Novel Sr2LuF7–SiO2 nano-glass-ceramics: Structure and up-conversion luminescence
Novel transparent nano-glass-ceramics comprising RE-doped Sr2LuF7 nanocrystals have been obtained by thermal treatment of precursor sol–gel glasses. The precipitated Sr2LuF7 nanocrystals with sizes from 4.5 to 11.5 nm, confirmed by X-Ray Diffraction and Transmission Electron Microscopy images, show a cubic phase structure. The luminescent features of Eu3+ ions, used as structural probes, evidence the distribution of RE ions into the fluoride nanocrystals. Under 980 nm laser excitation, intense UV, vis and NIR up-conversion emissions were observed and studied in Yb3+–Tm3+, Yb3+–Er3+ and Yb3+–Ho3+ co-doped nano-glass-ceramics. These results suggest considering these nano-glass-ceramics for potential optical applications as high efficient UV up-conversion materials in UV solid state lasers, infrared tuneable phosphors and photonic integrated devices.