稀土上转换/窄带半导体复合材料构筑及光学性质研究

Rare-earth doped upconversion luminescent materials have attracted extensive research interest in recent years due to their unique luminescent properties and potential application prospects. By combining rare-earth doped upconversion luminescent materials with semiconductor photocatalytic materials, the spectral response range of semiconductor photocatalyst was successfully extended from the visible region to the near-infrared region. However, photocatalytic efficiency of rare-earth doped fluoride upconversion materials/semiconductor composite photocatalyst is affected by the band gap of the traditional semiconductor photocatalyst and the luminescence efficiency of the rare-earth upconversion materials. This project intends to prepare rare-earth doped fluoride upconversion/narrowband semiconductor materials, witch to expand the absorption range of rare-earth doped fluoride upconversion materials by introducing narrowband sulfide semiconductor materials. In addition, the fluorescence intensity of rare-earth doped fluoride upconversion materials will improved by combining with the surface plasmon resonance (SPR) effect of noble metal nanostructures. Noble metal/ fluoride upconversion materials/sulfide semiconductor composite photocatalysts with excellent structure and performance were prepared. Analysis the influence of microstructure to the photocatalytic property. Moreover, the general low of the enhanced photocatalysis principle of precious metal/metal sulfide/rare earth-doped up-conversion materials will be discussed with the results of theoretical analysis. Finally, obtained near infrared response noble metal nanostructures/rare-earth doped fluoride upconversion/semiconductor sulfide semiconductor materials with high catalytic activity and cycle stability. This project will provide experimental basis and technical support for the application of these materials in the field of photocatalyst production by solar energy.

稀土掺杂上转换发光材料由于具有独特的发光特性和潜在的应用前景，近几年吸引了广泛的研究兴趣。然而，由于传统半导体光催化剂禁带宽度和稀土上转换发材料发光效率的限制，影响了稀土掺杂上转换发光材料/半导体复合光催化剂的光催化效率。本项目拟通过引入窄禁带硫化物半导体材料，扩宽对稀土掺杂上转换发光材料荧光光谱的吸收范围；并结合贵金属纳米结构的等离激元效应，提高稀土掺杂发光材料的荧光强度。制备出结构和性能优异的贵金属/稀土掺杂发光材料/硫化物复合光催化剂。分析材料微观结构对材料光学性能和光催化性能的影响。最后结合理论模拟深入分析贵金属/稀土掺杂发光材料/硫化物复合光催化材料光催化性能的增强机理，从而获得具有高催化活性和循环稳定性好的近红外响应贵金属/稀土掺杂发光材料/硫化物复合光催化剂，为稀土掺杂发光材料在光催化领域的应用提供实验依据和技术指导。

本项目提出将稀土掺杂上转换发光材料与半导体光催化材料复合，利用稀土掺杂材料独特的上转换发光性质，将红外光转换为半导体可吸收的光，进而扩宽光催化剂的光谱吸收范围，提高光催化剂的光催化效率。采用溶剂热方法制备了NaYF4:Yb3+,Er3+(Tm3+)纳米棒，并在其表面生长了硫化镉及贵金属颗粒，制备了贵金属/NaYF4:Yb3+,Er3+(Tm3+)/硫化物复合光催化剂，对材料进行了结构和性能测试，材料具有较好的结构特征，上转换发光性质也比较优异，但是在光催化产氢性质测试过程中，没有实现红外光照射下的光催化反应，还无法证明上转换荧光被用于光催化过程。.在制备贵金属/NaYF4:Yb3+,Er3+(Tm3+)/硫化物复合光催化剂的同时也从稀土掺杂上转换发光材料和光催化两个方向进行了相关研究，制备具有等离子体增强光催化累积效应的Au@Pt/CdS/C3N4二维半导体异质结，这种复合结构会基于Au纳米立方的表面等离子共振效应实现能量共振转移和“热电子”转移效应，从而促进光催化反应的电荷分离和电荷迁移过程。此外，大量的2D Au/CdS/ C3N4界面通过局域电磁场增强提高C3N4纳米片的电荷分离效率和活性位点的数量，也提高了复合材料的光催化反应的电荷利用效率，整体提高了复合光催化剂的光催化性能。制备Yb3+敏化La2Mo2O9荧光粉和一维Er3+-Yb3+-Mo6+共掺杂TiO2/Yb2Ti2O7复合纳米纤维，根据掺杂体系的典型热耦合和非热耦合能级评价光学温度传感性能，将材料用于光学温度传感时，具有较高的感温灵敏度。