Control of 2-Dimensional Molecular Self-Organisation: Towards Designed Surfaces

表面的有机分子单层通常构成纳米技术中的中心工作组件，例如传感器、分子电子学、智能涂层、有机太阳能电池、催化剂、医疗设备等。该领域的一个中心挑战是实现在表面受控创建所需的2D分子结构。在此背景下，在过去的十年中，已经见证了一个真实的和显着的步骤变化的“自下而上”的自组织的二维分子组装在表面。通过自组织形成的分子结构的巨大多样性和丰富性现在已经严重地倾向于支持“自下而上”的构建策略，该策略利用纳米精度（自上而下方法无法实现）和高度并行制造（原子/分子操作不可能）的两个强大属性。因此，自下而上的分子组装在表面持有真实的可能性，成为一个主导的合成协议在21世纪世纪纳米技术独特的是，这些分子架构的范围和通用性在二维表面已被直接捕获在纳米尺度通过扫描探针显微镜和先进的表面光谱成像。然而，目前，该领域在很大程度上限于“制造和看到”的方法，并有任何最终控制分子表面组装的参数缺乏了解。举例来说：（1）表面的分子组装显示出高度的多态性行为，并且组装的先验控制实际上是不存在的;（2）很少了解驱动分子识别和组装的许多相互作用的影响和平衡。（分子-分子相互作用，包括分散、定向氢键和强静电和共价相互作用）;（3）表面-分子相互作用的作用在很大程度上是未知的，尽管它们在分子的扩散及其随后的组装中起重要作用;（4），有充分的证据表明自组装的动力学是决定最终结构的主要因素，通常驱动多晶型行为并导致广泛变化的结果，这取决于形成的条件;（5）各种额外的表面现象也影响组装，例如分子之间的化学反应、分子的热活化内部自由度、表面重构和经由配位表面原子的共组装。该项目的主要目标是推进从实验现象报告知识为基础的设计，其中心目标是确定所发挥的作用，热力学，熵，动力学和化学因素在指定的实验条件下，在表面的分子组织。为了应对这一挑战，需要采取双管齐下的方法，即在应用于相同系统的强大成像和光谱工具的同时，进行雄心勃勃和全面的理论开发。这种实验和理论的协同作用对于发展基本的理解是绝对必要的，这将使控制和工程自组装的路线图在表面上被提出，最终将允许人们随意“拨号”所需的结构。四个重要的和定性不同类的组装在表面将被研究：分子自组装;分级自组装;金属有机自组装;和，表面共价组装。

Organic molecular monolayers at surfaces often constitute the central working component in nanotechnologies such as sensors, molecular electronics, smart coatings, organic solar cells, catalysts, medical devices, etc. A central challenge in the field is to achieve controlled creation of desired 2D molecular architectures at surfaces. Within this context, the past decade has witnessed a real and significant step-change in the 'bottom-up' self-organisation of 2D molecular assemblies at surfaces. The enormous variety and abundance of molecular structures formed via self-oeganisation has now critically tipped the argument strongly in favour of a 'bottom-up' construction strategy, which harnesses two powerful attributes of nanometer-precision (inaccessible to top-down methods) and highly parallel fabrication (impossible with atomic/molecular manipulation). Thus, bottom-up molecular assembly at surfaces holds the real possibility of becoming a dominating synthesis protocol in 21st century nanotechnologies Uniquely, the scope and versatility of these molecular architectures at 2D surfaces have been directly captured at the nanoscale via imaging with scanning probe microscopies and advanced surface spectroscopies. At present, however, the field is largely restricted to a 'make and see' approach and there is scarce understanding of any of the parameters that ultimately control molecular surface assembly. For example: (1) molecular assemblies at surfaces show highly polymorphic behaviour, and a priori control of assembly is practically non-existent; (2) little is understood of the influence and balance of the many interactions that drive molecular recognition and assembly (molecule-molecule interactions including dispersion, directional H-bonding and strong electrostatic and covalent interactions); (3) the role of surface-molecule interactions is largely uncharted even though they play a significant role in the diffusion of molecules and their subsequent assembly; (4), there is ample evidence that the kinetics of self-assembly is the major factor in determining the final structure, often driving polymorphic behaviour and leading to widely varied outcomes, depending on the conditions of formation; (5) a gamut of additional surface phenomena also also influence assembly e.g. chemical reactions between molecules, thermally activated internal degrees of freedom of molecules, surface reconstructions and co-assembly via coordinating surface atoms. The main objective of this project is to advance from experimental phenomena-reporting to knowledge-based design, and its central goal is to identify the role played by thermodynamic, entropic, kinetic and chemical factors in dictating molecular organisation at surfaces under given experimental conditions. To address this challenge requires a two-pronged approach in which ambitious and comprehensive theory development is undertaken alongside powerful imaging and spectroscopic tools applied to the same systems. This synergy of experiment and theory is absolutely essential to develop a fundamental understanding, which would enable a roadmap for controlled and engineered self-assembly at surfaces to be proposed that would, ultimately, allow one to 'dial up' a required structure at will. Four important and qualitatively different classes of assembly at surfaces will be studied: Molecular Self-Assembly; Hierarchical Self-Assembly; Metal-Organic Self Assembly; and, on-surface Covalent Assembly.