广谱光吸收的上转换发光增强3C-SiC纳米复合结构设计及光解水研究

为最大程度利用太阳光，将"上转换(UP)发光增强光吸收"的思想引入光解水体系的设计中，选择特点突出的3C-SiC纳米晶为光催化材料，将其与UP发光材料有机结合，通过对UP发光材料发光行为进行调谐，获得具有广谱光吸收能力和高光催化活性的UP发光稀土氧化物/3C-SiC纳米复合结构，并将其与离子掺杂TiO2纳米管阵列结合，构建自驱动光解水系统。本项目以UP稀土氧化物/3C-SiC纳米复合结构的设计与制备研究为前提，重点研究3C-SiC纳米晶结构及表面特性等对其能带结构及光谱响应特性的影响规律；探索UP纳米材料发光行为（激发与发射）的调谐机制；通过纳米复合结构设计揭示UP发光对3C-SiC光谱响应的增强机理；分析3C-SiC纳米晶表面结构及其与水分子的相互作用机理；探讨3C-SiC纳米晶中载流子的产生、输运及运达表面后与水分子的相互作用及调控机制，提出新型高效光解水系统的设计新原理。

In order to maximize the use of sunlight, the idea of upconversion luminescence enhanced light absorption of photocatalytic materials is introduced to the design of new style water splitting system. Choosing 3C-SiC nanocrystals with excellent properties as photocatalystic materials, upconversion luminescence nano-materials with tuned luminescence properties is combined with 3C-SiC nanocrystals to form upconversion luminescence materials/3C-SiC nanocrystal composite structure with broad spectrum light absorption ability and high photocatalytic activity, and then connected with ion doped TiO2 nanotube arrays with outstanding characters to constructure new style self-driven water splitting system. The effects of size, microstructure and surface characters of 3C-SiC nanocrystals on their band gap structure and spectral response characteristics are analyzed mainly based on the design and preparation of upconversion luminescence enhanced 3C-SiC nanocrystal composite structure in this project. The regulation and control principle of luminescence behavior of rare earth elements doping upconversion nanomaterials is explored, and the effect of spatial distribution of upconversion luminescence nano-materials and 3C-SiC nanocrystals on photon transportation and absorption process in the composite structure, in other words, the enhancement role of upconversion luminescence to light absorption of 3C-SiC nanocrystal, is also analyzed here. The formation, transportation of charge carriers in 3C-SiC nanocrystals and TiO2 nanotube as well as the interaction of charge carriers with water molecules when they reach their surfaces are researched. At last, the design principle of new style water splitting system with high conversion efficiency is also proposed in this project.