Defect Manipulation in Pi-Conjugated Semiconducting Polymers and their Effect on Microstructure and Transport Properties

技术概要：π-共轭半导体聚合物正处于用于有机发光二极管、薄膜晶体管和太阳能电池的密集开发中。然而，由于难以建立结构-性质关系的详细相关性，对它们在许多应用中的性能的理解是有限的。这反过来又需要更深入地了解这些类型材料的结构发展和形成，这目前受到合成化学家无法精确控制π共轭半导体聚合物中缺陷的阻碍。该提案的目标是开发具有精确控制的缺陷的模型π共轭聚合物，以便可以开发对其微观结构的更完整描述，从而阐明微观结构如何影响光电性能。开始，模型聚合物将是聚（3-己基噻吩）（P3 HT），随着项目的进展，将研究其他聚合物系统。为了简化模型，将表征聚合物纳米线而不是半结晶薄膜，以便可以广泛地研究结晶域。随着工作的进展，在膜中的无序程度将系统地增加，以探索结晶和非晶域之间的相互作用，以及无序的π共轭半导体聚合物的光电性能的作用。非技术摘要：本提案旨在进一步理解越来越重要的一类材料，即π共轭半导体聚合物。这些聚合物在柔性电子产品的一般领域中引起了很大的兴趣，其目的是以更具成本效益和节能的方式开发便携式电子设备。这些聚合物越来越多地用于商业应用，例如有机发光二极管（OLED）。此外，它们正在积极开发用于可再生能源作为太阳能电池中的光吸收材料。尽管它们被广泛使用，但关于缺陷（例如，聚合物链中的扭结）如何影响聚合物的性质仍有很多未知之处。在这项提案中，聚合物中的缺陷将被系统地改变，以便对这些材料有更详细的了解。拟议的研究将通过太平洋科学中心、科学咖啡馆的社区外展活动以及为代表性不足的少数民族和妇女开展的辅导活动得到加强。该项目还包括针对本科生和高中生的教育活动。

TECHNICAL SUMMARY: Pi-conjugated semiconducting polymers are under intense development for use in organic light-emitting diodes, thin-film transistors, and solar cells. However, the understanding of their performance in many applications is limited because of the difficulty in establishing a detailed correlation of structure-property relationships. This in turn requires deeper understanding of structure development and formation of these classes of materials, which is currently hampered by the synthetic chemists' inability to precisely control defects in pi-conjugated semiconducting polymers. The goal of this proposal is to develop model pi-conjugated polymers with precisely controlled defects, so that a more complete description of their microstructure can be developed and therefore elucidate how the microstructure affects optoelectronic properties. The model polymer will be poly(3-hextylthiophene) (P3HT) to begin with, and as the project moves on other polymer systems will be investigated. To simplify the model, polymer nanowires will be characterized rather than the semi-crystalline thin film so that the crystalline domains can be studied extensively. As the work progresses, the degree of disorder in the films will be systematically increased in order to explore the interplay between the crystalline and amorphous domains, and the role of disorder in optoelectronic properties of pi-conjugated semiconducting polymers.NON-TECHNICAL SUMMARY: This proposal aims to further the understanding of an increasingly important class of materials, namely pi-conjugated semiconducting polymers. These polymers have been attracting a lot of interest in the general area of flexible electronics, where the aim is to develop portable electronic devices in a more cost-effective and energy-efficient manner. These polymers are increasingly being used in commercial applications, for example in organic light-emitting diodes (OLEDs). Furthermore, they are actively being developed for use in renewable energy as the light absorber material in solar cells. Despite their widespread usage, there is much that remains unknown about how defects (for example, kinks in the polymer chain) affect the polymers' properties. In this proposal, the defects in the polymers will be systematically altered so that a more detailed understanding of these materials can be developed. The proposed research will be enhanced by community outreach activities through the Pacific Science Center, the Science Cafe, and through mentoring activities for underrepresented minorities (URMs) and for women. The project also includes educational activities for undergraduate and high-school students.