Color tunability and white light generation through up-conversion energy transfer in Yb3+ sensitized Ho3+/Tm3+ doped tellurite glasses

In this study, tellurite glasses in the (50-x)TeO2-25WO(3)-25Li(2)O-xRE (RE: Ho3+, Tm3+, Yb3+) system were synthesized to investigate white light generation through up-conversion energy transfer. Thermal properties of glasses were studied, and optical absorption spectra were collected. Energy transfer mechanisms between RE ions and effect of RE concentrations on up-conversion emission and color tunability were investigated through photoluminescence analysis under 980 nm excitation. Additionally, effect of excitation power on up-conversion emission intensities were investigated. Colorimetric properties such as CIE color coordinates, correlated color temperature, color rendering index and color purity were calculated. The obtained colorimetric results under 2 watt pump power were comparable or better than other reported glass systems. H005T025Y2 sample was found to show the closest color coordinates (x = 0.32 and y = 0.33) to pure white light and suitable colorimetric properties indicating that studied glasses have high potentiality to be used as luminescent materials for white light generation.