Engineered Grain Boundaries and their Properties in Crystalline Organic Semiconductors

晶体有机半导体中的工程晶界及其特性

• 批准号: 1205752
• 负责人: Alberto Salleo
• 金额: $ 38万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1205752&HistoricalAwards=false
• 关键词: Engineered; Grain; Boundaries; their; Properties

Technical Description: The goal of this research project is to unravel structure-property relationships at the grain boundaries of crystalline organic semiconductors. Such fundamental understanding is expected to lead to materials or processing techniques that mitigate the effect of grain boundaries. In order to study grain boundaries, engineered microstructures are fabricated using shear-coating or capillary force lithography. These techniques allow to form grain boundaries across which the molecular misorientation can be controlled and characterized accurately using synchrotron-based X-ray diffraction. Charge transport across these well-characterized grain boundaries is studied using field-effect transistors. Furthermore, the presence of trap states in the bandgap of the semiconductor is assessed using ultra-sensitive sub-bandgap spectroscopies. The correlation of transport data and the sub-gap absorption data helps to elucidate the nature of transport bottlenecks across grain boundaries. In addition to transport, the effect of grain-boundary structure on the electronic stability of the semiconductor and the role of polar molecules adsorbed from the atmosphere in tuning the electronic properties of grain boundaries is studied. By conducting these studies as a function of grain-boundary structure, a complete picture of the role of structure in governing the electronic properties of grain boundaries is made to emerge.Non-technical Description: Organic semiconductors are already finding applications as light emitters in the display industry. The versatility of this family of electronic materials, which can be synthesized and functionalized to exhibit a broad range of properties, promises the realization of entire electronic circuits with organic semiconductors as well as solar cells and chemical sensors. Because these materials are held together by weak intermolecular forces however, they suffer from the presence of imperfections or defects. This research project aims at elucidating how defects affect the electronic behavior of organic semiconductors. In particular this project focuses on the boundaries between crystals that form in the film, which often limit the performance of the electronic material. By fabricating model systems, where these boundaries are well controlled, the effect of the structure of these boundaries on electronic properties is revealed. The societal impact of the research is amplified by outreach activities. For instance, remote optical and electronic microscopy, where high-school students are engaged to study materials at the micro and nanoscale, provide a direct link between structure (as observed in the microscope) and properties.

技术描述：该研究项目的目的是在晶体有机半导体的晶界处揭示结构 - 特性关系。这种基本理解有望导致减轻晶界影响的材料或加工技术。为了研究晶界，使用剪切涂层或毛细管光刻制造工程的微观结构。这些技术允许形成晶界，可以使用基于同步加速器的X射线衍射对分子不良的不良反向进行控制和表征。使用现场效应晶体管研究了跨这些良好特征晶界的电荷运输。此外，使用超敏感的亚带子光谱法评估了半导体带中陷阱状态的存在。传输数据和亚漏水吸收数据的相关性有助于阐明跨晶界的传输瓶颈的性质。除运输外，还研究了晶粒结构对半导体电子稳定性的影响以及从大气中吸附的极性分子在调整晶界的电子性能中的作用。通过将这些研究作为晶界结构的函数进行，可以完整地了解结构在管理晶界的电子特性中的作用，从而出现。这种电子材料家族的多功能性可以合成和功能化以表现出广泛的特性，它有望通过有机半导体以及太阳能电池和化学传感器实现整个电子电路。但是，由于这些材料是由弱分子间力固定在一起的，因此它们遭受了缺陷或缺陷的存在。该研究项目旨在阐明缺陷如何影响有机半导体的电子行为。特别是该项目的重点是膜中形成的晶体之间的边界，这通常限制了电子材料的性能。通过制造模型系统，在这些边界受到良好控制的情况下，这些边界的结构对电子性质的影响。该研究的社会影响会被外展活动扩大。例如，远程光学显微镜和高中生在微观和纳米级学习材料，在结构（如在显微镜中观察到）和特性之间提供了直接联系。