硫脲用量对燃烧法制备的Y2O2S:Sm3+发光性能的影响

利用硫脲作为燃料(fuel,F),以Sm(NO3)3·6H2O,Y(NO3)3·6H2O为氧化剂(oxidizer,O),通过燃烧法制备了白光发光二极管用Y2O2S:Sm3+红色荧光粉,并研究了其发光性能以及硫脲用量等反应条件对发光性能的影响.X射线衍射结果表明:当燃料与氧化剂的摩尔比[n(F)/n(O)]为2.0～4.0时,通过燃烧法可合成纯相Y2O2S.n(F)/n(O)的值对样品的反应速度和反应温度有很大的影响.扫描电镜结果表明:当n(F)/n(O)为3.0时,可以得到粒度和发光强度较好的Y2O2S:Sm3+荧光粉.测量了Sm3+离子摩尔分数为3%时的激发光谱和发射光谱.样品的激发光谱由1个宽带和一系列的尖峰组成,其中位于412nm和468nm处的激发峰最强.发射光谱由3个发射带组成,其中发射主峰分别位于570nm,606nm和658nm.这表明Y2O2S:Sm3+可被波长为412nm的紫光和468nm的蓝光有效的激发并发出红光.

INFLUENCES OF SULFOUREA ON THE LUMINESCENCE PROPERTIES OF Y_2O_2S:Sm~(3+) PHOSPHOR SYNTHESIZED BY COMBUSTION METHOD

Powder phosphor Y2O2S:Sm3+ used for white light emitting diodes was synthesized through combustion process using Sm(NO3)3·6H2O, Y(NO3)3·6H2O as raw materials (oxidizer, O) and sulfourea (CH4N2S) as a fuel (F). The fuel to oxidizer mole ratio (n(F)/n(O)) has a direct effect on the luminescence properties of the phosphor. X-ray diffraction patterns reveal that the single Y2O2S phase was directly obtained from the combustion reaction with n(F)/n(O) of 2.0-4.0. The experimental results show that the Y2O2S:Sm3+ phosphor has a better emission intensity and optimum crystallite size when n(F)/n(O) equals 3.0. The excitation spectrum of the sample is composed of a broad band and a series of narrow peaks, in which the stronger peaks are located at 412 and 468 nm.The emission spectrum consists of three groups of narrow bands, in which the emission peaks are located at 570, 606 and 658 nm. The results indicate that the phosphor can be excited by ultraviolet light (412 nm) or blue light (468 nm) and emit red light.