Structure, luminescence and temperature sensing in rare earth doped glass ceramics containing NaY(WO4)2 nanocrystals

Novel rare earth doped glass ceramics containing NaY(WO4)(2) nanocrystals were fabricated for the first time. The appearance of sharp diffraction peaks and well-resolved lattice fringes certifies the precipitation of NaY(WO4)(2) nanocrystals with high crystallinity. After the crystallization process, significant changes in the photoluminescence emission spectra and fluorescence lifetime of Sm3+ ions are observed, which are ascribable to the enrichment of Sm3+ ions in the highly disordered NaY(WO4)(2) nanocrystals. Under 980 nm excitation, characteristic green and red upconversion emission signals were detected and the enhanced upconversion luminescence of Er3+ ions in the glass ceramics was attributable to the incorporation into the low energy phonon NaY(WO4)(2) nanocrystals. Based on the dependence of upconversion intensity on the excitation power, the upconversion mechanism of Er3+-Yb3+ ions was proposed. The temperature-dependent fluorescence intensity ratio (FIR) of the thermally-coupled H-2(11/2) and S-4(3/2) energy levels was determined at a low power density of 0.4125 W cm(-2). The maximum temperature sensitivity is 146 x 10(-4) K-1 at 523 K, which is mainly attributed to the highly disordered structure of NaY(WO4)(2) nanocrystals and exhibits promising potential for optical temperature sensors.