Fabrication and Luminescence Properties of Ca2Gd8 (SiO4)6O2: Er3+ Phosphors via Sol-Gel Process

Ca 2 RE 8 (SiO 4 ) 6 O 2 (RE = Y, Gd, La) is a kind of ternary rare-earth-metal silicate with the oxyapatite structure, which was used as host materials for the luminescence of various rare earth and mercury-like ions. Ca 2 Gd 8 (SiO 4 ) 6 O 2 :Er 3+ phosphors were prepared through the sol-gel process. X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence spectra were used to characterize the resulting phosphors. The results of XRD indicate that the phosphors crystallized completely at 1000 °C. SEM study reveals that the average grain size is 400 ∼ 1000 nm. In Ca 2 Gd 8 (SiO 4 ) 6 O 2 : Er 3+ shows its characteristic green emission at 528 nm ( 2 H 11/2 - 4 I 15/2 ) and 548 nm ( 4 S 3/2 - 4 I 15/2 ) upon excitation into 382 nm, with an optimum doping concentration of 5% (mole fraction) of Gd 3+ in the host lattices.