Point of Anchor: Impacts on Interfacial Charge Transfer of Semiconductor Nanoparticles

加州大学圣克鲁兹分校的陈少伟教授在化学系大分子、超分子和纳米化学项目的支持下，开发了新的化学键模式，以稳定具有有机保护层的半导体纳米颗粒。半导体纳米颗粒是一种独特的功能材料家族，已经发现了多种实际应用。半导体的导电性介于导体（如金属铜）和绝缘体（如玻璃）之间。半导体用于激光二极管、太阳能电池、电子电路等。本研究项目旨在合理选择与半导体纳米颗粒表面的化学连接，以调整其光学和电子特性，并增强其在光电器件，传感器和其他实际应用中的应用。特别是，该项目的重点是提高纳米粒子的光催化活性，利用光能进行有效的化学转化为特定的产品。研究生接受先进的多学科研究方法的培训。此外，研究活动与一些教育和推广计划密切结合，以激励少数民族，妇女，弱势本科生和当地合格的高中学生。这些研究经历为这些学生未来在STEM领域的职业生涯做好了准备。半导体纳米颗粒代表了一类独特的功能纳米材料，已经发现了不同的应用，如催化、光电子、（生物）成像和（生物）诊断。类似于它们的金属对应物，半导体纳米颗粒通常功能化与选择的有机盖配体，从小分子到金属配合物和聚合物基质。在早期的研究中，半导体纳米粒子与配体的相互作用多为非共轭键，这严重阻碍了纳米粒子核心与盖层配体功能部分之间的电子耦合，因此需要大量的能量来诱导电荷在界面上转移。这种屏障可以通过共轭核配体界面键有效地减弱。因此，本研究项目的中心目标有三个方面：为半导体纳米颗粒的表面功能化开发新的界面化学，检查界面键相互作用（共轭与非共轭）对纳米颗粒光学和电子特性的影响，并利用这些独特的材料特性来增强材料在光催化中的应用。通过理论和实验研究的结合，本研究可以丰富半导体纳米颗粒表面功能化的工具箱，这是增强应用的重要基础框架。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Professor Shaowei Chen of the University of California-Santa Cruz is supported by the Macromolecular, Supramolecular, and Nanochemistry Program of the Division of Chemistry to develop new chemical bonding patterns to stabilize semiconductor nanoparticles with an organic protective layer. Semiconductor nanoparticles are a unique family of functional materials that have found diverse practical applications. A semiconductor has an electrical conductivity between that of a conductor, such as metallic copper, and an insulator, such as glass. Semiconductors are used in laser diodes, solar cells, electronic circuits, etc. This research projects seeks to judicially select the chemical linkage to the surface of the semiconductor nanoparticles so as to tune their optical and electronic properties and enhance their use in optoelectronic devices, sensors and other practical applications. In particular, the focus of this project is to enhance the photocatalytic activity of the nanoparticles in the use of light energy for efficient chemical conversions to specific products. Graduate students are trained in advanced multidisciplinary research methods. In addition, research activities are closely integrated with several educational and outreach programs to motivate minority, women, disadvantaged undergraduate students and qualified high-school students from the local area. The research experience prepares these students for future careers in STEM areas. Semiconductor nanoparticles represent a unique class of functional nanomaterials that have found diverse applications, such as catalysis, optoelectronics, (bio)imaging, and (bio)diagnosis. Analogous to their metallic counterparts, semiconductor nanoparticles are generally functionalized with select organic capping ligands, ranging from small molecules to metal complexes and to polymeric matrices. In earlier studies, the semiconductor nanoparticle-ligand interactions mostly involved nonconjugated linkages, which significantly impeded the electronic coupling between the nanoparticle core and functional moieties of the capping ligands, so that a large amount of energy was needed to induce charge transfer across the interface. Such a barrier can be efficiently diminished with a conjugated core-ligand interfacial linkage. Thus, the central goal of the present research project is three-fold: to develop new interfacial chemistry for the surface functionalization of semiconductor nanoparticles, to examine the impacts of interfacial bonding interactions (conjugated vs. nonconjugated) on the nanoparticle optical and electronic properties, and to exploit these unique materials properties to enhance the materials applications in photocatalysis. Through a deliberate combination of theoretical and experimental studies, this research may enrich the toolbox of semiconductor nanoparticle surface functionalization, an important fundamental framework for enhanced applications.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.