Photoinduced Charge Transfer at Quantum Dot-Molecule-Semiconductor Interfaces

布法罗大学（UB）的大卫·沃森（David Watson）获得了大分子、超分子和纳米化学项目的奖励，研究量子点(QD)-分子-半导体界面的光诱导电荷转移过程。该研究涉及基础科学，将量子点连接到半导体衬底或通过小分子相互连接，并使用时间分辨光谱和光电化学表征在所得界面上的电荷转移。一项研究计划涉及阐明界面化学和性质对qd -分子- tio2界面上电荷转移的机制、动力学和产率的影响。具体目标是提高界面的稳定性和惰性，同时保持高电荷转移产率和促进长寿命的电荷分离，测量复杂界面上的电荷转移动力学，并设计界面特性以促进量子点和TiO2之间的长距离电荷转移。第二个研究计划涉及通过碳二亚胺化学将量子点共价拴住，并探索由此产生的组装的光诱导电荷转移反应性。目的是建立促进光生电荷分离的ii型界面的合成方法。第三项研究计划涉及将量子点-分子-量子点组装系在接受电子或空穴的半导体衬底上，以促进光致矢量电荷转移。半导体量子点具有独特的尺寸依赖的电子和光学特性，这使它们成为有趣的光收集器和高能电子和太阳能转换空穴的供体。基于量子点的太阳能电池和光催化剂需要(1)控制量子点在纳米结构表面上的位置，(2)存在一种机制，通过这种机制，光生成的电子或空穴可以在重组之前从量子点中提取出来。本研究项目涉及基础科学，以建立稳定和惰性含量子点界面的合成，并发现这些界面的结构和性质如何控制电荷转移反应的速率和效率。该研究解决了材料化学中的两个基本挑战：(1)精确地组装材料界面；(2)在复杂界面上建立涉及电荷转移的结构-性能-反应性关系。该奖项支持布法罗大学的研究人员与布法罗公立学校的学生和教师之间的合作。拓展活动包括指导高中学生和教师动手研究项目。目标是向参与者介绍科学研究的本质，增加教师内容知识，并发展扩展的指导网络。研究和教育倡议的目的是通过提供与太阳能转换有关的新的基本知识，同时扩大代表性不足的群体的参与，促进发现和理解，从而造福社会。

David Watson at the University at Buffalo (UB) is supported by an award from the Macromolecular, Supramolecular and Nanochemistry program to study photoinduced charge-transfer processes at quantum dot (QD)-molecule-semiconductor interfaces. The research involves basic science to tether QDs to semiconductor substrates or to each other via small molecules, and to characterize charge transfer at the resulting interfaces using time-resolved spectroscopy and photoelectrochemistry. One research initiative involves elucidating the influence of interfacial chemistry and properties on the mechanisms, dynamics, and yields of charge transfer at QD-molecule-TiO2 interfaces. Specific aims are to increase the stability and inertness of interfaces while maintaining high charge-transfer yields and promoting long-lived charge separation, to measure charge-transfer dynamics at complex interfaces, and to engineer interfacial properties to promote long-distance charge-transfer between QDs and TiO2. A second research initiative involves covalently tethering QDs to each other via carbodiimide chemistry and exploring the photoinduced charge-transfer reactivity of the resulting assemblies. Goals are to establish synthetic methods and to synthesize Type-II interfaces that promote the separation of photogenerated charges. A third research initiative involves tethering QD-molecule-QD assemblies to electron- or hole-accepting semiconductor substrates, towards the goal of promoting photoinduced vectorial charge transfer.Semiconductor QDs have unique size-dependent electronic and optical properties, which make them intriguing harvesters of light and donors of energetic electrons and holes for solar energy conversion. QD-based solar cells and photocatalysts require (1) the controlled placement of QDs on nanostructured surfaces and (2) the existence of mechanisms through which photogenerated electrons or holes can be extracted from QDs before recombining. This research project involves basic science to establish syntheses of stable and inert QD-containing interfaces and to discover how the structure and properties of such interfaces govern the rates and efficiencies of charge-transfer reactions. The research addresses two basic challenges in materials chemistry: (1) to assemble materials interfaces precisely and (2) to establish structure-property-reactivity relationships involving charge transfer at complex interfaces. This award supports outreach programs involving collaboration between researchers at UB and students and teachers at Buffalo Public Schools. Outreach activities involve mentoring high school students and teachers in hands-on research projects. Goals are to introduce participants to the nature of scientific research, to increase teacher content knowledge, and to develop expanded mentoring networks. Research and educational initiatives are intended to benefit society by yielding new fundamental knowledge pertaining to solar energy conversion while broadening the participation of underrepresented groups and advancing discovery and understanding.