CAREER: Synthetically Controlled Plasmon-Multiexciton Interaction in Semiconductor-Metal Hybrid Nanostructures

美国国家科学基金会化学系的大分子、超分子和纳米化学(MSN)计划资助康涅狄格大学(UConn)赵静教授开发合成方法，以改善激光应用中基于金属和半导体纳米颗粒的纳米结构的发射性能。当被光激发时，纳米金属和半导体晶体显示出独特的光学性质。通过将这两种类型的粒子组合在一个混合结构中，预计会增加光发射。这种混合纳米材料可以潜在地用于纳米激光器，并在通信系统中用作光子源。正在为本科生和研究生开发新的课程，重点是光学纳米材料及其在许多不同技术中的应用。这项研究还被纳入参加康涅狄格州大学化学暑期研讨会的高中生的外联活动中，在该研讨会上，正在进行金属和半导体纳米晶体的合成和光学表征。在这项研究中，人们正在开发一种新的合成方法来制备一对一的金属-半导体杂化纳米结构，并控制其空间关系。确定了在杂化纳米结构中调制等离子体激子-激子相互作用的几何和光学因素，以便有效地设计和制造杂化材料以满足预期的应用。在单粒子水平上的相关结构-性质方法被用来理解纳米结构的几何结构如何决定它们的等离子体共振和激子/多激子发射效率。本文主要研究了等离子体激子对单个半导体纳米晶多激子发射效率的影响及其与粒子间距、激发条件和纳米结构几何形状的依赖关系。研究内容包括：(I)开发新的合成策略来制备一对一的金属-半导体杂化纳米结构；(Ii)揭示杂化纳米颗粒的几何结构与其在单粒子水平上的光学性质之间的关系；以及(Iii)阐明单一半导体纳米晶体的多激子发射效率的等离子体增强机制。从研究中获得的知识和纳米材料被应用于光电子器件的设计和制造中，以提高其性能。与康涅狄格州大学早期学院体验计划合作，也正在为高中教师和学生开发短期课程和实验室演示。此外，还鼓励女性和代表性不足的少数群体参与研究计划。

The Macromolecular, Supramolecular, and Nanochemistry (MSN) Program in the Division of Chemistry at the NSF is funding Professor Jing Zhao of the University of Connecticut (UCONN) to develop synthetic methods to improve the emitting properties of nanostructures based on metallic and semi-conductor nanoparticles for applications in lasers. When excited by light, nanosized metal and semiconductor crystals exhibit unique optical properties. By combining these two types of particles in one hybrid structure, increased light emission is expected. The hybrid nanomaterials can potentially be used in nanolasers and as the photon source in communication systems. New courses are being developed for undergraduate and graduate students focusing on optical nanomaterials and their applications in many different technologies. The research is also being integrated into outreach activities for high school students participating in a UCONN chemistry summer workshop, where the synthesis and optical characterization of metal and semiconductor nanocrystals are being undertaken. In this research, a novel synthetic method is being developed to fabricate a one-to-one metal-semiconductor hybrid nanostructure with control of its spatial relationship. Geometric and optical factors that modulate the plasmon-exciton interaction in the hybrid nanostructures are identified so that the hybrid materials can be effectively designed and fabricated for desired applications. A correlated structure-property approach at the single particle level is used to understand how the geometry of the nanostructures determines their plasmon resonance and exciton/multiexciton emission efficiencies. This work focuses on the plasmonic effect on the multiexciton emission efficiency of single semiconductor nanocrystals and its dependence on interparticle distance, excitation conditions and geometry of the nanostructures. The research includes: (i) producing new synthetic strategies to fabricate one-to-one, metal-semiconductor hybrid nanostructures; (ii) revealing the relationship between the geometry of the hybrid nanoparticles and their optical properties at a single particle level; and (iii) elucidating the plasmon enhancement mechanism of the multiexciton emission efficiency of single semiconductor nanocrystals. The knowledge and nanomaterials obtained from the research is applied in the design and fabrication of optoelectronic devices to improve their performance. In collaboration with the UCONN Early College Experience program, short courses and laboratory demonstrations for high school teachers and students are also being developed. Moreover, female and underrepresented minorities are encouraged to participate in the research program.