基于电化学门控-机械可控裂结技术的单团簇电输运性质研究

Understanding the rule of charge transport through single nanocluster under nanometer even subnanometer scale is significant for revealing the novel physical and chemical properties of nanocluster materials, which also become an important frontier in the cross-study of cluster chemistry and physical chemistry in the world. Electrical properties of nanomaterials structure are sensitive to component, geometrical structure, electronic structure and surrounding environment of the detected sample. Thus, investigating the charge transport properties through single nanocluster can offer us the access to recognize the fundamental nature of these important transition state material structures, and to develop the applications of the single cluster in the electronics field. This project will design and build an electrochemical gating mechanically controlled break junction equipment and realize accurate detecting and tuning charge transport properties of single nanocluster with atomically precise structure, including precious metal nanocluster, polyoxometalates, and fullerenes. On this basis, we will systematically study the structure-effect relationship between the charge transport properties of individual nanoclusters and their size, morphology, composition, and other factors, Then, investigate the general rule and control methods of charge transport through single nanoclusters. The focus of this project is to put forward models of single-cluster electronics with novel quantum effects and provide an important research basis for the extension of single-molecule electronics to single cluster electronics.

理解纳米乃至亚纳米尺度下单个纳米团簇的电输运规律对揭示团簇材料新奇的物理和化学性质具有重要意义，也正成为国际上团簇化学和物理化学交叉研究的重要前沿。纳米材料的电学性质对待测样品的物质组成、几何结构、电子结构以及周围环境均非常敏感。因此，研究单个纳米团簇的电输运性质不仅有助于我们认识这种重要的过渡态物质结构所具有的基本特性，并且能够拓展单团簇在电子学领域的应用。本项目希望通过设计和搭建电化学门控-机械可控裂结装置，以贵金属纳米团簇、多酸纳米团簇和富勒烯团簇为研究对象，实现具有原子级精确结构的单个纳米团簇电输运性质的精确测量和调控。在此基础上，系统性地研究单个纳米团簇的电输运性质与其尺寸、形貌、组成等因素之间的构效关系，探索单个纳米团簇电输运行为的一般规律和调控方法。旨在模拟提出具有新型量子效应的单团簇电子学器件，并为单分子电子学拓展到单团簇电子学提供重要的研究基础。

基于量子隧穿的纳米电子器件为5 nm以下的电子器件小型化提供了一条有效途径。金属纳米团簇作为重要的过渡态物质，具有精确可控的几何结构和电子结构，二者与团簇的电学性质密切相关。研究金属纳米团簇的电输运规律并理解团簇结构和电输运性质之间的构-效关系，对未来设计和构筑具有新型量子效应的单团簇电子器件具有重要意义。本项目研究小组对自主搭建的机械可控裂结装置进行优化升级，实现了单个纳米团簇结的稳定构筑和电学性质表征；系统探究了纳米银团簇的电输运性质，归纳了纳米银团簇结的电导随尺寸增大而增大的重要变化规律，讨论了纳米银团簇电输运性质与其结构之间的构-效关系；结合理论计算揭示了纳米银团簇的电输运机制为相干隧穿，并解释了团簇电导随尺寸的变化规律是由最高已占据轨道和最低未占据轨道之间的能隙和团簇-电极间的耦合强度共同作用的结果。该工作为理解金属纳米团簇的电子输运性质提供了新的见解，为未来设计和制备金属纳米团簇电子器件的研究工作奠定了基础。此外，我们从纳米银团簇表面配体分子出发，首次在实验上证明了相邻的非共轭分子之间存在σ-σ堆积作用，能够提供有效的电子输运途径，并且具有与π-π堆积作用相当的电输运能力。该工作为利用非共轭分子制备超分子器件开辟了一条新的途径，增加了纳米器件材料结构的多样性。项目执行期间发表论文4篇，其中项目负责人以第一作者发表论文2篇（Nature Chemistry和Journal of the American Chemical Society各一篇）。