Doping Of Semiconducting Polymers For Electronic Applications

Open Access
Author:
Jones, David Hamilton
Graduate Program:
Materials Science and Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
July 17, 2014
Committee Members:
  • Michael Anthony Hickner, Thesis Advisor
  • Enrique Daniel Gomez, Thesis Advisor
  • Noel Christopher Giebink, Thesis Advisor
Keywords:
  • Organic electronics
  • P3HT
  • OFET
  • Doping
Abstract:
One branch of modern electronics requires avoiding the high processing costs associated with inorganic semiconductors in order to create novel low-cost, mechanically flexible, and low-profile devices for the next generation of consumer devices. Organic semiconductors can be doped to improve their charge mobility and carrier density towards creating better polymer-based photovoltaics, organic thin-film transistors, and organic light-emitting diodes. Dopants offer one route to improved device performance, but the specific interactions between the dopant molecule and the semiconductor must be designed for the desired function. This work explores the effects of sulfonic acid groups on the behavior of the common organic semiconductor poly-(3-hexylthiophene) (P3HT). P3HT was chosen for its ubiquitous use in photovoltaics and other organic electronic applications. The doping of P3HT by sulfonic acid-containing moieties was explored initially as a method to replace the poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) electron blocking later at the photovoltaic transparent indium tin oxide electrode. Measurements of doped thiophene-based polymers were conducted in organic thin-film transistor geometries to measure the charge carrier densities. Additionally, spectroscopic evidence of doping complemented the transistor and photovoltaic studies. This work explores the extent to which P3HT can be doped at the highest density and how it may be used in modern organic electronics such as transistors, photovoltaics, and light-emitting diodes.