Transparent Yb3+-Er3+-Tm3+ co-doped nano-glass-ceramics have
been prepared, 32(SiO2) 9(AlO1.5) 31.5(CdF2) 18.5(PbF2)
5.5(ZnF2): 3.5(Yb-Er-TmF3) mol%, where the co-dopants partition
mostly to the fluoride PbF2-based nano-crystals. A comparative study of
the up-conversion luminescence in nano-glass-ceramics and its precursor
glass indicates that these materials can be used as blue/green/red tuneable up-conversion phosphor,
in particular for white light generation. A ratio between blue, green and
red emission bands of the Tm3+ and Er3+ can be widely varied with
nano-ceramming of the precursor glass and with changing a pump power of
luminescence. The change in the ratio between the blue, green and red
emission bands is explained to be due to substantial lowering phonon energy
and shortening of inter-dopant distances with nano-ceramming of the
precursor glass and due to change in the ratio of 2- and 3-photon
up-conversion processes with pump power.