Electronic Excitations and Metal-Insulator Transition inPoly(3-hexylthiophene) Organic Field-Effect Transistors
We carry out a comprehensive theoretical and experimentalstudy of charge injection in poly(3-hexylthiophene) (P3HT) to determinethe most likely scenario for metal-insulator transition in this system.Wecalculate the optical-absorption frequencies corresponding to a polaronand a bipolaron lattice in P3HT. We also analyze the electronicexcitations for three possible scenarios under which a first- or asecond-order metal-insulator transition can occur in doped P3HT. Thesetheoretical scenarios are compared with data from infrared absorptionspectroscopy on P3HT thin-film field-effect transistors (FETs). Ourmeasurements and theoretical predictions suggest that charge-inducedlocalized states in P3HT FETs are bipolarons and that the highest dopinglevel achieved in our experiments approaches that required for afirst-order metal-insulator transition.
- Research Organization:
- COLLABORATION - UC SanDiego
- DOE Contract Number:
- DE-AC02-05CH11231; NSF:NSF-0438018
- OSTI ID:
- 926299
- Report Number(s):
- LBNL-62717; R&D Project: 458121; BnR: KC0204016; TRN: US0803172
- Journal Information:
- Physical Review B, Vol. 75; Related Information: Journal Publication Date: January 5,2007
- Country of Publication:
- United States
- Language:
- English
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