Exciton Dissociation Dynamics at Organic-Organic and Organic-Inorganic Semiconductor Heterojunctions

有机-有机和有机-无机半导体异质结的激子解离动力学

• 批准号: 0804583
• 负责人: Xiaoyang Zhu
• 金额: $ 45.19万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-01 至 2009-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0804583&HistoricalAwards=false
• 关键词: Exciton; Dissociation; Dynamics; Organic; Inorganic

Technical: This project aims to investigate fundamental mechanisms governing exciton dissociation at organic-organic or organic-inorganic hybrid semiconductor interfaces. These include energetic driving force, electronic coupling strength, and nuclear reorganization energy in interfacial electron transfer, the potential roles of geminate pair formation, and charge-recombination as competing dynamic channels. Femtosecond time-resolved two-photon photoemission spectroscopy (TR-2PPE) will be used to probe exciton dissociation dynamics at well-ordered organic-organic or organic-inorganic interfaces. The use of single crystal substrates and highly ordered crystalline thin films minimizes heterogeneity problems in nanostructured materials; examples of model systems include oligothiophene and pentacene on single crystal C60 and ZnO surfaces. A TR-2PPE experiment will allow one to directly follow the electron in time, energy, and momentum spaces as it is excited in the form of an exciton in the donor material, as it is en route to the acceptor, as it forms a geminate pair across the donor/acceptor interface, and as it relaxes in the acceptor. The long-term objective is to establish fundamental principles and design rules for exciton dissociation and charge separation at organic heterojunctions for solar cells.Non-technical: The project addresses basic research issues in a topical area of materials science with high technological relevance, and is expected to fill an important knowledge gap in the development of organic solar cells. Developing solar energy technologies that are economically competitive is one of the most important scientific and technological challenges in this century. From an educational perspective, the project will provide an inspiring opportunity for participating students to work on scientifically challenging and socially responsible research. The PI has established a track record and will continue not only in educating graduate students, but also in motivating and involving undergraduates and high school students in research. The PI will also develop a freshman seminar course which focuses on solar energy and the environment challenges.

技术：该项目旨在研究有机有机或有机无机混合式半导体界面上控制激子解离的基本机制。这些包括能量驱动力，电子耦合强度和界面电子传递中的核重组能，颗粒对形成的潜在作用以及电荷重组作为竞争动态通道。飞秒时间分辨的两光子光发射光谱（TR-2PPE）将用于探测良好的有机有机或有机无机界面上的激子解离动力学。单晶基材和高度有序的结晶薄膜的使用最小化纳米结构材料中的异质性问题。模型系统的示例包括单晶C60和ZnO表面上的寡硫苯和五苯。一个TR-2PPE实验将允许一个人以时间，能量和动量空间直接跟随电子，因为它以供体材料中的激子的形式激发，因为它是在接受者的途中，因为它在供体/受体界面上形成了双子座对，并且在受体中放松。长期目标是建立对激子解离的基本原理和设计规则，并在太阳能电池的有机异质界分离。Non-Technical：该项目解决具有高技术相关性材料科学领域的基础研究问题，并且有望填补有机太阳能电池开发的重要知识差距。开发具有经济竞争性的太阳能技术是本世纪最重要的科学和技术挑战之一。从教育的角度来看，该项目将为参与学生提供一个鼓舞人心的机会，从事科学挑战和对社会负责的研究。 PI已经建立了往绩，不仅将继续教育研究生，还将继续激励和涉及本科生和高中生研究。 PI还将开发一个新生研讨会课程，该课程的重点是太阳能和环境挑战。