Quasi-2D n-Type Semiconducting Polymers: Novel Monomers, Synthesis, and Enhanced Electron Transport and Photovoltaic Properties

为了解决为不断增长的世界人口提供低成本、无污染的清洁能源这一社会重大挑战，需要有可能彻底改变能量转换和存储技术的新型半导体材料和器件。创造新一代的电子设备和信息技术也需要这些材料。该项目旨在开发创造新的基于塑料的电子传输半导体材料所需的基础知识，这种材料结合了增强的电荷传输和光吸收特性，并且易于加工成机械坚固的柔性薄膜。该项目的结果可能会导致新一代的高性能半导体塑料，适用于各种能量转换和存储技术。该项目还与可持续性有关，因为与无机氧化物相比，电子传输半导体聚合物有望成为低成本、可持续和可扩展制造的材料，与无机氧化物相比，无机氧化物目前广泛用于光电化学电池的光阳极，用于高效生产燃料（例如水电池中的氢）。在光伏应用中，电子传输聚合物可以实现坚固耐用的全聚合物器件，与目前更昂贵的无机器件相比，这种器件可以大规模廉价地制造。项目成果将通过同行评议的期刊出版物和会议报告进行传播。该项目为在半导体材料和能源科学与技术等高度跨学科领域培训包括妇女和少数民族在内的科学家和工程师提供了广泛的机会，这些领域需要化学、物理、材料科学、数学和工程方面的知识。该项目还将通过将研究成果整合到首席研究员教授的研究生和本科生课程中，从而改善课程设置。PI与日本、韩国、英国和法国的科学家在半导体材料、电子器件和能量转换器件的一般领域进行了许多研究合作，并接待了来自这些国家的高级科学家和学生的访问。该项目将加强这些国际合作，并为学生提供全球培训的视角。合适的n型半导体聚合物的稀缺性限制了对这类材料中电子传输的基本理解，限制了用于塑料电子器件的p-n互补逻辑电路、高效全聚合物太阳能电池、用于高效制氢的光电电池的光阳极、用于可充电电池的高能量/功率密度存储的电极和p-n热电器件的发展。提出的研究将解决n型半导体聚合物领域的基础科学挑战。该项目的总体目标是创建和研究一类具有准二维电子离域和增强电子传输特性的新型n型半导体聚合物，适用于电子设备和能量转换和存储应用。计划的研究将：(1)设计，合成和开发芳烯双苯并咪唑作为适合设计共轭聚合物的新型缺电子构建单元单体；(2)设计、合成并表征基于芳烯双苯并咪唑的准二维n型半导体聚合物；(3)研究新型芳烯双苯并咪唑聚合物的自组装和本体形貌、电子结构、光学和电子输运性质；(4)探索最有前途的新型n型导电聚合物作为全聚合物太阳能电池的受体材料，并研究其共混形态、光伏性能和潜在的结构-性能关系。该研究结果将改变对n型半导体聚合物在各种电子器件以及能量转换和存储器件中的基本认识、开发和应用，并有助于可持续发展。

PART 1: NON-TECHNICAL SUMMARYNovel semiconductor materials and devices that could potentially revolutionize energy conversion and storage technologies are needed to address society's grand challenge of supplying low cost and pollution-free clean energy for a growing world population. Such materials are also needed to create new generations of electronic devices and information technologies. This project aims to develop the basic knowledge needed for creating new plastic-based electron-transporting semiconducting materials that combine enhanced charge transport and light-absorbing properties with ease of processing into mechanically rugged flexible thin films. Results from the project may lead to new generations of high performance semiconducting plastics suitable for applications in diverse energy conversion and storage technologies. The project is also relevant to sustainability in that electron transporting semiconducting polymers show promise to be low-cost, sustainable, and scalable-manufactured materials with improved properties compared to inorganic oxides now widely used in photoanodes for photoelectrochemical cells for efficient production of fuels (e.g. hydrogen in aqueous cells). In photovoltaic applications, electron transporting polymers could enable rugged all-polymer devices which could be manufactured cheaply on a large scale compared to current more expensive inorganic devices. Project results will be disseminated through peer-reviewed journal publications and conference presentations. The project provides extensive opportunities for training scientists and engineers, including women and minorities, in the highly interdisciplinary fields of semiconductor materials and energy science and technologies, which require knowledge of chemistry, physics, materials science, mathematics, and engineering. The project will also enable curriculum improvements by integration of research findings into the graduate and undergraduate courses taught by the principal investigator (PI). The PI has many research collaborations with scientists in Japan, South Korea, UK, and France in the general areas of semiconductor materials, electronic devices, and energy conversion devices and has hosted visits by senior scientists and students from these countries. This project will strengthen those international collaborations and provide a global training perspective for the students. PART 2: TECHNICAL SUMMARYThe scarcity of suitable n-type semiconducting polymers has limited the fundamental understanding of electron transport in this class of materials and the development of p-n complementary logic circuits for plastic electronics, highly efficient all-polymer solar cells, photoanodes for photoelectrochemical cells for efficient hydrogen production, electrodes for high energy/power density storage in rechargeable batteries, and p-n thermoelectric devices. The proposed research will address the basic scientific challenges in the field of n-type semiconducting polymers. The overall goal of the project is to create and investigate a novel class of n-type semiconducting polymers with quasi-2D electronic delocalization and enhanced electron transport properties suitable for electronic devices and energy conversion and storage applications. The planned research will: (1) design, synthesize, and develop arylene bisbenzimidazoles as novel electron-deficient building block monomers suitable for the design of conjugated polymers; (2) design, synthesize, and characterize arylene bisbenzimidazole-based quasi-2D n-type semiconducting polymers; (3) investigate the self-assembly and bulk morphology, electronic structure and optical and electron transport properties of the novel arylene bisbenzimidazole polymers; and (4) explore the most promising new n-type conducting polymers as acceptor materials in all-polymer solar cells and investigate the blend morphology, photovoltaic properties, and underlying structure-property relationships. Results of the proposed study could transform the basic understanding, development and applications of n-type semiconducting polymers in diverse electronic devices as well as energy conversion and storage devices, and contribute to sustainability.