Concentration and annealing effect on PL properties of sol-gel derived SiO2-Y2O3:Eu3+ nanocomposites

An improved sol-gel method was employed to prepare Eu3+ ions doped SiO2-Y2O3 nanocomposites. Systematic study was carried out on the effect of post-annealing treatment on photoluminescence (PL) properties of the samples under various europium ions doping concentrations. X-ray diffraction (XRD) patterns indicated that the samples showed an amorphous matrix structure, and the scanning electron microscopy (SEM) pictures showed that the samples presented a nano size (from 21 to 42 nm) granular-stack structure after high-temperature annealing treatment (from 600 to 900 °C, respectively) for 3 h. Raman spectra demonstrated that Y3+ and Eu3+ ions were incorporated into the composites through the sol-gel and post-annealing process. Under the excitation of 394 nm (7F0→5L6) light, red emission was observed around 613 nm (5D0→7F2). Without annealing treatment, the optimized doping amount of Eu ions was about 6.5 mol.%, which was much higher than that single doped in SiO2 glass matrix with Eu ions concentration of 3%, and it raised to 9.0% when the samples were annealed at high-temperature (900 °C) annealing.