Synthesis And Photoluminescent Properties Of Rare Earth Doped Glass-ceramics Containing Gallate?Aluminate And Silicates Nanocrystals

The MgO-Ga₂O₃-SiO₂,MgO-Al2O3-SiO₂ and SrO-Al2O3-SiO₂ glass-ceramics containing MgB2O4?B=Ga, Al? and Sr2SiO4 nanocrystals were prepared successfully with the sol-gel method. By changing the compesition of glass, conditions of heat treatment and the types or concentration of doped rare earth, the photoluminescent properties can be modulated and the high efficient emission can be obtained. The composition, heat treatment temperature and concentration of doped rare earth which have great effect on the microstructure and photoluminescent properties of samples have been studied. The main results are as follws:?1? With analyzing the structures and luminescent performances, the effect that as the content of MgO-Ga₂O₃, MgO-Al2O3 and SrO is changed on the structure and luminescent properties of glass-ceramics has been studied. It shows that as the content of MgO, SrO, Ga₂O₃, Al2O3 is increased, the MgGa₂O₄, MgAl2O3, Sr2SiO4 nanocrystals can be easily obtained. It is found that the emission intensity can hance as the content of MgO-Ga₂O₃, MgO-Al2O3, SrO increased.?2? The effects of different heat-treatment temperatures on the sturucture and luminescent properties of glass-ceramics have been studied. The MgGa₂O₄, MgAl2O4, Sr2SiO4 nanocrystals become larger with increasing the temperature, resulting in the accumulation of nanocrystals. The emission intensity is enhanced with the increase of temperature. As the temperature is further increased, the emission intensity becomes weak. It implys that the anneal temperature has great effect on the structure and photoluminescent performances.?3? As different rare earth ions and the concentration are doped and changed, the effects of rare earth on the structure and luminescent performance have been studied. The results show that the few rare earth ions can not change the structure of nancrystals in glass-ceramics. For the Eu³⁺/Dy³⁺ doped samples, the characteristic emission Eu³⁺ can be observed, which originates from 5D0-7Fj?j=0, 1, 2, 3, 4?. And the emission peaks locating at 480 nm, 580 nm and 665 nm are come from the transition of Dy³⁺, which indicates the Eu³⁺/Dy³⁺ co-doped glass-ceramics may be potentially applied to the white LED. For the Er³⁺/Yb³⁺ co-doped samples, the energy transfer from Yb³⁺ to Er³⁺ can be observed, and with inceasing the concentration of Yb³⁺, the emission of Er³⁺ is enhanced, at the same time, the two-photon upconversion process was comfirmed in the Er³⁺/Yb³⁺ system.