Microscopy of Functional Molecules

有机电子材料是富含碳的化合物，其组成和结构可优化特定的功能特性，如电荷迁移率、光导性或发光/磷光。由于有机材料的制造和加工成本低，并且它们可以沉积在低成本（柔性）衬底上，因此有机薄膜现在是许多商业产品的重要组成部分，最引人注目的是已经出现在手机和平板电脑上的高效，明亮和彩色显示器。此外，利用该技术开发稳定的薄膜晶体管和低成本发电的光伏器件也有重要的研究工作。尽管最近有机薄膜电子学在商业上取得了成功，但在分子电子学的全部潜力得以实现之前，仍有巨大的挑战有待解决。为了实现在电子设备或器件中使用廉价、原子精确分子的愿景，需要测量和控制嵌入在固态设备或传感器中的分子的功能特性的新方法。这是因为单分子器件的性能关键取决于分子结构的每一个细节，包括与固态载体的接触。在过去的五年中，扫描探针的能力有了显著的提高，这对表面分子的研究具有重要的意义。这些能力包括：以亚分子分辨率测量分子的电致发光，清楚地分辨碳原子之间的单个共价键，区分共价键的键序，探测单个分子内的电荷分布。其中一些进步依赖于用“探针”粒子（CO或Xe）制造原子精度尖端的能力。另一些则依赖于石英悬臂梁（qPlus传感器）提供的稳定性。*******在本提案中，我们试图通过利用这些新功能来解决基于分子的电子学的重大挑战。我们的长期目标是在原子水平上控制有机-无机界面。为了实现这一目标，我们将测量和操纵表面分子的功能特性，并研究一种利用n-杂环碳烯将分子附着在金属表面的新方法。该研究项目具有国际性、多学科性和合作性。它包括化学家，他们将合成分子，三个理论小组，他们将进行第一性原理计算，三个实验小组，他们拥有与我在女王大学的小组互补的专业知识。加拿大研究生将与理论家密切合作，并前往我们的实验合作者，利用扫描探针显微镜在低温（1 K），高磁场（8 T）和光探测下工作

Organic electronic materials are carbon-rich compounds with a composition and structure that is tailored to optimize a particular functional property such as charge mobility, photoconductivity or luminescence/phosphorescence. Because the manufacturing and processing costs of organic materials are low, and they can be deposited on low cost (flexible) substrates, organic thin films are now important parts of many commercial products, the most notable being the high efficiency, bright and colorful displays that have appeared on mobile phones and tablets. There is also significant research effort to develop stable thin-film transistors and photovoltaic devices for low cost energy generation with this technology.*** ***Despite the recent commercial success of organic thin-film electronics, grand challenges remain to be solved before the full potential of molecule-based electronics can be realized. To fulfill this vision of using inexpensive, atomically precise molecules in electronic devices or as devices, new ways of measuring and controlling the functional properties of molecules embedded in a solid state device or sensor are required. This is because the properties of single molecule devices depend, crucially, on every detail of the molecule's configuration, including the contact to the solid state host. ***    ***In the last five years, there have been dramatic improvements in the capabilities of scanning probes that have important implications for the study of molecules at surfaces. These include the ability to: measure electroluminescence from molecules with sub-molecular resolution, clearly resolve single covalent bonds between carbon atoms, discriminate the bond order of covalent bonds, and probe the charge distribution within single molecules. Some of these advances depend upon the ability to create atomically precise tips with 'probe' particles (CO or Xe). Others depend on the stability afforded by quartz cantilevers (qPlus sensors).*******In this proposal, we seek to address the grand challenges of molecule-based electronics by exploiting these new capabilities. Our long term goal is atomic-level control of the organic-inorganic interface. As a step towards this, we will measure and manipulate the functional properties of molecules at surfaces and investigate a new way of attaching molecules to metal surfaces using n-heterocyclic carbenes.  The research program is international, multidisciplinary and collaborative. It involves Chemists, who will synthesize molecules, three theoretical groups, who will perform first principles calculations, and three experimental groups, who possess complementary expertise to my group at Queen's. Canadian graduate students will work closely with theorists and travel to our experimental collaborators to take advantage of scanning probe microscopes that operate at low temperature (1 K), at high magnetic field (8 T) and with light detection.**