|
Lithium aluminate with three crystal forms in nature: α-LiAlO 2 , β-LiAlO 2 , γ-LiAlO 2 . Wherein the α-LiAlO the 2 for the low temperature stable phase, the β-LiAlO the 2 is a metastable phase, at a certain temperature, will be converted into a high temperature nature stable γ-LiAlO 2 , accompanied by the expansion of the lattice volume, single phase γ-LiAlO 2 Preparation increasingly become the object of attention. In this paper, γ-LiAlO 2 matrix synthesis of luminescent materials, research and improve their luminescent properties. Using the gel combustion prepared by γ-LiAlO 2 : the of Eu 3 red fluorescent material. The samples prepared as a single tetragonal structure of γ-LiAlO 2 was phase, with space group P41212, sample morphology tetragonal flake, the average particle diameter of about 1 μm, the maximum excitation of the phosphor 5D0 → 7F2 transition of Eu 3 ion corresponding to the maximum emission peak at 613nm, peak 254nm, is a broadband excitation. Eu 3 and the doping amount of ions to impact on the light emission intensity of the sample and the luminous intensity within a certain range to an increasing trend with increasing dopant concentration, the optimum content of 1.0 mol%. Li as the charge-compensating agent, so that the luminous intensity of the sample to be increased. The sample emission peak still located 613nm, Eu 3 : Li doping ratio of 1:2 increase in luminous intensity. Using a sol-gel method, and soluble salts thereof as the raw material was calcined at 700 ℃, the synthesized γ-LiAlO the 2 : the Eu 3 red phosphor material. F → f transition from a broadband peak Eu 3 sharp line excitation spectrum of the spectral composition of the former is strong, the main peak at 254nm, is a UV excitation, sample the maximum emission peak at 613 nm, corresponding to 5D0 → 7F2 transition Eu 3 mainly in deviation or inversion symmetry Sites of. Meanwhile, the effects of γ-LiAlO 2 : EU 3 of the light emission intensity changes with flux H3BO3 doping concentration With B 3 concentration increases, the material emission intensity first increases and then decreases, optimal doping concentration 0.8mol% this time sample crystallinity. Citric acid sol-gel synthesis of γ-LiAlO 2 : Tb 3 green fluorescent material. Samples under UV excitation wavelength of 238nm, 450-650nm range appeared five characteristic emission peaks, the main peak of 542 nm, corresponding to the Tb 3 ions 5D4 → 7F5 transition. Tb 3 and the doping amount of ions to impact on the light emission intensity of the sample and the luminous intensity within a certain range to an increasing trend with increasing dopant concentration, the optimum content of 1.2 mol%. Li as charge compensation, the luminous intensity of the sample weakening trend in the first enhanced optimum doping ratio of the Tb 3 with Li 1.2:1. The emission peak of the sample is still located 542nm. Meanwhile, the effects of γ-LiAlO 2 : the Tb 3 of the luminous intensity, changes with flux H3BO3 doping concentration With B 3 concentration increases, the material emission intensity first increases and then decreases optimum doping concentration of 1.5 mol%, the best this time sample crystallinity.
|