Luminescence, energy transfer properties of Dy3+/Eu3+ coactivated neutral and warm white emissions GSBG glasses

Dy3+/Eu3+ co-doped GeO2-SiO2-BaO-Ga2O3(GSBG) glass was prepared by the traditional high temperature melting method. The structure and the optical performance of the sample were characterized through X-Ray Diffraction, absorption spectra, photoluminescence spectra, the fluorescence decay time and CIE chromaticity coordinates. The density of the samples was measured. The band gap and the distance between the rare earth ions were calculated theoretically. The energy transfer between Dy3+-Eu3+ was analyzed by Dexter energy transfer formula and I-H model. The results showed that the gap width of Dy3+/Eu3+ doped GSBG glass decreased from 4.6617 eV to 4.1472 eV and the decay time of fluorescence also decreases continuously with the increase of Eu3+ concentrations. The characteristic emission bands of Dy3+ at 483 nm and 574 nm are weakened, while those of Eu3+ at 590 nm and 614 nm are significantly enhanced, indicating that there is energy transfer between Dy3+-Eu3+ and the energy transfer is electric dipole-electric dipole transfer. It is worth noting that the prepared glass emits bright white light under ultraviolet excitation. In particular, sample DE0.5 emits neutral or warm white light under 365 nm excitation. The correlated color temperature is 4763 K; the color coordinate is x = 0.3487, y = 0.3271 and the color purity is low to 10.88%, close to the standard white light.