Investigation On The Preparation And Fluorescent Properties Of Rare Earth Ions Doping GdAlO₃ Phosphor

The precursor of rare earth inos RE³⁺?RE=Dy,Tb,Eu?doping gadolinium aluminum perovskite solid solutions were obtained through co-precipitation technology?rare earth nitrate as the mother salt,ammonium bicarbonate as precipitant?,followed by calcining at 800-1300 oC.The effect of rare earth inos concentration,precursor calcination temperature and the kinds of flux on the material's microstructure,the partical size and fluorescence properties of GdAlO₃:RE³⁺ phosphors were discussed in detail.Utilizing the energy transfer effect from the Gd³⁺ inos in the host lattice,the strategy effectively improved the photoluminescence intensity of rare earth inos.The mainly conclusions as following:?1?The loosely agglomerated precursor of(Gd_1-xTb_x)AlO₃?x=0-0.12?phosphors were synthesized via ammonium bicarbonate co-precipitation technology,then calcined at high temperature to obtain a series of green phosphors.The pure phase(Gd_1-xTb_x)AlO₃ can be achieved by annealing at 1000 ?,the uniform morphology and good dispersion of phosphor can be kept.Under the optimized UV excitation wavelength of 275 nm(4f⁸-4f75d1 transition of Tb³⁺),which completely overlaps the 8S7/2-6I2/3 transition of Gd³⁺,the photoluminescence?PL?spectra displayed excellent green emission at ⁵46 nm(5D4-7F5 transition of Tb³⁺).The results mentioned above suggested that the process of energy transfer appeared between Gd³⁺ and Tb³⁺.The quenching concentration of Tb³⁺ was determined to be ¹0 at% in GdAlO₃ solid solutions,and the quenching mechanism was determined to be Tb³⁺-Tb³⁺ inos exchange interactions.The fluorescent properties of the target were significantly enhanced by added molten salts.According to the comprehensive analysis,the optimal flux was determined to be the mixture of NaCl?5 wt% NaCl?and Na2SO4,and the mass ratio of mixture flux to precursor was 2:1.?2?The(Gd_1-xEu_x)AlO₃?x=0.005-0.07?perovskite solid solutions,calcined from their precursors synthesized via ammonium bicarbonate co-precipitation technology,exhibitted strong red emissions.The pure phase(Gd_1-xTb_x)AlO₃ phosphors can be obtained by calcined at 1000?,the phosphor expressed uniform morphology and good dispersion.The(Gd_1-xEu_x)AlO₃ phosphor exhibited strong red emission(5D0-7F2 electric dipole transition of Eu³⁺)upon UV excitation wavelength of 263 nm(the charge transfer band of O2--Eu³⁺).The 275 nm and 312 nm wavelength(8S7/2-6I2/3 and 8S7/2-6Pj transitions of Gd³⁺)appeared on the excitation spectrum suggests that the energy transfer process appeared between Gd³⁺ and Eu³⁺.The quenching contents of Eu³⁺ was determined to be ⁵ at% in GdAlO₃ solid solutions,and the quenching mechanism was determined to be Eu³⁺ ions exchange interactions.The fluorescent properties of the GdAlO₃:Eu³⁺ phosphors were significantly enhanced by increasing the calcining temperature and the addition contents of flux.?3?The(Gd_1-xDyx)AlO₃?x=0.01-0.05?and [(Gd_1-xTb_x)0.97Dy0.03]AlO₃?x=0.03-0.15?precursors were synthesized by ammonium bicarbonate co-precipitation technology,flowing calcined at high temperature.The GdAlO₃:Dy³⁺ phosphor exhibited strong yellow emission(corresponding to 4F9/2?6H13/2 transition of Dy³⁺)upon UV excitation at 352 nm(The f-f electric transition of Dy³⁺,6H15/2?5P7/2),the optimal doping amount was determined to be 3 at%.Under the optimum UV excitation of 275 nm(4f⁸-4f75d1 transition of Tb³⁺),the photoluminescence?PL?spectra of [(Gd_1-xTb_x)0.97Dy0.03]AlO₃ phospphors displayed excellent green emission at ⁵46nm(5D4-7F5 transition of Tb³⁺).The energy transfer process of Dy³⁺?Tb³⁺ was proved by comparing the fluorescence intensity of 546 nm of [(Gd_1-xTb_x)0.97Dy0.03]Al O₃ and(Gd_1-xTb_x)AlO₃ phosphors.