CAS: Harvesting Electrons From Lower Energy Excited States to Extend Spectral Coverage and Facilitate Multiple Charge Collection Following Singlet Fission on Metal Oxides

CAS：从较低能量激发态收集电子以扩展光谱覆盖范围并促进金属氧化物上单线态裂变后的多重电荷收集

• 批准号: 2247164
• 负责人: David Blank
• 金额: $ 20万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2247164&HistoricalAwards=false
• 关键词: CAS; Harvesting; Electrons; Lower; Energy

With support from the Chemical Structure, Dynamics & Mechanisms-B Program of the Chemistry Division, Professors Blank and Gladfelter from the University of Minnesota-Twin Cities and Professor Pappenfus from the University of Minnesota-Morris seek to build a more thorough understanding of how light can be used to induce separation of charge, a critical first step in the conversion solar energy into electrical or chemical energy. In addition to photovoltaic devices, light-induced charge transfer is part of other devices such as sensors. This project will focus on using well-defined nanocrystals of metal oxides as the scaffold for probing this behavior. A better understanding of how to leverage metal oxide semiconductors is expected to contribute to the development of a range of optoelectronic devices and to improving the efficiency of such devices. This project will directly support the training and education of the next generation of physical/physical organic chemists, including graduate students and undergraduate students, in areas of chemistry that cross the traditional disciplinary boundaries. The University of Minnesota-Morris is a rural, primarily undergraduate institution, and this project will provide undergraduate students at Morris with a collaborative research experience.Nanocrystalline films of semiconducting metal oxides often play a central role in devices that involve the separation of charge. Commonly employed metal oxides have conduction band energies that place thermodynamic and kinetic limitations on the molecules used as sensitizers. Indium oxide has yet to receive much attention, but it has tremendous potential. With a lower energy conduction band, it opens a new window of opportunity to access lower energy sensitizer states. This window would, in principle, allow extension of the spectrum of light that can be harvested and provide access for charge transfer from lower energy triplet states of the sensitizers. The triplet states that are of particular interest in this proposal are those that are generated via singlet fission. This project will use transparent solution phase dispersions of nanocrystals with narrow size distributions as a well-defined experimental platform to investigate the excited state dynamics and charge transfer of the sensitizer. The goal is to realize, characterize and optimize charge multiplication through singlet fission on a transparent metal oxide surface with the potential to increase the efficiency of light harvesting.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.

在化学系化学结构、动力学和机理b项目的支持下，明尼苏达大学双城分校的布兰克教授和格拉德费尔特教授以及明尼苏达大学莫里斯分校的帕彭弗斯教授试图更透彻地了解如何利用光诱导电荷分离，这是将太阳能转化为电能或化学能的关键第一步。除了光伏器件外，光致电荷转移也是传感器等其他器件的一部分。该项目将重点使用定义良好的金属氧化物纳米晶体作为探测这种行为的支架。更好地理解如何利用金属氧化物半导体有望有助于一系列光电器件的发展，并提高这些器件的效率。该项目将直接支持下一代物理/物理有机化学家的培训和教育，包括研究生和本科生，跨越传统学科界限的化学领域。明尼苏达大学莫里斯分校是一所以本科生为主的农村院校，该项目将为莫里斯大学的本科生提供合作研究经验。半导体金属氧化物的纳米晶薄膜通常在涉及电荷分离的器件中起着核心作用。通常使用的金属氧化物具有导带能量，这对用作敏化剂的分子施加了热力学和动力学限制。氧化铟目前还没有得到足够的重视，但它具有巨大的潜力。具有较低的能量传导带，它打开了一个新的机会窗口，以获得较低的能量敏化状态。原则上，这个窗口将允许扩展可以收获的光谱，并为敏化剂的低能量三重态的电荷转移提供通道。在这个提议中特别有趣的三重态是那些通过单线态裂变产生的。本项目将使用具有窄尺寸分布的纳米晶体的透明溶液相分散体作为明确定义的实验平台，研究敏化剂的激发态动力学和电荷转移。目标是通过透明金属氧化物表面的单线态裂变实现、表征和优化电荷倍增，并有可能提高光收集的效率。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。