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Proceedings Paper

Increase the field-effect mobility of regioregular poly(3-hexylthiophene) by introducing fixed acceptor molecules
Author(s): Silvia Janietz; Dessislava Sainova; Armin Wedel
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Paper Abstract

It is well known of regioregular poly(3-hexylthiophene) (P3HT) to self-assemble on hydrophobic surfaces, because the regular arrangement of its side chains allows an efficient π-stacking of the conjugated backbones. This should be the reason for the very high reported field effect mobilities (0.2 cm2/Vs)1. We present an alternative approach to increase the field effect mobility and the transistor stability by introducing a strong acceptor dopant in the main chain of P3HT while preserving the regioregularity of the 3-hexylthiophene segments in the polymer chain. P3HTs with different contents of acceptor molecules which are fixed linked in the main chain of the polymer, were synthesized using the McCullough Grignard metathesis method. As acceptor unit has been integrated 9-dicyanomethane-fluorene. The introduced dopant amount has been varied in order to obtain an optimum between the processability of the polymers and the resultant transistor performance. The utilized organic field effect transistor (OFET) substrates with SiO2 gate dielectric were always pre-treated with a silylating agent (HMDS) to facilitate the self-organization properties of the polymers by hydrophobization of the SiO2 surface. The optimized doped structures showed higher field effect mobility by one order of magnitude compared to the conventional P3HT, (μFE~9 x 10-3 cm2/V.s for the doped compound vs. μFE~5 x 10-4 cm2/V.s for P3HT), combined with a marked current modulation with ON/OFF ratio of ~ 7 x 103 and a better operational stability of the resultant OFET-devices.

Paper Details

Date Published: 18 October 2004
PDF: 8 pages
Proc. SPIE 5522, Organic Field-Effect Transistors III, (18 October 2004); doi: 10.1117/12.560345
Show Author Affiliations
Silvia Janietz, Fraunhofer-Institut fur Kurzzeitdynamik (Germany)
Dessislava Sainova, Fraunhofer-Institut fur Kurzzeitdynamik (Germany)
Armin Wedel, Fraunhofer-Institut fur Kurzzeitdynamik (Germany)

Published in SPIE Proceedings Vol. 5522:
Organic Field-Effect Transistors III
Ananth Dodabalapur, Editor(s)

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