.003 and different concentrations (0.1 mol% to 0.9 mol%) of Pr, Li co-doped ZnWO4 red phosphors were prepared by means of solid-state reaction process. The crystalline, surface morphology and luminescent properties of Zn0.997WO4: Pr3 +0.003 and Zn1 − x − yWO4: xPr3 +, yLi+ phosphors were investigated by the X-ray diffraction patterns (XRD), scanning electron microscope (SEM) and fluorescent measurements. From powder XRD analysis, the formation of monoclinic structure with C2/h point-group symmetry and P2/c space group of the as-synthesized samples is confirmed. The SEM image showed that surface morphology of the phosphor powder is irregular cylindricality. The luminescent spectra are dominated by the red emission peaks at 607, 621 and 643 nm, respectively, radiated from the 1D2 → 3H4, 3P0 → 3H6 and 3P0 → 3F2 transitions of Pr3 + ions. The concentrations of the highest luminescent intensity is determined at 0.3 mol% Pr3 + and 0.3 mol% Li co-doped ZnWO4 powder crystal, and the peak intensity is improved more than 3 times in comparison with that of 0.3 mol% Pr3 + single-doped ZnWO4. The enhanced luminescence comes from the improved crystalline and from the charge compensation of Li+ ions. The decay curve and CIE chromaticity coordinates of as-prepared samples are also studied in detail.

Figure. Photoluminescence excitation (PLE) and photoluminescence (PL) spectra of Zn0.997WO4: Pr3 +0.003 and Zn1-x-yWO4: Pr3 +x, Li+y phosphors.Figure optionsDownload as PowerPoint slide