基于局域表面等离子激元共振的TiN/ZnO超材料的设计、制备、性质及光催化器件研究

ZnO nanoparticles have been regarded as a promising air-/water-purification material owing to their outstanding photocatalytic properties. However, the photocalatytic effect can only be activated by ultraviolet light due to the wide band gap of ZnO. In fact, only 10 % of energy can be used when ZnO nanoparticle based photocatalytic devices being irradiated by sunlight, making the efficiency very low. In order to solve the problem, we have proposed the introduction of titanium nitride (TiN) and gallium zinc oxide (GZO) nanocomposite to improve the absorption efficiency of sunlight of the ZnO based photocatalytic devices. As is known, localized surfaced plasmon resonance could be activated by an external electromagnetic wave in n-type heavily doped TiN and GZO nano-structures. By proper design of the structures of the TiN/GZO metamaterial, the electrical and optical properties of the nanocomposite can be tuned to optimize the absorption efficiency to the visible and near-infrared band of sunlight. For device design, we have proposed the idea to realize an active device by applying an electric field between the TiN/GZO metamaterial and ZnO nanoparticle film. This design can significantly improve the separation efficiency of the photogenerated electrons and holes, and thus will reduce the recombination rate of carriers. The proposed ZnO photocatalytic device based on TiN/GZO nanocomposites can eventually realize efficient degradation to the harmful gases (carbon, sulfur, and nitric oxide) in haze.

ZnO的纳米颗粒因其具备出色的光催化性质被认为是空气和水净化的优选材料。然而由于其禁带较宽，需要紫外光激发才能实用。在更具吸引力的太阳光照下，仅10%的能量可被利用，致使ZnO纳米颗粒的太阳光催化效率很低。针对这一问题，我们提出引入与ZnO晶格和性质兼容的TiN/GZO超材料来大幅增加ZnO基光催化器件对太阳光谱的有效吸收。项目利用n型重掺杂TiN和GZO材料在纳米尺度时可被外加电磁波激发表面等离子体激元振荡的物理特性，通过TiN/GZO超材料的纳米结构设计，调制TiN/GZO的电学和光学性质，实现对太阳光中可见和近红外波段的优化吸收。在器件层面，项目针对目前光催化器件中载流子再复合率高的问题，提出在纳米阵列化的TiN/GZO超材料与ZnO纳米颗粒膜间施加电场以进一步增加光生载流子分离效率，实现有源器件的构想，并最终实现器件在太阳光照下对雾霾气体(碳、硫、氮氧化物)的有效降解。

太阳能作为一种可持续的清洁能源，其收集和转化一直以来都获得人们的关注。项目以此为研究动机，主要开展了基于TiN-ZnO复合材料的太阳光收集和转化器件研究，具体包括ZnO和TiN的材料性质研究，复合材料制备，太阳光收集转化器件设计制备和测试。取得了如下主要成果：(1)阐明了ZnO材料复杂的本征缺陷形成机理；(2)获得了具有类金属性质的高质量TiN材料；(3)验证并调控了TiN的太阳光谱吸收性质；(4)TiN-ZnO复合材料中，实现了TiN局域表面等离子激元激发电子向ZnO的转移；(5)制备了基于TiN-ZnO-AAO的太阳光催化器件，性能优于传统贵金属-ZnO复合结构器件；(6)研发了多种基于TiN选择性吸收体等吸光材料的太阳能光热转化水蒸气产生器件。研究结果充分展现了TiN-ZnO复合材料做为太阳光收集转化材料体系的优势，完成了项目计划并外延出新的太阳光收集转化思路，为项目的进一步延伸奠定了基础。