Luminescence of complex ion WO1218− in Dy3+ doped nanocrystal Gd6WO12 phosphor

Nanocrystal Gd6WO12 phosphor doped with Dy3+ was prepared by a co-precipitation method. X-ray diffraction (XRD), scanning electron microscopy (SEM) and selected area electron diffraction (SAED) were used to characterize the structure and morphology of the resultant phosphor. It was found that the phosphor exists in tetragonal phase and the phosphor particles show sphere-like shape with an average size of 31 nm. In aid of excitation and emission spectra, the energy levels of the complex ion WO1218− were confirmed, and that the possible luminescent mechanisms for various wavelengths excitation were analyzed. The cross relaxation and energy transfer between complex ion and Dy3+ were discussed. The dependence of luminescent intensity and color coordinates on the excitation wavelength was also investigated.

Research highlights▶ Novel nanosized Gd6WO12 phosphor was synthesized via a co-precipitation technique. ▶ Energy level structure of complex ion WO1218− was confirmed. ▶ Energy transfers 1T2 + 1A1 → 3T1 + 3T2, 1T1 + 6H15/2 → 3T2 + 6F1/2 and 4F9/2(4I15/2, 4G11/2) + 1A1 → 3T1(3T2) + 6H15/2 were observed. ▶ Dependence of luminescence intensity and color coordinates on the excitation wavelength was studied.