研究开发满足未来高灵敏度、集成化、实时在线监测需求的水质化学需氧量（COD）检测方法及传感器是水环境监测领域研究的重要课题。本项目将典型的光电催化技术和新型的薄膜晶体管器件有机结合，选择具有光催化活性的金属氧化物半导体作为栅极构建基于薄膜晶体管的光电催化COD传感器。从栅极的结构调控入手，改变栅极材料组成结构、微观几何结构、表面/界面结构和能级结构，研究栅极/电解液界面结构与电极电容的关系，探明界面电容对界面电势分布的影响规律以及对沟道电流响应信号的调控机理，找到通过栅极界面结构优化提高传感器性能的方法。深入研究栅极光催化反应对传感器性能的影响机制，通过栅极光催化材料的精细设计达到对光电催化COD传感器检测性能的可控调制，改善传感器的响应恢复性能和拓宽检测范围，实现对水体COD值高灵敏度、高选择性、快速响应的实时在线检测，并且为薄膜晶体管光电催化传感器的推广应用奠定科学与技术基础。

Research and development of highly sensitive, integratable and online real-time monitoring methods and sensors for chemical oxygen demand (COD) determination are crucial for the reliable monitoring applications in water environment. The photoelectrocatalytic COD sensors based on the thin-film transistors are proposed in the project using the photocatalytic metal-oxide semiconductors as the gate electrode. The sensors combine the advantages of both the typical photoelectrocatalytic COD sensors and the thin-film transistors. The rational design and modification of the gate electrodes, including changing the materials composition, microstructure, surface/interface nature and energy-level alignment, are of great significance to improve the COD detection properties. These thus require a systematic study on the relationship among the materials preparation, structure modification, surface decoration and the corresponding photoelectrocatalytic COD determination. The influence of COD photoelectrocatalysis at the gate surface on the sensing properties will be further investigated. The relationship between the capacitance at the gate/electrolyte interface and the response current in the channel will also be explored to clarify the underlying sensing mechanism, which is beneficial to improve the response and recovery performance and to broaden the detection range of the COD sensors. The purpose of the project is to achieve a real-time online COD determination method with high sensitivity, high selectivity and fast response using the photoelectrocatalytic sensors based on the thin-film transistors.