Polarons, disorder and charge transport in polymeric semiconductors
Abstract/Contents
- Abstract
- Polymeric semiconductors are an exciting group of materials with the potential to enable a new generation of solution-processable, flexible electronics for a wide variety of applications. Due to their complex microstructure, however, it can be difficult to determine the structure-property relationships that govern polymer performance. For the development of new, high performing polymers, a better understanding of the polymer microstructure and the processes that limit charge transport in both doped and undoped polymeric semiconductors is crucial. In this dissertation, I focus on understanding how the polymer microstructure influences charge transport. First, I present experimental evidence supporting the findings of a new, vigorous and complete theoretical model, crucial for interpreting infra-red (IR) studies of polaron absorption in order to glean rich information about the local, nanoscale packing of the polymer. Through a combination of experimental measurements with theoretical simulations, these IR studies reveal the link between disorder, polaron localization, and charge transport in polymers. By correlating polaron measurements in a model polymer system to independent studies of carrier mobility, I provide direct evidence demonstrating the effect of charge delocalization and crystallite connectivity on charge transport. Next, I discuss the effect of doping on the polymer microstructure and charge transport at various dopant loadings. When dopants are present in trace amounts, I show that measurable changes in the local hole environment and polymer conformation occur, influencing the carrier mobility. At high dopant loadings on the other hand, a series of complementary spectroscopy techniques are used to gain further insight into the doping mechanism in polymers, as well as the potential to use doping as a method of tuning polymer morphology. Finally, I use the techniques developed in this dissertation to study a novel high performing donor-acceptor copolymer material, demonstrating the general applicability of the experimental strategies outlined for revealing insights into the local nanoscale disorder and charge transport in polymer semiconductors. An understanding of how the different microstructural features influence charge transport in polymeric semiconductors at multiple length-scales, as explored in this dissertation, is important for material design and will serve to inform the engineering of new, improved organic electronic devices of the future.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2018; ©2018 |
| Publication date | 2018; 2018 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Chew, Annabel Rong-Hui | |
|---|---|---|
| Degree supervisor | Salleo, Alberto | |
| Thesis advisor | Salleo, Alberto | |
| Thesis advisor | Reed, Evan J | |
| Thesis advisor | Toney, Michael Folsom | |
| Degree committee member | Reed, Evan J | |
| Degree committee member | Toney, Michael Folsom | |
| Associated with | Stanford University, Department of Materials Science and Engineering. |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Annabel Rong-Hui Chew. |
|---|---|
| Note | Submitted to the Department of Materials Science and Engineering. |
| Thesis | Thesis Ph.D. Stanford University 2018. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2018 by Annabel Rong-Hui Chew
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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