Synthesis And Characterization Of Gallate Phosphors Doped With Rare Earth For White LEDs Application

MGa2O4(M=Mg,Ba,Sr, Ca, Zn) phosphors doped with rare earth (RE) were prepared successfully through solid state method, sol-gel synthesis, and hydrothermal route. Also the factors of the amount of RE doped, the temperature of heat treatment, the amount of MgO-Ga2O3and the synthesis ways on the micro-structure and fluorescence properties were studied systematically. The main research orientation and the adopted methods just as follows:(1) Several concentrations Eu3+-doped and Dy3+-doped MGa2O4(M=Mg,Ba,Sr, Ca, Zn) phosphors were prepared successfully by two-step firing synthesis. The sintered samples were characterized by means of X-ray diffraction (XRD) and fluorescence spectrophotometer. Little amount of rare earth doped will not change the host matrix structure and the maximum of the emission or excitation intensity of these phosphors will decrease as the concentration increasing for concentration quenching. The emissions of Eu3+caused by the transitions of5D0-7Fj (j=0,1,2,3,4) were observed. And there are three groups of emission at480nm,575nm and665nm occurring at the spectrum of Dy3+ions, which shows that MgGa2O4phosphors doped with nanostructures ions have the potentiality to be applied for white LEDs applications.(2) The MgO-Ga2O3-SiO2glasses and nanocrystalline glass-ceramic (GC) containing MgGa2O4nanocrystals doping with Eu3+or Dy3+ions were prepared by a simple sol-gel method. The affects of the amount of MgO and Ga2O3and heated temperatures on the structure of prepared samples were studied. The strong red luminescence of Eu3+in MgO-Ga2O3-SiO2glasses and GC was observed, and white light emission of MgO-Ga2O3-SiO2containing MgGa2O4nanocrystals GC doped with Dy3+ions is observed as excited MgGa2O4nanocrystals.(3) The MgGa2O4nanocrystals doped with different concentrations of RE were synthesized through the hydrothermal ways. The results of XRD analysis and fluorescence tests were different from the results above, which shows that the synthesis route would have an impact on the micro-structure and fluorescence properties.