International Collaborations in Chemistry: Characterization of organically capped Si and group 14 alloy nanoparticle heterojunctions

该奖项由美国研究人员和德国同行在国际化学合作中的化学部高分子、超分子和纳米化学项目颁发，并由国际科学和工程办公室共同资助。获奖者是加州大学戴维斯分校的苏珊·考兹拉里奇教授。太阳能转换等应用在设备架构方面面临着根本性的挑战，限制了效率。半导体纳米粒子(NP)是目前太阳能转换领域的一个活跃研究领域，它具有可调的带隙和潜在的载流子倍增的优点。硅是人们感兴趣的半导体NPs之一；然而，关于电子结构的性质仍然有很大的争论。特别是，表面氧化和界面终止在决定光学带隙和电学性质方面起着重要作用。Si(1-x)Gex纳米粒子的合成允许在不改变纳米粒子大小的情况下系统地调节带隙。此外，关于具有带状电子结构的无机半导体和具有局域电子态的有机半导体之间的可逆电荷传输是否可以自由进行的根本问题尚未得到回答。本项目的目标是研究硅或硅(1-x)Gex合金的无机纳米颗粒与空穴导电有机分子之间的电荷传输。有机分子通过Si-C键共价键合在纳米颗粒表面。深入了解这种p型系统中的电子传输过程与光伏相关。该项目的合成重点在于纳米颗粒的表面功能化。该项目的这一部分是美国合作伙伴项目的主题。纯Si和Si-Ge合金化纳米颗粒具有很强的活性，其合成和表面化学是一个开放的研究领域。该项目的德国部分专注于合成的有机纳米粒子的光电测量。该项目确保指导妇女和少数族裔学生，并确保研究团队参与校园范围和全国范围的活动，如“农业、文学和科学本科生研究人员会员资格”(MUALS)、“研究生教育和教授联盟”(AGEP)、STEM、与国家实验室合作对学生进行联合培训、教学和推广活动。在加州大学戴维斯分校，未被充分代表的本科生(MURPPS计划)和高中生(ACS SEED)被招募参与这项研究。国际交流活动包括两名研究生和三名本科生有机会与科隆大学的同行互动。

This award is made by the Macromolecular, Supramolecular and Nanochemistry program of the Chemistry Division within the International Collaboration in Chemistry between US investigators and their counterparts in Germany and is co-funded by the Office of International Science and Engineering. The recipient is Professor Susan Kauzlarich of the University of the California-Davis. Applications such as solar energy conversion are faced with fundamental challenges in device architecture that limit efficiencies. Semiconductor nanoparticles (NP) are currently an active area of research in solar energy conversion with the benefits of a tunable band gap to potential carrier multiplication. Silicon is one of the semiconductor NPs of interest; however, there is still a great deal of debate concerning the nature of the electronic structure. In particular, the surface oxidation and interface termination play an important role in determining the optical gap and electronic properties. Synthesis of Si(1-x)Gex NPs allows for systematic tuning of the bandgap without changing size of the NP. In addition, the fundamental question concerning whether reversible charge transport between inorganic semiconductors typically exhibiting a band-like electronic structure and organic semiconductors featuring localized electronic states can take place freely is unanswered. The goal of this project is to study charge transport between inorganic nanoparticles of Si or Si(1-x)Gex alloys and hole-conducting organic molecules. The organic molecules are covalently bonded to the nanoparticle surface via Si-C bonds. Gaining insight on the electron transport process in this p-type system is relevant to photovoltaics. The synthesis focus of the project resides on the surface functionalization of the nanoparticles. This component of the project is the theme of the US partner's project. Pure Si and Si-Ge alloyed nanoparticles are very reactive and their synthesis and surface chemistry are opened fields of study. The German component of the project focuses on optoelectronic measurements of the synthesized organo-capped nanoparticles. The project ensures mentoring women and minority students and participation of the research team in campus-wide and nation-wide activities such as "Memberships for Undergraduate Researchers in Agriculture, Letters, and Science" (MURALS), "Alliance for Graduate Education and the Professoriate" (AGEP), STEM, collaboration with National Laboratories for joint training of students, teaching, and outreach activities. At UC Davis, underrepresented undergraduates (MURPPS program) and high school students (ACS SEED) are recruited to participate in this research. International exchange activities include two graduate students and three undergraduates having the opportunity to interact with peers at the University of Cologne.