Synthesis and upconversion luminescence properties of Ho3+-Yb3+ co-doped glass ceramics containing LiGd(WO4)2

Ho3+-Yb3+ co-doped glass ceramics containing LiGd(WO4)2 were prepared by melt crystallization method. By using the methods of differential scanning calorimetry (DSC), X-ray diffraction (XRD), transmittance, and scanning electron microscopy (SEM), the optimal heat treatment condition for the samples was identified to be 580 °C/140 min. In these conditions, the transmittance of glass ceramic is about 75% in the 380-780 nm range. In the upconversion emission spectra, strong green emission (543 nm) and red emission (650 nm) due to 5F4/5S2, 5F5→5I8 transitions are observed at 980 nm excitation. Additionally, the optimum doping concentrations of Ho3+ and Yb3+ were 0.12% and 0.4%. The crystal field changes around dopant ions were analyzed using J-O theory and Eu3+ probe to explain the up-conversion luminescence enhancement of glass ceramics containing LiGd(WO4)2. The chrominance coordinates of 0.12% Ho3+-0.4% Yb3+ co-doped glass ceramics are located in the green light region, and the color purity is 95.6%. In summary, Ho3+-Yb3+ co-doped transparent glass ceramics containing LiGd(WO4)2 have potential applications in infrared detection and green solid-state lasers.