Photoelectron Emission at Diamond-Liquid Interfaces

技术总结钻石具有一种被称为负电子亲和力(NEA)的不同寻常的性质，这使得它在紫外光照射下可以作为固态电子源。钻石的NEA与其出色的化学稳定性相结合，使其能够用作在非真空条件下运行的固态电子源，甚至能够直接将电子注入液体中。这项拟议的研究由固态和材料化学计划支持，将调查控制水和四氢呋喃等液体中电子发射效率的因素。研究工作将侧重于了解控制电子发射过程的材料因素，确定将以更宽的激发波长谱增加电子发射的条件，并加强NEA的稳定性。有待探索的方法包括掺入磷或氮，以及操纵金刚石-电解液界面的电化学双层。这些测量将为控制非真空条件下光电子发射的效率和稳定性的因素提供基本的新见解。这项研究可以在几个科学技术领域实现新的技术应用，例如改进的场发射显示器，并使液体中的新型化学转化成为可能。该项目将支持对包括本科生和高中生在内的学生进行培训和指导，并努力与州立法者和其他决策者接触，以了解科学研究的社会影响。非技术总结固体材料发出的电子构成了许多现有技术的基础，如计算机显示器。大多数材料需要高温和高真空条件才能发射电子，因此不能在水和其他液体中使用。然而，钻石即使用作廉价的薄膜和/或商业级钻石粉末，在室温下用紫外光照射时也具有向液体发射电子的不同寻常的能力，尽管效率相对较低。这个项目将探索几种不同的方法来提高钻石向液体中发射电子的能力。如果这项工作取得成功，可能会导致计算机显示技术的改进，以及启动重要化学反应的新的、节能的方法，包括将廉价的起始材料转化为更有用的产品，如液体燃料。该项目将支持对包括本科生和高中生在内的学生进行培训和指导，并努力与州立法者和其他决策者接触，以了解科学研究的社会影响。

TECHNICAL SUMMARYDiamond has an unusual property known as negative electron affinity (NEA) that allows it to act as a solid-state source of electrons when illuminated with ultraviolet light. The combination of diamond's NEA with its outstanding chemical stability allows it to be used as a solid-state source of electrons operating under non-vacuum conditions, even able to directly inject electrons into liquids. The proposed research supported by the Solid State and Materials Chemistry Program, will investigate the factors controlling the efficiency of electron emission into liquids such as water and tetrahydrofuran. Research efforts will focus on understanding the materials factors that control the electron emission process and identifying conditions that will increase electron emission with a broader spectrum of excitation wavelengths and on enhancing the stability of NEA. Methods to be explored include doping with phosphorus or nitrogen, and manipulation of the electrochemical double-layer at the diamond-electrolyte interface. These measurements will provide fundamental new insights into factors that control the efficiency and stability of photoelectron emission under non-vacuum conditions. This research could enable new technological applications in several fields of science and technology such as improved field-emitter displays and enable new types of chemical transformations in liquids. The project will support training and mentoring of students, including undergraduates and high school students, and efforts to engage with state legislators and other decision-makers to inform about the societal impact of scientific research. NON-TECHNICAL SUMMARYThe emission of electrons from solid materials underlies many existing technologies such as computer displays. Most materials require high temperature and high vacuum conditions in order to emit electrons and therefore cannot be used in water and other liquids. However, diamond, even when used as inexpensive thin films and/or commercial-grade diamond powder, has the unusual ability to emit electrons into liquids at room temperature when illuminated with ultraviolet light, although with relatively low efficiency. This project will explore several different approaches to improving the ability of diamond to emit electrons into liquids. If this work is successful it could lead to improved computer display technologies and to new, energy-efficienct ways to initiate important chemical reactions, including transformation of inexpensive starting materials into more useful products, such as liquid fuels. The project will support training and mentoring of students, including undergraduates and high school students, and efforts to engage with state legislators and other decision-makers to inform about the societal impact of scientific research.