Development of a cyan blue-emitting Ba3La2(BO3)(4):Ce3+,Tb3+ phosphor for use in dental glazing materials: color tunable emission and energy transfer

Abstract

The Ce3+/Tb3+ doped Ba3La2(BO3)(4) phosphors were synthesized by a conventional solid state reaction method. The synthesized phosphor samples are a single phase of Ba3La2(BO3)(4) and showed angular-shaped fine grains with average particle size from 5 mu m to 10 mu m. The Ba3La2(BO3)(4):Ce3+ phosphors showed an asymmetric broad blue emission under excitation at 365 nm and the Ba3La2(BO3)(4):Tb3+ phosphors exhibited typical green emission assigned to the 4f-4f transition of Tb3+ under excitation at 254 nm. Under near-UV (365 nm) excitation, Ba3La2(BO3)(4):Ce3+,Tb3+ phosphors showed both a blue emission band and green emission peaks due to Ce3+ and Tb3+, respectively. By optimizing the composition, cyan-blue emission with high color purity (CIE chromaticity coordinate values x = 0.2557 and y = 0.3839) was obtained for the Ba3La2(BO3)(4):0.05Ce(3+),0.03Tb(3+) phosphor, and the internal quantum efficiency of the phosphor at the excitation wavelength of 365 nm is estimated to be 50%. The dental glazing paste prepared by mixing organic binder, Ba3La2(BO3)(4):Ce3+,Tb3+ phosphors, and low T-g glass was successfully vitrified when it was heated at 600 and 700 degrees C, and showed high chemical stability of the luminescence properties in acidic aqueous solution (pH = 4).