Structural and luminescence properties of Dy3+ activated niobiosilicate glass with high thermal stability for W-LED application

A series of Dy3+ doped niobiosilicate luminescent glasses have been prepared by high temperature melting using the chemical composition of 35SiO2–35Nb2O5–10Na2O–20K2O-xDy2O3 (x = 0.2, 0.4, 0.6, 0.8, 1.0 and 1.2 mol%). Results of differential scanning calorimetry (DCS) show that the glass matrix has good thermal stability. Presence of [SiO4] and [NbO6] structural units in the glass was confirmed by FTIR and Raman spectral analyses. Results of UV–Vis–NIR absorption spectra show that Dy3+ doped optical glass can be excited by ultraviolet light, and the transmittance curve displays the high transmittance of the glass. Photoluminescence (PL) analysis reveals that there are three emission peaks: 4F9/2 → 6H15/2 (blue light), 4F9/2 → 6H13/2 (yellow light), and 4F9/2 → 6H11/2 (red light); the highest intensity of the samples is obtained at x = 0.8 mol%, and the variable temperature emission spectrum shows that the emission intensity at 423 K remains above 78.85 % that of room temperature. The CIE chrominance coordinate diagram determines that the chrominance coordinate value is close to the standard white light, the correlation color temperature calculation proves that it is located in the cold white light region. The decay curve can be fitted with the double exponential attenuation equation. The above results show that Dy3+ doped niobiosilicate glass has the potential to be used as W-LED material.