Collaborative Research: Charge Transport Pathways in Semiconducting Polymer Films

North Carolina State University, Raleigh NC

Investigators

Abstract

TECHNICAL SUMMARY The connection between charge transport and molecular order on intermediate length scales in films of semiconducting polymers will be examined. In most electrical devices, semiconducting polymer chains do not span the distance between the electrodes and the resulting electrical properties are the result of charge transport both along the chains and from chain-to-chain. Through a collaborative effort between scientists at UCSB and NCSU the charge transport pathways in semiconducting polymers will be studied by: 1) measuring the in-plane bulk and interface correlation length of the backbone of semiconducting polymers using a combination of physical and electrical characterization methods and 2) investigating transport in model block co-polymer systems with varying energetic structure to uncover how both positive and negative carriers are transported in complex systems. This work will use a novel polarized soft X-ray scattering method to probe the backbone correlation length that will enable a greater understanding of the connection between morphology and electrical transport. The scattering techniques developed in this work will have impact on characterization of both semiconducting and conventional polymers. NON-TECHNICAL SUMMARY Conjugated polymers have tremendous potential for use in cheap, flexible, light-weight devices as transistors in simple circuits, light emitting diodes, and solar cells. Improvement of our control of the properties of electrically conducting polymers will enable new types of electronic devices for use in energy conversion and biomedical diagnostics. This work will focus on the determination of the pathways of charge transport in conjugated polymers. Research in polymer electronics is highly multidisciplinary and will provide training for graduate students in materials science, chemistry, and microelectronics. The PIs and graduate students will also provide lab space and training for promising undergraduate students from underrepresented groups to advance their future careers in science and engineering. Outreach to children to promote science education in the local school districts will be done through demonstrations of flexible electronics devices by graduate student researchers at local science nights.