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

加州大学圣克鲁斯分校的陈少伟教授在化学系高分子、超分子和纳米化学计划的支持下，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类独特的功能材料，具有广泛的实际应用前景。半导体的导电性介于导体(如金属铜)和绝缘体(如玻璃)之间。半导体被用于激光二极管、太阳能电池、电子电路等。本研究项目旨在合理地选择半导体纳米颗粒表面的化学键，以调节其光学和电学性能，并增强其在光电子器件、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颗粒的光催化活性，利用光能有效地将化学转化为特定产品。研究生接受先进的多学科研究方法培训。此外，研究活动与几个教育和推广方案密切结合，以激励少数民族、妇女、弱势本科生和当地合格的高中生。这些研究经验为这些学生在STEM领域的未来职业生涯做好了准备。半导体纳米粒子代表了一类独特的功能纳米材料，在催化、光电子学、(生物)成像和(生物)诊断等方面有着广泛的应用。与金属纳米粒子类似，半导体纳米粒子通常是由选定的有机封端配体功能化的，从小分子到金属络合物再到聚合物基质。在早期的研究中，半导体纳米粒子-配体之间的相互作用大多涉及非共轭键，这显著阻碍了纳米粒子核心与封顶配体的功能部分之间的电子耦合，因此需要大量的能量来诱导界面上的电荷转移。这样的势垒可以通过共轭的核-配体界面键有效地减小。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，考察界面键合作用(共轭和非共轭)对纳米颗粒光学和电学性质的影响，以及开发这些独特的材料性质以增强材料在光催化中的应用。通过理论和实验研究的精心结合，这项研究可能会丰富半导体纳米粒子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NSF的法定使命，并通过使用基金会的智力优势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.