低温燃烧合成Sr_(1.93)Ba_(0.05)SiO_4:Eu荧光粉及其发光性能

Low temperature combustion synthesis and luminescence of Sr_(1.93)Ba_(0.05)SiO_4:Eu phosphor

以尿素为燃料，金属硝酸盐为氧化剂，（C2H5O）4Si为硅源，采用低温燃烧及回火还原处理合成用于白光LED的Sr1.93Ba0.05SiO4：Eu荧光粉。讨论助熔剂SrCl2用量和回火温度对荧光粉相组成的影响，研究合成产物的发光性能，初步提出合成反应机制。燃烧合成中熔融的SrCl2：为整个反应提供了一个半流动态的环境，促使生成的杂相SrCO3，分解。低温燃烧直接产物Sr1.93Ba0.05SiO4：0．02Eu^3＋非晶材料在波长393nm近紫外光的激发下最强发射峰值是波长为612nm红光；处理后晶相产物Srl93Ba0.05SiO4：0．02Eu^2＋发射峰值是波长为480nm的蓝光和543nm的黄绿光，分别是由处于不同格位上的Eu2＋（Ⅱ）和Eu＾2＋（I）的5d→4f跃迁产生的。用不同的近紫外光（380-410nm）激发时，样品发射出的蓝光（480nm）和黄绿光（543nm）的强度都随着激发光波长的增大而减小，而且蓝光的强度减小非常明显，同时，随着激发光波长的增大黄绿光波长增大。

The Srl.93Ba0.05SiO4：Eu phosphors for white-light-emitting diodes were synthesized using low temperature combustion method. The influences of the amount of the flux SrClz and calcining temperature on the phase compositions of the products were studied and their photoluminescence was investigated. The reaction mechanism was proposed initially. The SrC12 flux not only provides a semi-dynamic environment in which the combustion reaction takes place, but also avoids the unintended phase SrCO3. Amorphous material Srl.93Ba0.osSiOa：0.02Eu3＋ emits the strongest peak at 612 nm red light when it is excited in the 393 nm near ultraviolet （UV） light. The emission spectrum of Srl.93Ba0.05SiOa：0.02Eu2＋ fabricated by the low temperature combustion method and calcined in reducing atmosphere shows a green-yellow broadband emission peak at around 543 nm and a blue band at 480 nm, which are respectively generated by the 5d→4f transitions of the Eu2＋ （Ⅱ） and Eu^2＋ （I） at different lattice positions. When excited with near UV （380-410 nm）, the intensity of the blue light （480 nm） and yellow green light （543 nm） increases with the decrease of the excitation wavelength, and the intensity of the blue light decreases obviously, and at the same time, with the increase of the excitation wavelength, the wavelength of the yellow-green light emitted increases.