From single-molecule contacts to well-defined molecular ensemble contacts: Influence of intermolecular interactions onto the electronic transport

在这个项目中，我们将研究分子系综结的电子输运性质，在分子系综结中，小分子以平行排列的方式与金属电极接触。在大多数情况下，它们的输运性质不能直接从相同物种的单分子结中推导出来。这种差异的可能原因包括内在性质（分子相互作用）以及外在原因，如分子水平上的接触几何形状的差异。虽然已经开发了几种技术，能够研究通过单个分子的运输，无论是在统计学的方式和在单个分子的基础上，没有真正可靠的，可扩展的，和通用的方法，通过小分子集合的运输的研究确实存在。这种方法的缺乏阻碍了系统的研究，最近吸引了很多兴趣，从理论方面的内在效应。这种兴趣是由小到中等尺寸的分子系综在分子电子学中的高应用潜力所驱动的，因为它们不太容易受到由单个原子排列引起的伪影的影响，作为单分子结具有较低的电阻，但仍然联合收割机结合了非常小的尺寸和丰富的功能性的优点。申请人DM最近开发了用于制造交叉结构中的分子系综接触的新工艺，其结面积范围从大约50 nm X 50 nm到几百平方微米。该技术已成功地应用于形成几个纳米厚度的薄导电和半导电聚合物层的结。我们建议进一步发展交叉技术的应用程序的自组装单分子膜的分子种类，用于分子电子学。

In this project we will study the electronic transport properties of molecular ensemble junctions, in which small molecules are contacted to metal electrodes in a parallel arrangement. In most cases their transport properties cannot straightforwardly be deduced from those of single-molecule junctions of the same species. Possible reasons for this difference include intrinsic properties (molecular interactions) as well as extrinsic reasons, like differences in the contacts geometry on the molecular level. While several techniques have been developed that enable to study the transport through single molecules, both in a statistical manner and on an individual molecular basis, no really reliable, scalable, and versatile method for the study of the transport through small molecular ensembles does exist. This methodological lack hampers systematic studies of the intrinsic effects that have recently attracted much interest from the theoretical side. The interest is driven by the high application potential of small to medium size molecular ensembles in molecular electronics, because they are less prone to artefacts caused by individual atomic arrangements, have lower resistance as single-molecule junctions but still combine the advantages of very small size and rich functionality. The applicant DM recently developed new processes for the fabrication of molecular ensemble contacts in crossbar architecture, with junction areas ranging from approximately 50 nm x 50 nm to several hundred square micrometers. The techniques have been successfully applied for the formation of junctions of thin conducting and semiconducting polymer layers of several nanometer thickness. We propose to further develop the crossbar technique for the application of self-assembled monolayers of molecular species to be used in molecular electronics.