Photoinduced Charge Transfer at Quantum Dot-Molecule-Semiconductor Interfaces

布法罗大学（UB）的大卫沃森获得了大分子，超分子和纳米化学计划的奖项，以研究量子点（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，通过小分子将量子点束缚在半导体衬底上或彼此之间，并使用时间分辨光谱学和光电化学来表征所得界面处的电荷转移。一项研究计划涉及阐明界面化学和性质对QD-分子-TiO 2界面电荷转移的机制、动力学和产率的影响。 具体目标是增加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，测量复杂界面的电荷转移动力学，并设计界面特性，以促进量子点和二氧化钛之间的长距离电荷转移。 第二项研究计划涉及通过碳二亚胺化学将量子点彼此共价连接，并探索所得组装体的光诱导电荷转移反应性。 目标是建立合成方法和合成促进光生电荷分离的II型界面。 第三个研究计划是将量子点-分子-量子点组装体连接到电子或空穴接受的半导体衬底上，以促进光诱导的矢量电荷转移。半导体量子点具有独特的尺寸依赖性电子和光学性质，这使它们成为太阳能转换的光收集器和高能电子和空穴的供体。 基于QD的太阳能电池和光催化剂需要（1）QD在纳米结构表面上的受控放置和（2）存在这样的机制，通过该机制，可以在重新组合之前从QD提取光生电子或空穴。 该研究项目涉及基础科学，以建立稳定和惰性的含QD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）精确组装材料界面和（2）建立涉及复杂界面电荷转移的结构-性能-反应性关系。 该奖项支持涉及UB研究人员与布法罗公立学校学生和教师之间合作的推广计划。 外联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性质，增加教师的内容知识，并发展扩大的指导网络。 研究和教育举措旨在通过产生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.