基于Li+和Al3+的WO3薄膜活性界面特性与电致变色性能研究

非晶中嵌有纳米晶WO3薄膜具有优异电致变色性能，因而被认为是构筑电致变色器件的理想候选材料。然而，电场调控下传导离子对WO3电致变色薄膜中活性界面作用机理仍然不清楚，从而制约着这类薄膜在器件中应用。基于此，本项目拟构建Li+/WO3和Al3+/WO3体系，利用多种原位技术，通过改变薄膜微结构、致密度、组成、表面化学特征，离子类型、浓度等手段研究基于Li+和Al3+的WO3薄膜活性界面特性与电致变色性能。利用原位透射电子显微镜研究Li+嵌入/脱嵌诱导非晶中嵌有纳米晶WO3结构转变特征及非晶相“缓冲效应”。揭示Li+和Al3+在WO3活性界面赝电容形成机制，扩散机制及诱导结构转变机制，阐明活性界面特性对电致变色性能影响机制。获得着色效率＞50 cm2C-1的基于Li+和Al3+电致变色薄膜及其器件。本项目将为高性能电致变色薄膜和器件研究提供理论依据和材料基础。

The nanocrystal-in-glass (nanocrystals embedded amorphous matrix) tungsten oxide (WO3) thin films are currently regarded as ideal candidates for electrochromic devices (ECDs) because of their excellent electrochromic (EC) performance. However, such tungsten oxide thin films usually show limited practical applications for ECDs, because the mechanism of the conduction ions acting on the active interface in the thin films by electric field modulation remain poorly known. Based on this issue, Li+/WO3 and Al3+/WO3 systems will be constructed using Li+ and Al3+ as the conduction ions, and WO3 as the host crystal framework. Using various in situ techniques, the characteristics of active interface and electrochromic performance of tungsten oxide electrochromic thin films based on Li+ and Al3+ will be investigated by altering the characteristics such as microstructures, packing densities, compostions, suface chemical states of the WO3 thin films, types and concentrations of conduction cation ions. The microscope evolution of structural transitions induced by Li+ into/from the nanocrytal-in-glass WO3 and the ‘buffering effect’ of the amorphous matrix will be performed by in situ TEM (transmission electron microscope). Mechanisms on the formation of pseudocapacitance, ion diffusion and ion-induced structural transition of the active interface caused by Li+ and Al3+ in WO3 thin film will be demonstrated. The mechanism of the effect of active interface characteristics on EC performance will be clarified. Based on Li+ and Al3+, the high performance WO3 EC thin films and ECDs with a high coloration efficiency of more than 50 cm2C-1 will be obtained. This project will provide theoretical basis and material foundations for the research and application of high performance EC thin films and ECDs.