π共轭分子界面结构及电荷转移的分子机制的原位SPM研究

During the past decades, organic semiconductors have attracted wide interests for its special optical, electric and magnetic properties. The performance of organic semiconductors not only determined by molecular structure and properties but also depends on the molecular packing and the interface between the molecules and the electrode surface. By using in-situ scanning probe microscopy (STM, AFM, STS) and other techniques, this project aims to investigate the structure and charge transfer process at the interface between organic semiconductors and electrode surface, reveal the relationship between the performance of organic semiconductors and interfacial structure. The main contents include: (1) study the formation of functional interface based on π-conjugated molecules, understand the relationship between the molecualr packing at the interface and the molcule-molecule and molecule-surface interactions;(2) in-situ investigate the electron transfer process between redox active molecules and electrode surface, clarify the micro mechanism of charge transfer at the interface; (3) research the interfacial electrical transport properties of π-conjugated molecules, summarize the correlation of interfacial electrical transport properties to the interfacial structure; (4) control the molecular packing and electrical transport properties of specific molecules by using buffer layers or other external fields, explore possible affect mechanism, provide theroy foundation for the design and construction of organic semiconductor devices with high performance.

由于具有特殊的光、电、磁性质，有机半导体近年来受到广泛关注。有机半导体的性能不仅取决于分子本身的结构性质，与分子聚集体中分子的堆积模式及分子与电极间的界面也密切相关。本项目拟以扫描探针显微技术（STM、AFM、STS等）为主要研究方法，原位研究有机分子与电极界面的结构及电荷转移过程，揭示分子界面电输运特性与分子在电极表面的堆积模式的联系，主要内容包括：（1）研究π共轭分子功能界面的形成，理解分子与电极表面间以及分子间相互作用对分子堆积模式的调控作用；（2）原位研究π共轭分子与电极界面的电荷转移过程，探索界面电荷转移的分子机制；（3）考察π共轭分子的界面电输运特性，揭示分子与电极界面的结构与电输运特性的联系；（4）利用修饰层或光、电、热等外场条件实现对特定π共轭分子体系的调控，研究调控过程的作用机制，理解有机半导体器件工作过程中结构性能的变化关系，为高性能半导体器件的设计构筑提供理论基础。

研究有机分子在电极界面的结构及其调控，揭示有机分子在电极界面的电学性质及反应，对有机半导体器件性能的提高及其设计构筑具有重要意义。本项目研究了硫代轮烯、卟啉等π共轭有机分子在电极表面的组装，获得了基于卟啉分子的双组分棋盘结构和双层异质结构；设计构筑了基于四硫富瓦烯分子和基于卟啉分子的表面共价框架结构；首次实现了在实空间中对电子转移前后的单个电子给体-受体复合物进行鉴别，从单分子水平研究了电子给体-受体复合物与金属电极间的电子转移过程，揭示了界面驱动力与界面电子转移反应间的关系；测量了共轭分子形成的双硫键二聚体分子结的单分子电导性质；原位研究了钴卟啉分子催化氧还原反应；此外，还对铜锌锡硫硒及钙钛矿薄膜表界面微区电学性质进行了原位AFM研究，在纳米尺度上直观地分析了薄膜微区结构和电学信息。通过本项目的实施，项目组发表相关学术论文26篇，包括J. Am. Chem. Soc. 3篇，Angew. Chem. In. Ed 1篇。.