Highly efficient and tunable white light emission of Sn2+-Dy3+ co-doped fluorophosphate glasses

A series of Sn2+-Dy3+ co-doped fluorophosphate glasses (FPGs) were prepared by the melt quenching method. The luminescent properties and energy transfer mechanisms of the FPGs glasses were investigated through photoluminescence and decay lifetime analysis. By controlling the concentration of Dy3+, the FPGs present a white light with a CIE chromaticity coordinate of (0.311, 0.330), which is very close to the standard equal energy white light illumination. The corresponding quantum efficiency, CRI and the brightness are 56.3%, 75 and 6706 cd/m2, respectively. Furthermore, the physical and chemical stability and thermal properties were also analyzed using differential scanning calorimetry and a thermal conductivity detector. The corresponding values of the ∆T (Tx-Tg) and thermal conductivity are 155 °C and 3.02~3.31 W/m·K, respectively. These results demonstrate that the FPGs can be a promising candidate for tunable white light phosphors.