Polymer Semiconductor Crystallization: The Oligomer "Bottom-Up" Approach

聚合物半导体结晶：低聚物“自下而上”方法

• 批准号: 1112455
• 负责人: Alejandro Briseno
• 金额: $ 34.5万
• 依托单位: University of Massachusetts Amherst
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-08-15 至 2014-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1112455&HistoricalAwards=false
• 关键词: Polymer; Semiconductor; Crystallization; Oligomer; Bottom

TECHNICAL SUMMARYPolymer semiconductors such as the alkyl-substituted polythiophenes have been the focus of interest because of their solution-processable nature and application in devices such as transistors and solar cells. Their carrier mobilities, however, are significantly lower than small-molecule semiconductors such as pentacene and rubrene. The lower mobility is attributed to the structural disorder associated with entangled polymer chains which result in smaller and less-aligned crystals that form grain boundaries in thin films. In order for polymer semiconductors to outperform small-molecule semiconductors and make their way to real world applications, a protocol for fabricating highly crystalline films must first be developed. The objective of this study is to develop a crystallization protocol by employing low molecular weight polymers, or oligomers. Our intent is to develop a structure-property relationship from these materials and determine the electronic and molecular properties of this class of oligomers. The approach to this project is to synthesize a series of oligomers from the benchmark building block, didodecylquaterthiophene, and then employ coupling chemistry to produce low molecular weight oligomers with well-controlled conjugation lengths and narrow polydispersities. The PI will also utilize oligomer single-crystalline films as test structures for measuring intrinsic carrier mobilities in field-effect transistors. The scientific outcome of the program will be a fundamental understanding of chain packing in low molecular weight polymers. This knowledge will help one to understand and ultimately control crystallization in higher molecular weight polymers. This work will also impact on how one can design polymers with controlled molecular weights and narrow polydispersities for growing highly crystalline films. NON-TECHNICAL SUMMARYFundamental knowledge of how molecules are arranged in polymer semiconductor crystals will be critical for the understanding of electrical transport in polymer thin films and devices. The approaches described in this project combine creation of new materials by chemical means, expertise in crystal growth, device fabrication, and an interdisciplinary way of solving problems, and are aimed toward understanding and optimization of how polymeric/organic electronic devices operate. The success of the proposed research program would be of importance toward our fundamental understanding of polymer crystallization on both the nano- and bulk length scales. The proposed studies will offer opportunities to train postdoctoral, graduate, and undergraduate students in synthesis, polymer science, and device fabrication. Principal Investigator (PI) Briseno will also be engaged in professional activities that have broader impact on society, the scientific community, and underprivileged students across the nation.

聚合物半导体，如烷基取代的多噻吩，由于其溶液可加工的性质和在晶体管和太阳能电池等器件中的应用，一直是人们关注的焦点。然而，它们的载流子迁移率明显低于小分子半导体，如并五苯和rubrene。较低的迁移率归因于与纠缠聚合物链相关的结构紊乱，这导致薄膜中形成晶界的更小和更不排列的晶体。为了使聚合物半导体的性能优于小分子半导体，并使其在现实世界中得到应用，必须首先开发出一种制造高结晶薄膜的方案。本研究的目的是通过采用低分子量聚合物或低聚物来开发结晶方案。我们的目的是发展这些材料的结构-性质关系，并确定这类低聚物的电子和分子性质。该项目的方法是以二十二烷基季噻吩为基础合成一系列低聚物，然后采用偶联化学方法合成具有良好控制共轭长度和窄多分散性的低分子量低聚物。PI还将利用低聚单晶薄膜作为测量场效应晶体管固有载流子迁移率的测试结构。该计划的科学成果将是对低分子量聚合物中的链式包装的基本理解。这些知识将有助于人们理解并最终控制高分子量聚合物的结晶。这项工作也将影响人们如何设计具有控制分子量和窄多分散度的聚合物，以生长高结晶薄膜。关于分子如何在聚合物半导体晶体中排列的基本知识对于理解聚合物薄膜和器件中的电输运至关重要。本项目所描述的方法结合了通过化学手段创造新材料、晶体生长、器件制造方面的专业知识和跨学科解决问题的方法，旨在理解和优化聚合物/有机电子器件的操作方式。该研究计划的成功将对我们在纳米和体长尺度上对聚合物结晶的基本理解具有重要意义。拟议的研究将为培养合成、聚合物科学和设备制造方面的博士后、研究生和本科生提供机会。首席研究员（PI）布里塞诺还将从事对社会、科学界和全国贫困学生产生更广泛影响的专业活动。