Nd3+-sensitized upconversion white light emission of Tm3+/Ho3+ bridged by Yb3+ in β-YF3 nanocrystals embedded transparent glass ceramics

Red (Ho3+:F-5(5)-> I-5(8)), green (Ho3+:S-5(2), F-5(4)-> I-5(8)), and blue (Tm3+:D-1(2)-> F-3(4) and (1)G(4)-> H-3(6)) upconversion emissions were simultaneously generated in the transparent glass ceramics containing Nd3+/Yb3+/Tm3+/Ho3+:beta-YF3 nanocrystals under 796 nm excitation. It was experimentally evidenced that Yb3+ ions acted as the bridging centers to prompt energy transfer from Nd3+ to Tm3+ and Ho3+. With appropriately optimizing the contents and relative ratios of the doped rare earth species, luminescence of various colors, including bright white light, was easily tuned in the glass ceramics. The related upconversion mechanisms were proposed. (C) 2010 American Institute of Physics. [doi:10.1063/1.3380832]