Understanding Carrier Delocalization and Transport in Micelle Forming Amphiphilic Conjugated Polymers

了解形成胶束的两亲性共轭聚合物中的载流子离域和传输

• 批准号: 2305152
• 负责人: Sarah Tolbert
• 金额: $ 80万
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2305152&HistoricalAwards=false
• 关键词: Understanding; Carrier; Delocalization; Transport; Micelle

With the support of the Macromolecular, Supramolecular and Nanochemistry program in the Division of Chemistry, Professors Sarah H Tolbert, Benjamin J Schwartz and Yves Rubin of the University of California at Los Angeles are systematically studying assemblies of semiconducting polymers in aqueous solutions in order to seek more favorable geometries for electrical conductivity. Semiconducting polymers are an exciting class of optoelectronic materials because of their solution processability, low cost, and structural tunability. These characteristics make them useful in a range of organic electronic devices, including photovoltaics, thermoelectrics, light-emitting diodes, and transistors. However, the conformational freedom of conjugated polymers leads to intrinsic disorder that can result in poor electrical conductivity and hence limited commercial applicability. This research will address these issues and use organic synthesis, structural studies, and modern spectroscopy to explore water-soluble amphiphilic semiconducting polymers that self-assemble into cylindrical micelles as a way to straighten polymer chains and reduce defects without the need for a crystalline network. The efforts toward controlling polymer self-assembly while interrogating chain conformation with respect to carrier mobility have the potential for broad impact in the field of organic electronics and could lead to a development of new and low-cost polymeric systems for a variety of applications in which temperature and/or light are converted to electricity and vice versa. The project will provide opportunities for undergraduate and graduate students to be involved in cutting-edge interdisciplinary research. In an effort to bring the ideas of nanostructured materials, organic electronics, and self-assembly to a broader audience, experiments related to this work will be brought to secondary school classrooms throughout the greater Los Angeles area via a series of graduate-student run workshops for teachers. This research will focus on the synthesis of micelle-forming amphiphilic conjugated polymers based on poly(cyclopentadithiophene)-alt-thiophene (PCT) backbones, and will investigate of how their assembled structure controls charge mobility upon doping. In the first objective, organic synthesis and amphiphilic assembly will be used to precisely control the position of charge-balancing counterions in chemically-doped PCT polymers. PCT-based polymers with cationic, anionic, non-ionic, and zwitterionic size chains will be prepared and solution-phase small-angle X-ray scattering (SAXS) will be used to characterize micelle formation. Doping will be achieved with iron(III) salts in water and the number and nature of charge carriers will be probed using steady-state and transient IR/visible absorption spectroscopy. Based on theoretical calculations and modeling, doubly charged side chains and/or divalent solution-phase counterions will be employed to control polaron pairing into bipolarons at high doping densities. In order to create systems where the anionic side chains serve as counterions for the polarons, copolymers of anionic and either zwitterionic or non-ionic polymers will be applied. Such an approach will eliminate the need for additional ions in solution. The second objective will target new polymer backbones that are easier to chemically dope. The final goal will seek to develop methods to transition optimized assemblies from aqueous solutions into the solid state to create new materials with improved conductivity. The comprehensive approach for controlling polymer conformation and charge localization associated with this research has the potential to provide important strategies to further understand fundamental charge carrier dynamics in conjugated polymers.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在化学系中的大分子，超分子和纳米化学计划的支持下，加利福尼亚大学洛杉矶大学的莎拉·托尔伯特（Sarah H Tolbert），本杰明·施瓦茨（Benjamin J Schwartz）和伊夫·鲁宾（Yves Rubin）系统地研究了在水溶液中，以寻求更有利的电动机的半导体聚合物组合，以寻求更有利的电动仪，以寻求更有利的电动机。 半导体聚合物是一类令人兴奋的光电材料，因为它们的解决方案可加工性，低成本和结构性可调性。 这些特征使其在一系列有机电子设备中有用，包括光伏，热电，发光二极管和晶体管。 但是，共轭聚合物的构象自由会导致内在疾病，从而导致电导率差，因此商业适用性有限。 这项研究将解决这些问题，并使用有机合成，结构研究和现代光谱探索水溶性两亲性半导体聚合物，这些聚合物会自我组装成圆柱形胶束，以拉直聚合物链并减少无需结晶网络而减少聚合物链。 控制聚合物自组装的努力，同时询问有关载体迁移率的链构象的构型在有机电子产品领域产生广泛影响，并可能导致新的和低成本的聚合物系统开发用于各种应用，在这些应用中，温度和/或光转化为电力，反之亦然。 该项目将为本科生和研究生提供机会参与尖端的跨学科研究。为了将纳米结构材料，有机电子设备和自组装的想法带到更广泛的受众群体中，与这项工作相关的实验将通过一系列教师的研究生工作坊将与这项工作相关的实验带到整个大洛杉矶地区的中学教室。这项研究将重点介绍基于聚（环戊二硫代） - 甲苯（PCT）骨架的胶束形成两亲性共轭聚合物的合成，并将研究其组装结构如何控制掺杂时电荷迁移率。 在第一个目标中，有机合成和两亲和组装将用于精确控制化学掺杂PCT聚合物中电荷平衡柜台的位置。 将准备具有阳离子，阴离子，非离子和zwittionic尺寸链的基于PCT的聚合物，并且将使用溶液 - 相的小角度X射线散射（SAX）来表征胶束的形成。 用水中的铁（III）盐将实现掺杂，并将使用稳态和瞬态IR/可见吸收光谱探测电荷载体的数量和性质。 基于理论计算和建模，将采用双带电的侧链和/或二价溶液 - 相对柜台来控制高掺杂密度以高掺杂密度为双极。为了创建阴离子侧链充当极性子的相反物的系统，将应用阴离子的共聚物以及Zwitterionic或非离子聚合物。这种方法将消除溶液中其他离子的需求。 第二个目标将针对新的聚合物骨架，更容易化学涂料。 最终目标将寻求开发方法，以将其从水溶液中过渡到固态，以创建具有改善电导率的新材料。 与本研究相关的聚合物构象和电荷定位的全面方法具有潜力，可以提供重要的策略，以进一步了解共轭聚合物中的基本费用载体动力学。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子和更广泛影响的评估来通过评估来获得支持的。