可见光LED激发UVC紫外上转换发光材料的制备及研究

本项目首次提出了采用可见光LED作为激发源，激发上转换发光材料产生UVC紫外上转换光发射方法。它在污水处理、粮食和食物的防霉等方面有着潜在的应用价值。由于在LED 激发下UVC紫外上转换光发射效率还很低，获得具有高效的UVC上转换的发光材料是该材料得以实际应用的前提。 本项目把获得在可见光LED激发下产生高效UVC上转换材料作为目标。拟从发光中心、基质、敏化剂三个方面入手。根据上转换机理和对亚稳态能级寿命要求，把发光中心范围限定为稀土离子；基质材料限定在鋅酸盐、氟化物、铟酸盐和硫化物这些具有较低声子能量的基质材料；敏化剂采取三种方案，分别为，1）采用在可见光波段有较大吸收截面的稀土离子，2）采用过渡族元素，3）采用在可见光有等离子吸收的金属元素。通过筛选获得理想的可见光LED激发在UVC有较高发射效率的基质发光中心和敏化剂，并通过细菌实验验证杀菌效果

In this project, we present a new approach for the first time to achieve intense UV upconversion emission excited by a visible light LED, which has potential application in sewage disposal, mould inhibition of grain and other foodstuffs.However,high efficiency of UVC upconversion is the precondition of the practical applications for these materials. Our target is to obtain the UVC upconversion material with high efficiency.We will start with three aspects of luminescence centers, host materials and sensitizers. The luminescence centers are restricted to rare earth ions according to the mechanism of upconversion emission and the requirement of the metastable levels. The host materials are restricted to zinc acid salt,fluoride, indium acid acid and sulfide with their lower phonon energy. Three schemes are adopted to obtain suitable sensitizers by rare earth ions with higher absorption cross section in visible light, transition element as well as metal atoms by the surface plasmon. The suitable luminescence centers,host material and sensitizers is obtain by selection process and the germicidal efficacy of the UVC upconversion material is verified by the experiment.