溶胶-凝胶法制备稀土离子掺杂氯硅酸钙及其性能优化

It has important science mean and practical value for improving the luminescent effect and stability to prepare the novel near UV based phosphor used for white LED. This project will fabricate a series of calcium chlorosilicate phosphors. The effects of substrate components, activator or complexant kinds, the PH value of reaction solution and the sintering temperature on the luminescent properties correlated color temperature and color rendering index etc. are studied by measuring the sample components, morphology, excitation, emission, luminescent lifetime and quantum efficiency. The electronic structures, density of states of different materials are calculated using first-principles, by which analyzes the relation between the substrate components and luminescent properties. In this project, we will improve the technological process of preparation of calcium chlorosilicate phosphor by sol-gel method; prepare the luminescent material with higher color purity, a narrow particle distribution, regular morphology, higher quantum efficiency and well stability; reveal the site occupancy of activator in the host and the energy transfer mechanism of different activator. This project has important academic significance for improving the preparation technology of luminescent material and enhancing the efficiency of LED device, perfecting the luminescent mechanism of rear earth doping chlorosilicate phosphors.

研制新型可被近紫外激发的白光LED用荧光粉对于提高LED的发光效率和稳定性具有重要的科学意义和实用价值。本项目拟采用溶胶-凝胶法制备出系列稀土离子掺杂的氯硅酸钙荧光材料。通过对样品组分、形貌、激发光谱、发射光谱、荧光寿命和量子效率等的测量，研究基质组分、激活剂及络合剂种类、反应溶液PH值、烧结温度等条件对荧光粉发光性能及相关色温、显色指数等色参数的影响；利用第一性原理方法计算不同基质组分的电子能带结构、态密度等，研究基质组分的改变对发光性能的影响。项目预期探索出溶胶-凝胶法制备氯硅酸钙荧光材料的最佳工艺条件，制备色纯度好、量子效率高、稳定性好、粒度分布较窄、形貌规整的发光材料，揭示激活剂在基质中的占位、共激活剂间的能量传递机理以及基质组分与荧光粉发光性能之间的关系。本项目对于改进发光材料的制备工艺，提高白光LED器件的效率，完善稀土离子掺杂氯硅酸盐荧光材料的发光机理具有重要的学术意义。

本课题通过溶胶凝胶法制备了稀土离子Sm3+, Dy3+及Eu2+掺杂Ca3SiO4Cl2荧光粉，测试了荧光粉的激发光谱和发射光谱。结果表明这些荧光粉在紫外激发下可以发出较好的蓝色、黄色及红色光。研究了不同激活剂浓度对荧光粉发光性能的影响，得到了最佳掺杂浓度，并分析了浓度猝灭机理。通过优化过程条件、使用不同助熔剂和电荷补偿剂改善了样品的发光性能。得到了溶胶凝胶法制备氯硅酸盐荧光粉的最佳条件。通过第一性原理计算了基质材料的能带结构、态密度，解释了不同基质材料的电子结构。在此基础上，利用溶胶凝胶法制备了Ba5SiO4Cl6:Eu2+荧光粉，并通过Ca2+和Sr2+离子替代Ba2+离子，研究了基质替代对荧光粉发光性能的影响。利用溶胶凝胶法制备了Sr2SiO4:Eu2+荧光粉，研究了不同粒径与结构和发光的关系。利用水热法制备了Eu3+离子激活的Sr3Al2O6荧光粉并测试了其发光性能，得到了水热法制备荧光粉的工艺条件。通过本课题的研究，完善了溶胶凝胶法等湿化学法制备荧光粉的工艺条件，并对第一性原理对基质材料的电子性质计算进行了初步探索，为荧光粉基质材料的电学性质研究有一定的指导意义。