摘要
采用Pechini溶胶 凝胶法合成了Sr2 CeO4 粉末。利用X射线衍射 (XRD)、扫描电镜 (SEM)、热重及差热分析 (TG DTA)以及发光光谱等测试手段对Sr2 CeO4 的结晶过程、发光性质进行了研究。XRD结果表明 ,用Pe chini溶胶 凝胶法合成的样品 80 0℃时已开始结晶 ,90 0℃时可得到三斜晶系的Sr2 CeO4 多晶粉末。扫描电镜照片可以看出颗粒大小不均匀 ,粒径约为 1～ 5 μm。发光光谱测试表明Sr2 CeO4 粉末的激发光谱是一个宽带双峰结构 ,分别位于 310nm和 34 0nm。这个宽带属于Ce4 + 的电荷迁移带。用 34 0nm激发样品 ,其发射光谱也是一个宽带 ,最大峰位于 475nm ,这个峰属于Ce4 + 的f→t1g跃迁。用 310nm激发得到的发射光谱与用 34 0nm激发得到的发射光谱相同。
Field emission displays (FEDs) offer the potential of achieving comparable or superior levels of performance to the cathode ray tubes (CRTs). However, FEDs must operate at significantly lower excitation voltages (≤5kV) and higher current densities (10～100A/cm 2) than that of CRTs. Thus the phosphors for FEDs are required to have a high efficiency at low voltages, high resistance saturation, long service time, and equal or better chromaticity than that of CRT phosphors. For full color flat panel displays, vary satisfactory red and green commercial phosphors are being produced by the f→f transitions of Tb 3+ and Eu 3+, but suitable blue phosphors are still lacking, because wide band gap materials are required and the eye sensitivity is quite low in the blue spectra region. Sr 2CeO 4 is an efficient blue phosphor found by combinatorial method and prepared by the decomposition of carbonates, acetates and oxalates. But these methods always were realized at temperatures above 1 000℃ for a period as long as 48h. The sol-gel method, because of its apparent advantages of fine homogeneity, high reactivity of starting materials and lower sintering temperature, is a new route to synthesize fine powders. It has attracted more and more attention. The method was widely used to prepare multicomponent oxides, such as superconductors etc. In this paper, Sr 2CeO 4 phosphors were prepared by a Pechini sol-gel method via inorganic precursors Sr(NO 3) 2 and Ce(NO 3) 3 together with organic chelating agent citric acid and cross-linking agent polyethylene glycol (PEG). X-ray diffraction (XRD), scanning electron microscope (SEM), and photoluminescence spectra were used to characterize the Sr 2CeO 4 phosphors. The results of XRD show that the crystallization of Sr 2CeO 4 begins at about 800℃, completes around 900℃ with a triclinic structure. SEM studies show that the 900℃ annealed samples are well crystallized, with grain size range from 1μm to 5μm. The excitation spectrum of Sr 2CeO 4
出处
《发光学报》
EI
CAS
CSCD
北大核心
2003年第1期91-94,共4页
Chinese Journal of Luminescence
基金
中科院百人计划和杰出青年科学基金资助项目
