离子掺杂对上转换光致发光薄膜组织与性能的影响

The sillicon solar cells, such as mono-Si, multi-Si, and α-Si,and so on, are sensitive to the visible light of the the solar spectrum, but not to the infrared light（850nm or above）accounting for 50% of the whole solar light energy. As the governing up-conversion material, the rare earth has been used in the photoluminescence glass, the optical fiber, and so on. In this project, Er3+、Eu3+、Tm3+ will be used as the exitation agent, Yb3+ as the sensitizing agent, and the oxides as the basic material, the optimal composition ratio for high up-convesion efficiency will be explored, as well as the up-convesion machanism. And the up-convesion photoluminescence thin film will be prepared on super clear glass or transparent conductive glass with sol-gel and spin-coating. The effects of one, two, or all of Er3+、Eu3+、Tm3+, on the absortion spectrum and the emission spectrum of the film, as well as those of the alkali metal, will be investigated. The mechanism of the infrared absorbtion, the energy transfer, and the visible light emission, will be explored. And the film will be tried to improve the the sillicon cells' efficiency.

硅太阳能电池（包括单晶、多晶、非晶等）对太阳光谱的可见光敏感，而对波长大于850nm、占总能量近50%的红外光不敏感。如果能将太阳光谱的红外光上转换为可见光，那么硅电池的效率将显著提高。稀土作为主要的上转换发光材料，已经广泛用于发光玻璃和光纤等。本项目拟以氧化物为基质材料，以Er3+、Eu3+、Tm3+等为激活剂，以Yb3+为敏化剂，以溶胶-凝胶、旋涂工艺在高透光玻璃上制备上转换光致发光薄膜。研究稀土离子的一元、二元、多元掺杂，对薄膜的吸收光谱域宽度、强度和发射光谱域宽度、强度的影响；研究碱金属离子对薄膜组织和性能的影响；探索基质、激活剂、敏化剂之间的相互作用，红外光的吸收、能量的转移以及可见光的发射机制。实现太阳光谱红外线对材料的有效上转换激发，制备可望用于提高太阳能电池效率的上转换膜

本项目分别以TiO2、TiO2/SiO2、ZnO为基质材料，以Er3+、Ho3+等为激活剂，以Yb3+为敏化剂，以溶胶-凝胶、旋涂工艺制备了上转换光致发光薄膜。研究了稀土离子的一元、二元、多元掺杂，对薄膜的吸收光谱域宽度、强度和发射光谱域宽度、强度的影响；研究了制膜工艺对薄膜组织和性能的影响；探索了基质、激活剂、敏化剂之间的相互作用，红外光的吸收、能量的转移以及可见光发射的机制。对于Er3+、Yb3+共掺的TiO2/SiO2膜，随着当Si/Ti摩尔比的减小，薄膜的近红外吸收度先增加后减小，薄膜的晶粒尺寸而先减小后增加, 薄膜为上转换发光强度先增加后减小，当Si/Ti摩尔比为1/8时，近红外吸收度最高，上转换发光强度最强。对于Er3+、Yb3+共掺的ZnO膜，随着Ho3+离子浓度增加，ZnO薄膜的上转换发光强度先增大后减小；随着Yb3+离子浓度的提高，ZnO薄膜的上转换发光强度先增大后减小；随着热处理温度的提高，薄膜的上转换发光性能先迅速提高而后减小。随着碱金属离子Li+浓度的增加，Er3+、Yb3+共掺的TiO2纳米晶发光强度首先成倍提高，然后下降。