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Lookup NU author(s): Professor Mark GeogheganORCiD
This is the authors' accepted manuscript of an article that has been published in its final definitive form by American Chemical Society, 2016.
For re-use rights please refer to the publisher's terms and conditions.
© 2016 American Chemical Society.Electrolyte-gated organic field-effect transistors (EGOFETs), based on ultrathin pentacene films on quartz, were operated with electrolyte solutions whose pH was systematically changed. Transistor parameters exhibit nonmonotonic variation versus pH, which cannot be accounted for by capacitive coupling through the Debye-Helmholtz layer. The data were fitted with an analytical model of the accumulated charge in the EGOFET, where Langmuir adsorption was introduced to describe the pH-dependent charge buildup at the quartz surface. The model provides an excellent fit to the threshold voltage and transfer characteristics as a function of the pH, which demonstrates that quartz acts as a second gate controlled by pH and is mostly effective from neutral to alkaline pH. The effective capacitance of the device is always greater than the capacitance of the electrolyte, thus highlighting the role of the substrate as an important active element for amplification of the transistor response.
Author(s): Di Lauro M, Casalini S, Berto M, Campana A, Cramer T, Murgia M, Geoghegan M, Bortolotti CA, Biscarini F
Publication type: Article
Publication status: Published
Journal: ACS Applied Materials and Interfaces
Print publication date: 23/11/2016
Online publication date: 11/11/2016
Acceptance date: 22/09/2016
Date deposited: 21/01/2021
ISSN (print): 1944-8244
ISSN (electronic): 1944-8252
Publisher: American Chemical Society
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