CaO-SiO_2:Eu^(3+),Bi^(3+)低温合成及其发光行为

LOW TEMPERATURE SYNTHESIS OF CaO-SiO_2:Eu^(3+),Bi^(3+)AND ITS LUMINESCENCE BEHAVIOUR

以高纯的 Eu_2O_3,金属 Bi,CaCO_3,Li_2CO_3以及 Si(OC_2H_5)_4(A.R.)为原料,采用溶胶-凝胶法,合成 CaO-SiO_2:Eu^(3+),Bi^(3+)。合成温度较高温固相反应法低300—400℃。最佳组成为0.89CaO-SiO_2:0.045Eu^(3+),0.01Bi(3+)。利用红外光谱、X 射线粉末衍射谱、热重及差热分析研究了由凝胶向发光晶体的转变过程。通过激发光谱和发光光谱的研究,发现 Bi^(3+)离子向 Eu^(3+)离子的能量转移是十分有效的。

The luminophors CaO-SiO_2:Eu^(3+),Bi^(3+)were synthesised by sol-gel method.The reactants are Eu^2O_3,Bi,CaCO_3,Li_2CO_3and Si(OC_2H_5)_4.In the sol-gel method the reac-tion temperature is lower than that in solid phase reaction.The optimum chemical composi-tion of the luminophor is 0.89CaO-SiO_2:0.045Eu^(3+),0.01Bi^(3+)with the monoclinic system.Thetransfer process from the gel to crystal was studied by TG-DTA,XRD and IR spectra.Ac-cording to the intensity ratio of ~5D_0-~7F_1 to ~5D_0-~7F_2 transition,it is known thatEu^(3+) ions lie in the nonsymmetrical site in the host lattice.Owing to the face that the emis-sion peak of Bi^(3+) ions in CaO-SiO_2:Bi^(3+) and the absorption peak of Eu^(3+) ions inCaO-SiO_2:Eu^(3+) are overlapped,the energy transfer happens from Bi^(3+) to Eu^(3+) ions.