Tight Binding Model of Charge Localization and Excitons in Semiconducting Polymers
Open Access
- Author:
- Bombile, Joel
- Graduate Program:
- Chemical Engineering
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- November 13, 2018
- Committee Members:
- Scott Thomas Milner, Dissertation Advisor/Co-Advisor
Michael John Janik, Committee Chair/Co-Chair
Enrique Daniel Gomez, Committee Member
Ismaila Dabo, Committee Member
John B Asbury, Outside Member
Michael John Janik, Dissertation Advisor/Co-Advisor
Scott Thomas Milner, Committee Chair/Co-Chair - Keywords:
- Organic electronics
Semiconducting polymers
Tight binding
Charge localization
Polaron
Exciton
Charge Transport - Abstract:
- Semiconducting polymers are being actively investigated in both academic and industrial research as alternative materials for various electronic devices. Their ease of processing and plastic-like mechanical properties are set to revolutionize the application of these electronic devices. However the electronic properties of polymers still lag behind their inorganic counterparts, owing to a limited understanding of the electronic processes in the these materials. The soft nature of polymers, which is responsible for their attractive mechanical properties, limits the use of the computational quantum mechanical methods that have been widely successful in guiding the design and optimization of inorganic materials, for their study. A major factor is the computational expense involved in effectively modeling the electronic properties of semiconducting polymers using these methods. This dissertation employs a semi-empirical approach based on the tight binding method to cost-effectively describe the localization of electronic states by quenched structural disorder, polaron formation, and exciton binding in semiconducting polymers. These phenomena or processes impact many electronic properties that determine the performance of electronic devices based on these materials. This is illustrated for the cases of the optical absorption spectrum, exciton dissociation for charge generation in photovoltaic devices, and charge transport. The tight binding models, carefully parameterized using first-principal quantum mechanical calculations, provide both qualitative and quantitative insight into the modeled properties, with a connection to the material structure.