CAREER: Molecular Engineering of Charge Transfer in Polymeric Materials

技术概要：随着半导体工业朝着有源元件小型化的方向发展，在半导体工业中出现了许多巨大的挑战。类似地，需要开发具有明确定义的结构、异质性和通过分子设计控制性质的聚合物。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CAREER项目的重点是开发具有电子供体和受体分子的光敏异质侧链嵌段共聚物（HSBCP）。其目的是控制异构的层次结构，并了解其物理特性。实现三个目标将测试中心的假设，这是建立在这样的概念，即HSBCPs可以被设计成产生纳米结构的供体-受体结能够进行有效的电子转移。首先，一个家庭的新的电子受体介晶与微调最低未占分子轨道（LUMO）的水平将被开发。第二，控制含有新型电子受体和其他供体的异质HSBCPs的微相分离的能力将通过几种X射线散射和成像技术在薄膜和散装的特点。第三，聚合物结构、形态的整体控制以及异质分子组分的定位是本项目材料的关键特征，将通过泵浦-探测技术进行评估，以表征材料的微物理特性。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理解。非技术性总结：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项挑战，涉及从分子到纳米结构再到大规模设备的多个长度尺度。聚合物的使用可以提供控制异质分子组装以模拟自然界的光合纳米级机器的手段。考虑到这一点，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特性。 这个关于新聚合物材料的项目将使学生接触到跨越化学，物理和工程领域的各种学科。此外，学生将获得第一手的研究经验，在国家实验室和其他机构通过建立合作。外联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。访问中学生将获得个人接触到大学的气氛和在实验室环境中运行的实验。外联到主要少数民族服务的本科院校将是主要的重点，花时间与学生，为他们提供咨询和指导，成为研究生院有竞争力的申请人。这个职业项目的一个关键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.