Collaborative Research: Elucidating Exciton Transport in Hierarchical Organic Materials through Time-Resolved Electronic and Vibrational Spectroscopy/Microscopy

合作研究：通过时间分辨电子和振动光谱/显微镜阐明多级有机材料中的激子传输

• 批准号: 2401851
• 负责人: Jean Hubert Olivier
• 金额: $ 28万
• 依托单位: University of New Mexico
• 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: 2023-12-01 至 2025-10-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2401851&HistoricalAwards=false
• 关键词: Collaborative; Research; Elucidating; Exciton; Transport

With support from the Chemical Structure, Dynamics, and Mechanisms-A (CSDM-A) Program in the Division of Chemistry, a research team led by Erik Grumstrup at Montana State University (MSU) and Jean-Hubert Olivier at the University of Miami (UM) is investigating energy transport in light-harvesting superstructures. These organic platforms are comprised of aromatic dyes, stacked in a face-to-face conformation and then covalently “stapled” together with molecular tethers. The structural rigidity conferred by the tethers enables the construction of nanoscale objects that are structurally and electronically well-defined. By varying the physical rigidity of the tethers through synthetic chemistry, the researchers aim to show that energy transport is enhanced when the vibrations between individual molecules are reduced. To study this effect, the research team will use a variety of time-resolved spectroscopies and microscopies that allow direct imaging of energy transport through the nanostructures in the solid state. The overall scientific goal of this work is to provide a fundamental understanding of the level of disorder that can be tolerated in organic materials while still achieving long-range energy transport necessary for applications in catalysis and energy conversion. To broaden the impact of the work, the research team will develop a science communication channel on YouTube that is thematically centered on the role of chemistry in addressing contemporary problems in climate and energy and will leverage these materials to develop a co-hosted general audience seminar series at UM and MSU.Exciton diffusion lengths in organic nanostructures are often measured in the 10s of nanometers, rather than the micron length scale of inorganic semiconductors. Only a few examples of long-range exciton transport have been reported for organic materials, however these demonstrations are serendipitous, and to date, a fundamental understanding of the relevant structure-function relationships that ensure long range exciton transport is lacking. This project leverages a class of covalently tethered molecular assemblies that feature synthetic “knobs” to regulate both dynamic (electron-phonon coupling) and static heterogeneity (length of tethered dye assemblies) without changing the molecular core through which excitons are transported. Exciton transport in a series of increasingly rigidified assemblies will be measured using a variety of ultrafast spectroscopies and microscopies, both in solution and in the solid state. Experimental data from both solution and solid-state spectroscopic studies will be compared to structurally-accurate kinetic Monte Carlo models, which will be utilized to extract fundamental constraints on the structural and electronic parameters that engender long range exciton transport. Results from these combined studies will deliver new fundamental insight into: 1) how excited state properties of solvated assemblies, such as exciton delocalization and diffusion, can be tailored by tuning interchromophore rigidity, and 2) how exciton transport properties are parameterized by structural domain heterogeneity in hierarchical superstructures.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 A (CSDM-A) 项目的支持下，由蒙大拿州立大学 (MSU) 的 Erik Grumstrup 和迈阿密大学的 Jean-Hubert Olivier 领导的研究小组 ( UM）正在研究光捕获上层结构中的能量传输，这些有机平台由芳香族染料组成，以面对面的构象堆叠，然后与分子共价“钉合”在一起。系绳赋予的结构刚性使得能够构建结构和电子上明确的纳米级物体，通过合成化学改变系绳的物理刚性，研究人员旨在证明当之间的振动时能量传输得到增强。为了研究这种效应，研究小组将使用各种时间分辨光谱和显微镜，对固态纳米结构中的能量传输进行直接成像。这项工作的科学目标是提供对有机材料可以容忍的无序程度的基本了解，同时仍然实现催化和能量转换应用所需的长距离能量传输。团队将在 YouTube 上开发一个科学传播频道，该频道的主题是化学在解决当代气候和能源问题中的作用，并将利用这些材料在 UM 和 MSU 共同主办的普通观众研讨会系列。激子扩散长度经常测量有机纳米结构在十纳米级，而不是无机半导体的微米级长度范围内，仅报道了一些有机材料的长程激子输运的例子，但是这些演示是偶然的，并且迄今为止，对相关结构的基本了解。 - 缺乏确保长距离激子传输的功能关系，该项目利用一类具有合成“旋钮”的共价束缚分子组件来调节动态（电子-声子）。耦合）和静态异质性（系留染料组件的长度），而不改变激子在一系列日益刚性的组件中传输的分子核心，将使用各种超快光谱和显微镜在溶液中和在溶液中进行测量。来自溶液和固态光谱研究的实验数据将与结构精确的动力学蒙特卡罗模型进行比较，该模型将用于提取对固态光谱的基本约束。这些综合研究的结果将为以下方面提供新的基本见解：1）如何通过调节发色团间的刚性来调整溶剂化组件的激发态特性，例如激子离域和扩散，以及2 ）如何通过分层上层结构中的结构域异质性来参数化激子输运特性。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的评估进行评估，被认为值得支持影响审查标准。