Using conduction spin electron spectroscopy as a sensitive and selective probe for understanding the surface chemical control over the electronic behavior of metallic nanoparticles

化学系的大分子、超分子和纳米化学项目支持宾夕法尼亚州立大学大学公园的本杰明·李尔博士。 Lear博士的项目描述了金属纳米颗粒与其周围环境之间的相互作用。金属纳米颗粒是极小的金属颗粒，其中结构尺寸（长度、宽度或厚度）中的至少一个在纳米尺寸范围（1至100 nm）内。 金属纳米颗粒具有广泛的应用，包括化学制造，电子设计和癌症治疗。 在这些应用中，纳米颗粒表面附近的环境可以是相当多样化的。人们对这些环境变化如何影响纳米颗粒的理想电子特性知之甚少。该项目开发并应用了一种新技术，以了解周围环境对金属纳米颗粒电子特性的影响。这项研究的结果将导致新的先进技术的发展，其中纳米颗粒和周围环境的相互作用得到优化。作为该项目的一部分，Lear博士有多名高中生在他的实验室工作，作为宾夕法尼亚州立大学推广计划的一部分，该计划为来自“风险”学校的学生提供培训。该项目研究了表面化学和化学环境对小（直径约2 nm）金纳米颗粒（AuNP）电子结构的影响。大量的表面化学进行检查，并使用X射线粉末衍射（XRD），透射电子显微镜（TEM），核磁共振（NMR），电化学和传导电子自旋共振（CESR）的纳米粒子的性质进行了研究。CESR提供了一个敏感的和选择性的探针的电子环境所经历的费米能量附近的金属芯。该项目建立了CESR响应表面化学变化的机制。此外，该项目通过探索溶剂，电化学电势和配体变化的影响来探索AuNPs对局部环境变化的敏感性。详细了解金属的电子学和表面化学之间的协同关系对于器件设计和开发的进步至关重要。该项目的资金还支持来自“风险”学校的高中生参与尖端科学，旨在了解表面化学如何影响金属的电子特性。

The Macromolecular, Supramolecular and Nanochemistry Program of the Division of Chemistry supports Dr. Benjamin Lear from the Pennsylvania State University, University Park. Dr. Lear's project characterizes the interactions between metallic nanoparticles and their surrounding environment. Metallic nanoparticles are extremely small particles of metal where at least one of the structural dimensions (length, width or thickness) is in the nanometer size range (1 to 100 nm). Metallic nanoparticles have a wide range of applications including chemical manufacturing, electronics design, and cancer treatment. In these applications, the environment near the nanoparticle surface can be quite diverse. Little is known about how these changes in environment affect the desirable electronic properties of the nanoparticles. This project develops and applies a new technique to understand the effects of the surrounding environment on the electronic properties of metal nanoparticles. The results of this research will lead to the development of new advanced technologies where the nanoparticle and surrounding environment interactions are optimized. As part of this project, Dr. Lear has multiple high school students working in his lab as part of a Pennsylvania State University outreach program that provides training to students from "at risk" schools.This project examines the influence of surface chemistry and chemical environments on the electronic structure of small (diameters of about 2 nm) gold nanoparticles (AuNPs). A large set of surface chemistries are examined, and the properties of the nanoparticles are studied using x-ray powder diffraction (XRD), transmission electron microscopy (TEM), nuclear magnetic resonance (NMR), electrochemistry, and conduction electron spin resonance (CESR). CESR provides a sensitive and selective probe of the electronic environment experienced by electrons near the Fermi energy within the metallic core. This project establishes the mechanism for the CESR response to changes in surface chemistry. Furthermore, this project explores the sensitivity of AuNPs to changes in their local environment by exploring the effects of changes in solvent, electrochemical potential, and ligands. A detailed understanding of the synergistic relationship between the electronics and surface chemistry of metals are critical for advances in device design and development. The project funding also support the involvement of high school students from "at risk" schools in cutting edge science aimed at understanding how surface chemistry affect electronic properties of metals.