Preparation and luminescent properties of Ho,Yb: Tb₃Ga₅O₁₂ nano-powder

With ammonium bicarbonate as the precipitating agent, using Tb₄O₇, Ga₂O₃, Ho₂O₃, Yb₂O₃ as raw materials(the stoichiometry of Tb₄O₇ and Ga₂O₃) is 3: 5 and doping Yb³⁺(8at.%)/Ho³⁺(0.5at.%、1at.%、1.5at.%、2.0at.% respectively), Ho,Yb: Tb₃Ga₅O₁₂(Ho,Yb: TGG) nano-powder was sintered at 1 200 ℃ for 10 h to obtain a pure phase. The samples were characterized by XRD, TG-DTA, Infrared Spectroscopy(IRS), Scanning Electron Microscopy(SEM) and upconversion emission spectroscopy. The experimental results show that the average grain size of the samples is 38.10 nm under the temperature of 1 200 ℃. When the samples with Yb³⁺(8at.%)/Ho³⁺(1.5at.%) concentrations were used, there was a clear upconversion luminescence in the wavelength rage of blue, green and red by 980 nm LD. The formation mechanism was discussed at the same time. Analyse indicates that Ho³⁺ transits from excited states ⁵S₂ and ⁵F₄ to ground state ⁵I₈, achieving the launch of green, and it transits from excited states ⁵F₅ and ⁵F₃ to ground state ⁵I₈, achieving the launch of red and blue respectively.