Fabrication and luminescence of highly transparent C12A7:Tb3+ glass-ceramics via in-situ crystallization from aerodynamic levitation processed glasses

Rare earth doped 12CaO·7Al2O3 (C12A7) glass-ceramics are one of attractive photonic materials due to their high transparency, high luminescent efficiency and eco-friendly nature. A series of C12A7 glasses with different Tb3+ doping concentrations was prepared by aerodynamic levitation method. The C12A7:Tb glass-ceramics were obtained via in-situ growth from the glasses with the identical chemical composition at 800 °C. The microstructure observation demonstrates that the elemental distributions of Ca and Al are homogeneous in the glass-ceramics and the grain size of C12A7 is 4–70 nm. The in-line transmittance of glass-ceramics reaches as high as 82% at 1500 nm. The emission spectra of the C12A7:Tb glass-ceramics present characteristic Tb3+ emission peaks at 486 nm (5D4→7F6), 541 nm (5D4→7F5), 585 nm (5D4→7F4) and 621 nm (5D4→7F3). The photoluminescence lifetime of C12A7:0.3%Tb glass-ceramic is 1.9 ms. Compared with the emission intensity of the glasses, that of the glass-ceramics increases due to the reducing in concentration of oxygen vacancy associated with network forming (NWF) cations. The highly transparent C12A7:Tb glass-ceramics may be a promising candidate for green light source in solid state lighting.