Up-conversion white emission and other luminescence properties of a YAG:Yb 2 O 3 ·Tm 2 O 3 ·Ho 2 O 3 @SiO 2 glass-nanocomposite.

We report on a glass-nanocomposite material consisting of yttrium aluminum garnet (Y 3 Al 5 O 12 , YAG) nanocrystals co-doped with Yb 3+ , Tm 3+ and Ho 3+ ions as well as entrapped into a SiO 2 xerogel. This 94YAG·5Yb 2 O 3 ·0.8Tm 2 O 3 ·0.2Ho 2 O 3 @SiO 2 (abbr. YAG:YbTmHo@SiO 2 ) nanocomposite material has been prepared by sol-gel procedure. Its structure and morphology has been characterized by means of X-ray diffraction (XRD) and scanning electron microscope (SEM) techniques as well as energy dispersive X-ray (EDX), X-ray photoelectron (XPS) and luminescence spectroscopies. The luminescent glass-nanocomposite exhibited an up-conversion effect under λ exc = 980 nm and emission when excited under 355 nm in steady-state conditions. Then time-resolved luminescence emission was observed, when the sample was excited at 290 and 355 nm by a pulse laser. Average decay times for the SiO 2 matrix and for some transitions of the Tm 3+ and Ho 3+ dopants present in the YAG:YbTmHo@SiO 2 material have been evaluated. The luminescent nanocomposite when excited under 290 or 355 nm wavelengths in both conditions emits blue light. However, the nanocomposite is promising as a single-source white-light phosphor owing to its up-conversion luminescence under 980 nm excitation. Such optical features make the studied material an alternative phosphor.