The Exchange Mechanism and Exciton Migration in Organic Semiconductors

有机半导体中的交换机制和激子迁移

• 批准号: 1708177
• 负责人: Russell Holmes
• 金额: $ 40万
• 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: 2017
• 资助国家: 美国
• 起止时间: 2017-07-01 至 2021-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1708177&HistoricalAwards=false
• 关键词: Exchange; Mechanism; Exciton; Migration; Organic

Nontechnical Abstract:Organic semiconductors remain the focus of a broad range of next generation optical and electronic materials applications. Compared with inorganic semiconductors such as silicon, the molecular variety available for organic semiconductors, thanks to synthetic organic chemistry, offers near limitless potential. When combined with materials science, this rich molecular tapestry suggests availability of extraordinary control over optical and mechanical properties, materials cost, environmental impact, and simplicity of device construction. Efficient transfer of energy in the solid state is one of the fundamental aspects of both light-emitting and light harvesting devices. A better understanding of the relationship between molecular design and the transfer of energy in organic materials enables design of a broad range of more efficient next-generation optical and electronic devices. This research targets one of the energy transfer mechanisms that historically received less attention, a mechanism known as exchange. This mechanism is operative in all molecular systems, and a better understanding of how it contributes to energy transfer in the solid state will open the door to a broad range of new, and more efficient organic electronics. This project includes introducing thousands of third through sixth grade students from disadvantaged socioeconomic backgrounds to the fundamental concept of energy and the basic idea of pursuing a college education in a STEM field.Technical Abstract:The first step in exciton transport is inter-chromophore energy transfer. Historically, simplicity has promoted binary association of emissive materials with an inductive transfer mechanism and non-emissive materials with an exchange mechanism. This distinction has not always been consistent with observation. This research is developing a better understanding of the role of each mechanism. Experimental accessibility has focused previous attention on luminescent systems. Realizing that the high molecular density inherent to devices facilitates exchange, and acknowledging that exchange does not have the same limitations as induction, this work is filling gaps in the understanding of transport in non-luminescent materials. At the same time, this work is elucidating the combined roles of both mechanisms. Employing methodologies to probe exciton diffusion in both luminescent and non-luminescent materials, this work is elucidating ways to exploit combined approaches to transport, quantifying parasitic exciton quenching via annihilation and polaron trapping, and measuring the effects of exciton fission on energy transport. Taken in aggregate, this research is providing a significant contribution to the understanding of exciton transport in organic semiconductors and developing design principles to enhance the next generation of light harvesting and light-emitting devices. The project is simultaneously training multiple graduate students in a wide range of state-of-the-art physical and materials science theory and experimental techniques.

非技术摘要：有机半导体仍然是广泛的下一代光学和电子材料应用的焦点。与硅等无机半导体相比，有机半导体的分子多样性，得益于合成有机化学，提供了近乎无限的潜力。当与材料科学相结合时，这种丰富的分子挂毯表明可以对光学和机械性能、材料成本、环境影响以及设备构造的简单性进行非凡的控制。固态中能量的有效传递是发光和光收集装置的基本方面之一。更好地理解有机材料中分子设计和能量转移之间的关系，可以设计出更高效的下一代光学和电子器件。这项研究针对的是历史上较少受到关注的能量转移机制之一，即所谓的交换机制。这种机制在所有分子系统中都是有效的，更好地理解它如何有助于固态能量转移将为广泛的新的、更有效的有机电子学打开大门。该项目向数千名社会经济背景较差的三年级至六年级学生介绍了能量的基本概念和在STEM领域接受大学教育的基本思想。技术摘要：激子传输的第一步是发色团间的能量转移。历史上，简单性促进了发射材料与感应转移机制和非发射材料与交换机制的二元关联。这种区别并不总是与观察相符。这项研究正在使人们更好地了解每种机制的作用。实验的可及性已经将先前的注意力集中在发光系统上。认识到器件固有的高分子密度有利于交换，并承认交换不具有与诱导相同的限制，这项工作填补了对非发光材料中传输的理解空白。与此同时，这项工作正在阐明这两种机制的综合作用。采用的方法来探测激子扩散发光和非发光材料，这项工作是阐明如何利用组合的方法来运输，量化寄生激子淬灭通过湮灭和极化子捕获，并测量激子裂变对能量传输的影响。总的来说，这项研究为理解有机半导体中的激子传输和开发设计原则以增强下一代光捕获和发光器件做出了重大贡献。该项目同时培训多名研究生，掌握广泛的最先进的物理和材料科学理论和实验技术。

项目成果

Probing Enhanced Exciton Diffusion in a Triplet-Sensitized Organic Photovoltaic Cell

• DOI: 10.1021/acs.jpcc.9b11091
• 发表时间: 2020-02
• 期刊: The Journal of Physical Chemistry C
• 作者: Kaicheng Shi;Ian J. Curtin;Andrew T. Healy;Tao Zhang;Deepesh Rai;D. Blank;R. Holmes

Intrinsic measurements of exciton transport in photovoltaic cells

• DOI: 10.1038/s41467-019-09062-8
• 发表时间: 2019-01
• 期刊: Nature Communications
• 影响因子: 16.6
• 作者: Zhang Tao;Dana B. Dement;V. Ferry;R. Holmes

Formation of aligned periodic patterns during the crystallization of organic semiconductor thin films

• DOI: 10.1038/s41563-019-0379-3
• 发表时间: 2019-07-01
• 期刊: NATURE MATERIALS
• 影响因子: 41.2
• 作者: Bangsund, John S.;Fielitz, Thomas R.;Holmes, Russell J.
• 通讯作者: Holmes, Russell J.

Overcoming the trade-off between exciton dissociation and charge recombination in organic photovoltaic cells

• DOI: 10.1063/1.5045351
• 发表时间: 2018-10
• 期刊: Applied Physics Letters
• 影响因子: 4
• 作者: Zhang Tao;R. Holmes

Ultrafast electron-transfer in a fully conjugated coumarin-ferrocene donor-acceptor dyads

• DOI: 10.1016/j.jorganchem.2019.03.004
• 发表时间: 2019-05
• 期刊: Journal of Organometallic Chemistry
• 影响因子: 2.3
• 作者: A. King;Yuriy V. Zatsikha;Tanner Blessener;Forrest Dalbec;Philip C. Goff;Mathew P. Kayser;D. Blank;Yu. P. Kovtun;V. Nemykin