基于双笼氟代富勒烯体系的功能分子器件的构造及其传输机制研究

The great electron affinity can be achieved on the center of fullerene cage by the join of fluorine atoms which have high electronegativities, and it makes fluorinated fullerenes are able to encapsulate an excess electron in the cage to form solvated electron system. Then a series of conductive materials with unique optical, electrical and magnetic properties can be built based on fluorinated fullerenes, and have huge potential application value in the field of functional molecular devices. In this project, based on these interests as well as the unique characteristics of single fullerene molecule junctions, a series of molecular devices will be built with the different double-cage fluorinated fullerenes as the central molecules and different electrode materials such as gold or carbon nanotube or graphene. The electron transport properties of these devices will be investigated with theoretical techniques in which density functional theory coupled with the nonequilibrium Green’s function formalism. The goal of the project is to understanding the transport mechanism of these molecular devices, and to achieve some devices with specific electrical behaviors. The results of the project will help people to clear the electronic transport mechanism of the molecular devices based on double-cage fluorinated fullerenes, and show some light on the application in molecular electronics of them.

具有强电负性的氟原子的加入使得氟代富勒烯碳笼中心具有很大的电子亲合势，能够禁锢额外注入的电子，形成溶剂化电子体系，从而可以制备具有独特光、电、磁等性质的传导材料，因此在功能分子器件领域有着巨大的潜在应用价值。本项目拟采用密度泛函理论和非平衡格林函数相结合的第一性原理计算方法，选取一系列双笼氟代富勒烯作为中心分子，以不同金属和碳基材料作为电极，构建一系列的分子电子器件，系统研究其电子输运行为，重点考察碳笼尺寸、桥联基团、门电压、以及中心分子与电极之间的相互作用对器件输运性质的影响，从电子结构的角度揭示其输运本质；通过分子设计和器件设计的方法调节中心分子的电子结构和电子分布，调控体系对额外电子的束缚和转移行为，以实现具有特定电学行为的分子器件。相关研究结果将有助于理解基于双笼氟代富勒烯分子体系分子器件的电子输运机理，为其在分子电子学中的应用提供基础理论依据。

本项目以C20F18(X)2C20F18(X=NH,CO,BH)双笼氟代富勒烯为中心分子，不同金属和碳基材料为电极，构建了一系列的分子电子器件，采用密度泛函理论和非平衡格林函数相结合的第一性原理计算方法，对其电子输运性能进行了计算。探讨了其输运机理，考察了桥联基团、电极和门电压对器件输运性质的影响，明确了调控该类型分子电子器件输运性能的有效手段。相关研究结果将有助于理解基于双笼氟代富勒烯分子体系分子器件的电子输运机理，为其在分子电子学中的应用提供基础理论依据。