【作者】 陈绍军；

【导师】 刘晓华；

【作者基本信息】 汕头大学 ， 材料物理与化学， 2006， 硕士

【摘要】 通过高温固相反应法制备了掺Eu³⁺基质为CeO₂的发光粉系列样品并对其做了X射线衍射谱（XRD）和光致发光谱（PL）检测。XRD结果表明在Eu³⁺掺杂浓度为0.2?10at．％的范围内，Eu³⁺完全进入了CeO₂的晶格，形成固溶体Ce_1-xEu_xO₂；PL谱表明Eu³⁺的发射峰强度依赖于Eu³⁺的掺杂浓度，在Eu³⁺的含量为1at．％时最强，随后出现浓度猝灭。 采用高温固相反应法和溶胶-凝胶法（sol-gel）合成了新型发光材料SrCeO₃：Eu³⁺。研究了材料制备的相变过程以及材料的结构性质和发光特性。对于采用sol-gel法制备了SrCeO₃：Eu³⁺发光粉，TG-DTA和XRD分析结果表明钙钛矿结构的SrCeO₃：Eu³⁺形成于850℃左右；1000℃焙烧的样品以SrCeO₃为主晶相，伴随有少量Sr2CeO₄和CeO₂杂相；1250℃焙烧的样品为SrCeO₃钙钛矿结构并含有极少量CeO₂杂相。分析表明，在干凝胶高温焙烧过程中，SrO的过量蒸发导致了由sol-gel法制备的SrCeO₃：Eu³⁺中残留少量的CeO₂相。因而在采用sol-gel法制备SrCeO₃：Eu³⁺发光粉时，起始反应物中SrCO₃应有适当过量为宜。 采用sol-gel法制备的SrCeO₃：Eu³⁺样品的激发光谱由峰值位于～239、～258nm激发带和270—320nm宽激发带组成。其中270—320nm激发带为Eu³⁺-O^2-的电荷迁移带和基质Ce⁴⁺-O^2-电荷迁移带的叠加。短波区的两个激发带起源于基质的能量吸收。各激发带对应的发射光谱均以⁵D₀—⁷F₁跃迁为主。 对于通过高温固相反应法制备的不同组分的SrCeO₃：Eu³⁺发光粉。研究了EH³⁺离子在SrCeO₃晶格中的替代规律。光谱分析表明～239nm和～258nm激发带起源于基质的紫外吸收；～273nm、～298nm的激发带为Eu³⁺-O^2-的电荷迁移带；～285nm和～310nm激发带属于ce⁴⁺-O^2-的电荷迁移带。发射峰强度随Eu³⁺掺杂浓度从0.5at．％到15at．％逐渐增强，在15at．％时最强，没有出现浓度猝灭。在Eu³⁺浓度少于5at．％的样品中，⁵D₀—⁷F₁跃迁比⁵D₀—⁷F₂跃迁强，在Eu³⁺浓度超过5at．％的样品中，⁵D₀—⁷F₂跃迁比⁵D₀—⁷F₁跃迁强。SrCeO₃：Eu³⁺发光粉样品对不同激发波长表现出不同的发射强度。更多还原

【Abstract】 CeO₂:Eu³⁺ phosphor powders with various Eu³⁺ concentrations have been synthesized by the solid state reaction method. X-ray diffraction （XRD） analysis showed the formation of pure solid solution Ce_1-xEu_xO₂ up to 10at.% concentration of Eu³⁺. The Photoluminescence （PL） measurements indicated the dependence of PL emission intensity on the Eu³⁺ concentrations. The CeO-2:Eu³⁺ phosphor powders showed the strongest photoluminescence for 1 at.% concentration of Eu³⁺ and then abruptly decreased indicating the concentration quenching.SrCeO₃:Eu³⁺ phosphor powders have been synthesized by the sol-gel method and solid state reaction method. TG-DTA and XRD were employed to analyze the synthesis process and the crystalline structure of SrCeO₃:Eu³⁺ powders. SrCeO₃:Eu³⁺ phosphor powders with almost pure perovskite phase were obtained at sintering temperature of 1250°C. The detailed analysis demonstrated that Eu³⁺ ions mainly occupy the Ce⁴⁺ sites in SrCeO₃ lattice.The Photoluminescence （PL） measurements indicated the dependence of PL emission intensity on the Eu³⁺ concentrations. The excitation spectra of SrCeO₃:Eu³⁺ consist of a series of excitation bands. Among these bands, the ones at ²39nm and ²58nm originate from ultraviolet absorption of the host; the bands at ²73nm and ²98nm are Eu³⁺-O^2- charge transition band （CTB）, and the bands at ²85nm and ³10nm are Ce⁴⁺-O^2- CTB. The emission spectra of SrCeO₃:Eu³⁺ showed Do-⁷F₁ and ⁵D₀-⁷F₂ transitions of Eu³⁺ are the strongest emissions for the samples with Eu³⁺ concentration of 15at.% and no concentration quenching was observed. The sample with 5at.% Eu³⁺ exhibited the strongest emission band centered at 422nm. The emission intensities of SrCeO₃:Eu³⁺ powders showed obvious dependence on the excitation wavelength. The sensitive excitation wavelengths for the emissions at 422nm, 370-470nm and 4f transitions of Eu³⁺ are 236nm, 241nm and 290nm, respectively.更多还原