Charge transport in semiconducting polymers : connecting microstructure to electronic properties
- Organic semiconductors have emerged as an alternative to conventional silicon-based electronics in a number of large-area applications including lighting, displays, and sensors. Their ease of processing and compatibility with solution-based deposition techniques makes them attractive for low-cost, roll-to-roll production processes. However, despite significant progress in recent years, the electronic performance of these materials remains modest relative to silicon, limiting their potential applications. In order for organic semiconductors to truly flourish in industry, electronic figures of merit such as charge carrier mobility must be improved further. The material microstructure is one of the key determinants of charge carrier mobility in organic semiconductors. While many new microstructure characterization tools have been developed and our understanding of the relationship between microstructure and electronic properties has greatly improved, significant questions remain, limiting our ability to rationally design and process new materials with improved performance. The focus of this dissertation has been in attempting to improve this understanding. In this dissertation, I discuss several ways in which the microstructure of semiconducting polymers affects their electronic properties. First, I present a procedure for determining the precise thin-film structure of a semiconducting polymer using two-dimensional grazing incidence X-ray diffraction. These packing structures can then be used in a variety of electronic structure calculations. Next, I discuss the role of molecular weight distribution as well as the impact of film confinement on the microstructure and electronic properties of two semicrystalline polythiophenes. I show how disorder, crystallinity, and chain orientation are strongly influenced by these factors and quantify their impact on charge carrier mobility. Finally, I describe our latest understanding of the factors governing charge transport in state-of-the-art materials. I suggest that disorder is an inextricable feature of semiconducting polymers that need not be highly detrimental to charge transport if it is embraced and planned for by designing materials which are resilient to this disorder.
|Type of resource
|electronic; electronic resource; remote
|1 online resource.
|Stanford University, Department of Materials Science and Engineering.
|Toney, Michael Folsom
|Toney, Michael Folsom
|Statement of responsibility
|Submitted to the Department of Materials Science and Engineering.
|Thesis (Ph.D.)--Stanford University, 2015.
- © 2015 by Scott Himmelberger
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
Also listed in
Loading usage metrics...