Structure and Properties of Defects in Organic Molecular Semiconductors

技术概述：人们对使用聚合物和有机分子材料来构建各种光电活性器件一直有着浓厚的兴趣。尽管这些材料的重要性，有机分子膜的形态和它的宏观性质之间的关系仍然不完全理解。 有机分子晶体中结构缺陷的性质及其对宏观性质的影响仍需详细确定。由于这些固体的延伸的分子连接性，晶界（2-D）、位错（1-D）和空位（0-D）缺陷的能量、结构和迁移率可能与无机晶体中所见的完全不同。我们一直致力于光电活性有机分子和聚合物材料中特定缺陷结构和性质的基础研究。最近，我们研究了TIPS-并五苯的加工和结构，这是一种与并苯环面对面包装的可溶性变体。 我们开发了低剂量高分辨率电子显微镜（HREM）成像技术，用于直接观察结晶和液晶聚合物和有机分子膜中的缺陷微观结构。 现在，我们提出了额外的研究并五苯变体的结构和性质的功能设计，以更好地控制其固态包装和宏观性能。 我们将集中我们的努力，旨在提高在有机溶剂中的溶解度，稳定液晶中间相的形成，并促进固态并苯环之间的面对面包装的并五苯衍生物系列。这些新材料的结构表征将利用密歇根大学提供的各种仪器，包括光学显微镜，宽角和小角X射线散射，扫描电子显微镜，扫描探针显微镜和透射电子显微镜。 该建议的智力优点是其专注于有机电子器件的一系列新的高度结晶的官能化并五苯衍生物的特征形态和缺陷结构。 我们将确定这些新材料的微观结构和宏观性能之间的关系。我们希望我们的研究结果将继续用于优化现有材料的加工条件和激励未来的分子设计。非技术性总结：人们对开发有机分子和聚合物材料用于“塑料电子”应用如射频识别标签、柔性显示器和生物传感器有相当大的兴趣。 该项目将使用密歇根大学提供的先进显微技术研究这些材料的详细微观结构。 所获得的信息将使设计具有更高性能的新材料成为可能。 该项目将涉及对材料科学与工程研究生的全职支持，还将通过大学研究机会计划（UROP），女性工程学生的玛丽安萨拉帕克计划，少数民族工程计划办公室（MEPO），高中生的NASA/夏普暑期计划，以及与安阿伯的格林希尔高中合作的暑期研究项目。

TECHNICAL SUMMARY:There is intense continuing interest in the use of polymer and organic molecular materials for the construction of a variety of optoelectronically-active devices. Despite the importance of these materials, the relationship between the morphology of the organic molecular film and its macroscopic properties remains incompletely understood. The nature of the structural defects in organic molecular crystals and their influence on macroscopic properties still needs to be determined in detail. Because of the extended molecular connectivity of these solids, the energetics, structure, and mobility of the grain boundary (2-D), dislocation (1-D), and vacancy (0-D) defects can be quite different than those seen in inorganic crystals. We have been focusing on fundamental studies of specific defect structures and properties in organic molecular and polymer materials that are optoelectronically active. Most recently, we have investigated the processing and structure of TIPS-pentacene, a soluble variant that packs with the acene rings face-to-face. We have developed Low Dose High Resolution Electron Microscopy (HREM) imaging techniques for the direct observation of defect microstructures in crystalline and liquid crystalline polymers and organic molecular films. We now propose additional studies on the structure and properties of pentacene variants with functionalities designed to better control their solid-state packing and macroscopic properties. We will concentrate our efforts on a series of pentacene derivatives designed to enhance solubility in organic solvents, stabilize the formation of liquid crystalline mesophases, and promote face-to-face packing between the acene rings in the solid-state. The structural characterization of these new materials will take advantage of a variety of instrumentation available at the University of Michigan including Optical Microscopy, Wide and Small Angle X-ray Scattering, Scanning Electron Microscopy, Scanned Probe Microscopy, and Transmission Electron Microscopy. The intellectual merit of this proposal is its focus on the characteristic morphologies and defect structures of a new series of highly crystalline, functionalized pentacene derivatives of interest for organic electronic devices. We will determine relationships between the microstructure and the macroscopic properties of these new materials. We expect that our results will continue to be useful for optimizing processing conditions of existing materials and for motivating future molecular designs. NON-TECHNICAL SUMMARY: There is considerable interest in the development of organic molecular and polymer materials for "plastic electronic" applications such as radio-frequency identification tags, flexible displays, and biosensors. This project will investigate the detailed microstructure of these materials using advanced microscopic techniques available at the University of Michigan. The information obtained will make it possible to design new materials with enhanced performance. The project will involve full-time support for a graduate student in Materials Science and Engineering, and will also provide research experience for undergraduates through the University Research Opportunity Program (UROP), the Marian Sarah Parker program for female engineering students, the Minority Engineering Program Office (MEPO), the NASA/Sharp summer program for high school students, and an outreach summer research program with Greenhills High School in Ann Arbor.