CAREER: Molecular Engineering of Charge Transfer in Polymeric Materials

技术摘要：在半导体行业朝着有源元件小型化的方向发展的过程中，出现了一些重大挑战。类似地，需要开发具有定义良好的结构、异质性和通过分子设计控制性能的聚合物。为了弥合聚合物化学和纳米结构半导体之间的差距，哥伦比亚大学的这个职业项目专注于开发含有电子供体和受体分子的光活性非均相侧链嵌段共聚物(HSBCP)。其目的是控制不同种类的层次结构，并了解它们的光物理。实现三个目标将检验中心假设，该假设建立在HSBCP可以被设计成能够产生能够进行有效电子转移的纳米结构的施主-受体结的概念上。首先，将开发一类新的具有微调最低未占据分子轨道(LUMO)能级的电子受体介原。其次，控制含有新型电子受体和其他给体的多相HSBCP的微相分离的能力将通过薄膜和块体中的几种X射线散射和成像技术来表征。第三，对聚合物结构、形态和非均相分子组成的定位的全面控制是本项目中材料的关键特征，这将通过泵浦-探测技术来表征材料的光物理特性。该项目的成功可能会影响可再生能源，并提供对人工光合作用的基本了解。非技术摘要：阐明有机材料在人工光合作用和太阳能发电中的功能是一个包括从分子到纳米结构到大规模设备的多个长度尺度的挑战。聚合物的使用可以提供控制异质分子组装的手段，以模拟自然界的光合作用纳米机器。有鉴于此，PI将设计和合成具有独特分子结构的新材料，并研究其产生的光学和电子性能。这个关于新型聚合物材料的项目将使学生接触到跨越化学、物理和工程领域的不同学科。此外，学生将通过建立的合作关系在国家实验室和其他机构获得第一手研究经验。外展部分将侧重于来自布朗克斯的中学生，以及对研究职业感兴趣的有抱负的本科生。来访的中学生将亲身感受到大学的氛围，并在实验室环境中进行实验。与以少数族裔为主的本科院校的接触将是主要的重点，花时间与学生在一起，为他们提供建议和指导，使他们成为有竞争力的研究生院申请者。这一职业项目的一个重要成果是加强哥伦比亚大学研究生和本科生的材料课程。这些组成部分将通过外联和课堂活动影响多个层次的教育，希望培养学生在科学或工程领域接受高等教育的兴趣。

TECHNICAL SUMMARY: A number of grand challenges have emerged in the semiconductor industry as it moves toward the miniaturization of the active components. Similarly, there is a need to develop polymers with well-defined architectures, heterogeneity, and control of properties through molecular design. To bridge the gap between polymer chemistry and nanostructured semiconductors, this CAREER project at Columbia University is focused on the development of photoactive heterogeneous side-chain block copolymers (HSBCPs) bearing electron donor and acceptor molecules. The purpose is to control heterogeneous hierarchical structures and understand their photophysics. Fulfilling three objectives will test the central hypothesis, which is founded on the concept that HSBCPs can be engineered to yield nanostructured donor-acceptor junctions capable of undergoing efficient electron transfer. First, a family of new electron acceptor mesogens with finely tuned lowest unoccupied molecular orbital (LUMO) levels will be developed. Second, the ability to control the microphase segregation of heterogeneous HSBCPs containing novel electron acceptors and other donors will be characterized by several X-ray scattering and imaging techniques in thin films and in the bulk. Third, the overall control of polymer structure, morphology, and positioning of heterogeneous molecular components are the key features of the materials in this project, which will be evaluated by pump-probe techniques to characterize the photophysics of the materials. The success of this project could impact renewable energy, and provide a fundamental understanding of artificial photosynthesis.NON-TECHNICAL SUMMARY: Elucidating the function of organic materials in artificial photosynthesis and solar-energy generation is a challenge encompassing multiple length scales, from molecules to nanostructures to large-scale devices. The use of polymers can provide the means to control heterogeneous molecular assemblies to mimic nature's photosynthetic nanoscale machinery. With this in mind, the PI will design and synthesize new materials with unique molecular architectures and study their resulting optical and electronic properties. This project on new polymeric materials will expose students to various disciplines spanning fields across chemistry, physics, and engineering. Additionally, the students will get first-hand research experience in National Labs and other institutions through established collaborations. The outreach component will focus on middle-school students from The Bronx, as well as aspiring undergraduates interested in research careers. Visiting middle-school students will get personal exposure to the college atmosphere and running experiments in a lab setting. Outreach to predominantly minority-serving undergraduate institutions will be the main focus, spending time with students to provide them with advice and guidance to become competitive applicants for graduate school. A key outcome of this CAREER project is aimed at strengthening the materials curricula at the graduate and undergraduate levels at Columbia University. These components will impact multiple levels of education through outreach and classroom activities, with the hope of instilling interest in students to pursue higher education in the science or engineering fields.