CAREER: Morphology and Property Correlations of Chemically Doped 1D Conjugated Polymer Aggregates

该项目由材料研究部的聚合物项目和刺激竞争研究的实验项目（EPSCoR）共同资助。非技术概述：本项目的研究目标是获得化学掺杂一维导电聚合物聚集体的纳米级形貌与光电性能之间关系的基础知识。计划的研究和教育活动通过解决当前国家在物质和人力资源发展方面的需求具有广泛的影响。在项目中获得的知识将促进电子应用中更有效的有机材料的合理设计，以及未来有机电子器件的更有效的加工和制造技术。随着目前世界有机电子市场规模预计将在未来十年显著增长，仅一小部分有机电子材料的改进就可能对美国和全球经济产生影响。该项目还为参与的学生提供了一个平台，以获得跨学科领域的专业知识，包括材料科学，化学和表面科学。包括高分子科学和纳米科学的实践活动将提供给K-8学生早期接触科学主题。高中聚合物纳米科学研讨会将为学生提供制备和表征功能纳米结构的实践经验。额外的努力将致力于招募和吸引代表性不足和经济弱势的K-12，本科生和研究生参加这些外展活动。这些综合研究和教育活动的成功实施将增强美国科学研究的多样性，并激励更多的K-12和本科生从事STEM职业。技术概述：通过基于afm的方法获得的非掺杂和掺杂一维共轭聚合物聚集体的系统局部形态-性质相关性是本项目的主要目标。为了实现这一目标，本项目选择了单层和多层共轭聚合物纳米须作为模型系统，因为单层纳米须中的大多数聚合物分子是表面分子，可以通过表面表征工具直接研究。多层纳米晶须将在单层纳米晶须的基础上，以“逐层”的方式进行研究。利用原子力显微镜及其先进模式分析了掺杂和非掺杂共轭聚合物纳米须的局部形貌-性能关系。用紫外可见光谱法系统地研究了溶液中的掺杂反应，揭示了许多参数，特别是聚集形式对化学掺杂反应动力学的影响。一维共轭聚合物聚集体内部和之间的电荷输运也将在纳米尺度上进行研究。该计划有望揭示在纳米到微米尺度上的结构和性质波动，否则这些波动将隐藏在集合测量中。纳米晶须内部和纳米晶须之间的电导率研究将阐明缺陷位点、有序/无序结构域、连接点和化学掺杂对共轭聚合物材料电荷输运的相互作用。化学掺杂反应动力学对反应条件的依赖，特别是共轭聚合物微观聚集形式的研究结果，将为基于溶液的实际应用提供重要的宏观掺杂反应动力学信息，这些信息目前在很大程度上是缺失的。本项目积累的对共轭聚合物化学掺杂的全面了解，将使该领域的研究人员能够基于具体的有机掺杂知识，而不是通过经验试验来寻求合适的策略。

This project is jointly funded by the Polymers Program in the Division of Materials Research and the Experimental Program to Stimulate Competitive Research (EPSCoR).NON-TECHNICAL SUMMARY:The research objective of this CAREER project is to gain fundamental knowledge of the correlation between morphology at the nanoscale and optoelectronic properties of chemically doped one-dimensional conducting polymer aggregates. The planned research and educational activities have broad impacts by tackling current national needs in both materials and human workforce development. The knowledge gained in the project will promote rational design of more efficient organic materials for electronic applications, as well as more efficient processing and fabrication techniques for future organic electronic devices. With the current world organic electronics market size expected to grow significantly in the next decade, enhancements on just a fraction of the organic electronic materials could have an impact on US and global economy. This program also provides a platform for participating students to gain expertise from interdisciplinary fields including materials science, chemistry, and surface science. Hands-on activities involving polymer science and nanoscience will be offered to K-8 students for early exposure to scientific topics. High-school polymer nanoscience workshops will provide students hands-on experience on preparing and characterizing functional nanostructures. Extra efforts will be devoted to recruiting and involving underrepresented and economically disadvantaged K-12, undergraduate, and graduate students into these outreach activities. Successful execution of these integrated research and education activities will enhance diversity in US scientific research and inspire more K-12 and undergraduate students to pursue STEM careers.TECHNICAL SUMMARY:The systematic local morphology-property correlation of non-doped and doped 1D conjugated polymer aggregates gained by AFM-based methods is the primary goal of this project. To achieve this goal, monolayer and multi-layer conjugated polymer nanowhiskers are chosen as the model systems in this program because most of the polymer molecules within monolayer nanowhiskers are surface molecules that can be directly investigated by surface characterization tools. Multi-layer nanowhiskers will be subsequently studied in a "layer-by-layer" manner on the basis of what was learned from monolayer nanowhiskers. Local morphology-property relationship for doped and non-doped conjugated polymer nanowhiskers will be analyzed using AFM and its advanced modes. The doping reaction in solution will be systematically studied by UV-vis spectroscopy to reveal the influences of many parameters, particularly the aggregation forms, on the chemical doping reaction kinetics. The charge transport in and between 1D conjugated polymer aggregates will also be interrogated at nanometer scale. This program is expected to reveal structure and property fluctuations at nano- to micrometer scales that are otherwise hidden in ensemble measurements. The conductivity studies within and between nanowhiskers will elucidate the interrelated roles of defect sites, ordered/disordered domains, connection points, and chemical doping on the charge transport of conjugated polymer materials. The results of the chemical doping reaction kinetic dependence on the reaction conditions, especially conjugate polymer microscopic aggregation forms, will supply practical solution-based applications with crucial macroscopic doping reaction kinetics information that is largely missing so far. The comprehensive understanding of the chemical doping of conjugated polymers accumulated in this program will enable researchers in this field to seek suitable strategies based on concrete organic doping knowledge rather than through empirical trials.