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

University Of Washington, Seattle WA

Investigators

Abstract

PART 1: NON-TECHNICAL SUMMARY Novel 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 SUMMARY The 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.