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Resolving the Fates of Multiple Triplet Excitons in Single Multi-Chromophoric Conjugated Organic molecules

解决单个多发色团共轭有机分子中多个三重态激子的命运

基本信息

批准号：
1904943
负责人：
Terefe Habteyes
金额：
$ 30.33万
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：
2019
资助国家：
美国
起止时间：
2019-08-01 至 2022-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1904943&HistoricalAwards=false
关键词：
Resolving Fates Multiple Triplet Excitons

项目摘要

Organic polymers are long chains of repeating molecular subunits. When they absorb light, some segments of the chain are placed in excited energy states that live for about a billionth of a second. However, a fraction of this energy can become trapped in lower energy states that last much longer, perhaps a thousand times longer. These longer-lived states can interact with each other, as well as excess charges existing on the chain, which poses significant challenges for using polymers in emerging technologies, such as light-emitting diodes and solar energy conversion devices. With support from the Macromolecular, Supramolecular, and Nanochemistry Program in the Division of Chemistry, Professor John Grey at University of New Mexico is studying these long-lived states over a broad range of time scales. Working with his students, Professor Grey is using microscopy methods that can observe single polymer chains to determine how the chain structure and packing influence these long-lived excitations. Their discoveries could inform the design of new polymers. In addition, Professor Grey, who is a veteran himself, is engaging with student veteran groups at the University of New Mexico to increase participation of veteran and non-traditional students in STEM fields though weekly 'lunch and learn' and tutoring sessions. The long-term goal is to improve enrollment and retention of student veterans by recognizing their unique experience and engaging them as leaders in classroom and laboratory settings.The project examines the population dynamics of spin-forbidden (triplet) excited states in multi-chromophoric conjugated polymers and molecular light harvesting arrays. Hybrid single molecule spectroscopy techniques and stochastic kinetic modeling are the primary physical probes used to resolve interactions between multiple triplets spanning time scales from approximately 1 ns up to steady-state conditions. The goal is to be able to count the number of triplets on a single molecule at any given time, and to resolve how these states and their interactions with other excited states evolve with increasing structural (morphological) complexity. This project also exposes new kinetic insights of bimolecular annihilation processes that are often difficult to measure reliably at the bulk material level. The research further utilizes collaborations with synthetic materials chemists to investigate how fine tuning of molecular structure impacts population dynamics of multiple interacting excited states. Student participants gain valuable skills in physical and materials chemistry as well as theoretical modeling vital for the advancement of National science and technology interests.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.

有机聚合物是由重复的分子亚基组成的长链。当它们吸收光时，链的某些部分处于激发态，寿命约为十亿分之一秒。然而，这种能量的一小部分可能会被困在持续时间更长的低能态中，也许是一千倍。这些更长寿命的状态可以相互作用，以及链上存在的过量电荷，这对在新兴技术中使用聚合物提出了重大挑战，例如发光二极管和太阳能转换设备。在化学系大分子，超分子和纳米化学项目的支持下，新墨西哥州大学的John Grey教授正在研究这些长寿命状态在广泛的时间尺度上。格雷教授和他的学生们一起工作，使用显微镜方法可以观察单个聚合物链，以确定链结构和包装如何影响这些长寿命的激发。他们的发现可以为新聚合物的设计提供信息。此外，格雷教授，谁是一个老兵自己，是在新墨西哥州的大学与学生退伍军人团体参与，以增加退伍军人和非传统的学生在干领域的参与，通过每周的“午餐和学习”和辅导课程。长期目标是通过认可学生退伍军人的独特经验并让他们成为课堂和实验室环境中的领导者来提高他们的入学率和保留率。该项目研究了多发色团共轭聚合物和分子捕光阵列中自旋禁戒（三重态）激发态的种群动力学。混合单分子光谱技术和随机动力学建模是用于解决多个三联体之间的相互作用的主要物理探针，跨越时间尺度从约1 ns到稳态条件。目标是能够在任何给定时间计算单个分子上的三重态的数量，并解决这些状态及其与其他激发态的相互作用如何随着结构（形态）复杂性的增加而演变。该项目还揭示了双分子湮灭过程的新动力学见解，这些过程通常难以在散装材料水平上可靠地测量。该研究进一步利用与合成材料化学家的合作，研究分子结构的微调如何影响多个相互作用激发态的种群动力学。学生参与者在物理和材料化学以及理论建模方面获得宝贵的技能，这对国家科学和技术利益的发展至关重要。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影响审查标准进行评估，被认为是值得支持的。