Achieving Molecular Level Control over the Chemical, Electrochemical, and Electrical Properties of Crystalline Si Surfaces

在这个由化学部的大分子、超分子和纳米化学项目资助的项目中，加州理工学院的内森刘易斯将开发用于硅表面改性的方法，该方法允许控制穿过这种界面的电荷流的方向、程度和化学形式。 该方法是开发和展示基于化学的方法，该方法将允许在Si上沉积金属而不形成金属硅化物;展示利用导电聚合物作为电荷受体而不是金属电催化剂颗粒的化学方法，以适应电荷流动而不形成金属硅化物;并涉及允许基于Si的光导向表面功能化来操纵导电金属颗粒的物理放置的详细方法，从而催化剂可以直接放置在电荷流过界面的地方。 控制界面电荷流的系统的发展将解决在几个至关重要的应用中实际使用Si表面所提出的一些关键障碍。 其他更广泛的影响包括培训研究生和跨学科表面和能源科学的博士后研究人员，在出版物和科学报告以及电视，广播和电子媒体采访中广泛传播研究成果和概念，并通过加州理工学院化学动画项目进行教育推广。硅表面的化学修饰在与硅基电路的接口，开发新型化学传感器，以及从现有的光伏电池获得更高的效率。 这项工作的目标是开发这种表面的结构-功能关系，并证明新的和有益的器件行为，使凭借分子水平控制的化学硅表面。 在拟议的工作中特别感兴趣的是控制与电子导体接触的硅表面，包括金属，导电聚合物和其他电荷受体。

In this project funded by the Macromolecular, Supramolecular and Nanochemistry Program of the Chemistry Division, Nathan Lewis of the California Institute of Technology will develop methods for the modification of Si surfaces that allow for control over the direction, degree of, and chemical form of, charge flow across such interfaces. The approach is to develop and demonstrate chemically based methods that will allow the deposition of metals onto Si without formation of metal silicides; to demonstrate chemical methods to utilize conducting polymers as the charge acceptor, instead of metallic electrocatalyst particles, to accommodate charge flow without metal silicide formation; and to elaborate methods that will allow manipulation of the physical placement of conductive metal particles based on light-directed surface functionalization of Si, so that catalysts can be placed directly where the charges are flowing across interfaces. The development of systems that control interfacial charge flow will address some of the key barriers presented by actual use of Si surfaces in several critically important applications. Other broader impacts involve training graduate students and postodcotral researchers in interdisciplinary surface and energy sciences, broadly disseminating research results and concepts in publications and scientific presentations as well as TV, radio and electronic media interviews, and educational outreach via the Caltech Chemistry Animation Project.Chemical modification of silicon surfaces is important in interfacing with silicon-based circuitry, developing novel chemical sensors, and obtaining higher efficiencies from existing photovoltaic cells, among many applications. The goal of this work is to develop structure-function relationships for such surfaces and to demonstrate new and beneficial device behaviors that are enabled by virtue of having molecular level control over the chemistry the silicon surface. Of specific interest in the proposed work is the control over silicon surfaces in contact with electron conductors, including metals, conducting polymers, and other charge acceptors.