Rare-earth doped YF3 nanocrystals embedded in sol-gel silica glass matrix for white light generation

YF3 nanocrystals triply-doped with Yb3+, Ho3+ and Tm3+ ions embedded in amorphous silica matrix have been successfully obtained by heat treatment of precursor sol-gel glasses for the first time to our knowledge and confirmed by X-ray diffraction and luminescence measurements. Simultaneous UV and visible efficient up-conversion emissions, with well-resolved Stark structure, under 980 nm infrared pump are observed, indicating the effective partition of rare-earth ions into a crystalline-like environment of the YF3 nanocrystals. Corresponding energy transfer mechanisms have been analyzed and overall colour emission has been quantified in terms of standard chromaticity diagram. By an adequate doping level and heat treatment temperature of precursor sol-gel glasses, a bright white colour has been accomplished, close to the standard equal energy white light illumination point, with potential applications in photo-electronic devices and information processing.