Reframing the Structure and Synthesis of Semiconducting Polymers

Organic Electronics offer the potential of a lightweight, mechanically flexible, and inexpensive platform for the growing number of electronic devices that enable and power modern society. From the microelectronic circuits that enable portable devices such as watches, phones, and E-readers to the light absorbing semiconductors that provide roof-top solar, electroactive organic polymers have the potential to replace traditional and expensive materials that are often difficult to access. This project aims to develop a new class of semiconducting organic polymers that are scalable, accessible, and robust in real-world electronics applications. The work proposed will focus on transforming everyday plastics into electrically conductive polymers that will be printed into thin films and integrated into electronic devices. The studies proposed will accelerate the development of understanding of the connections between polymer molecular structure and electronic function. This project will also serve to train the next generation of scientists by engaging not only graduate students but also local community college students in the Los Angeles area. Conjugated polymers have defined solution processable organic electronics for decades with maturing applications in organic solar cells, transistors, and bioelectronics. However, these materials suffer from several deficiencies including poor environmental stability, limited mechanical properties, and a narrow suite of synthetic techniques, limiting broad access to advanced architectures and novel function. The focus of this proposal is a strategy to develop and invigorate an underexplored class of semiconducting polymers based on non-conjugated backbones bearing electronically active pendant groups, termed non-conjugated pendant electroactive polymers (NCPEPs). Stereoregularity (tacticity) is identified as an under-utilized structural handle for maximizing charge transport and the ultimate potential of these polymers. This class of polymers promises to expand both the scope of viability and application in organic electronics. Towards these ends the objectives of the proposed work are to develop living polymerization methods amenable to the scalable, accessible, and stereocontrolled synthesis of NCPEPs, to elucidate interrelated aspects of backbone and pendant structure, and to optimize structural characteristics of pendant polymers that enable enhanced electronic properties. The vision of the proposed work is the development of a stable, robust platform for organic electronics that is driven by powerful synthetic capabilities and enabling of novel function. An integrated set of activities focused on engaging regional community college students and undergraduate education in plastics sustainability demonstrate the broader impact of the proposed work. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.