Probing disorder and transport properties in polypyrrole thin-film devices by impedance and Raman spectroscopy

Varade, Vaibhav and Honnavar, Gajanan V and Anjaneyulu, P and Ramesh, KP and Menon, Reghu (2013) Probing disorder and transport properties in polypyrrole thin-film devices by impedance and Raman spectroscopy. In: Journal of Physics D: Applied Physics, 46 (36). 365306_1-365306_8.

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Abstract

In the present study, impedance and Raman spectroscopy are adopted to probe the nature and extent of disorder to correlate with transport properties in doped polypyrrole (PPy) thin-film devices, synthesized electrochemically at different temperatures. A comparative study of the impedance spectroscopy is performed on PPy devices by both experimental and simulation approach with varying extent of disorder. The impedance measurements of PPy devices are well described by introducing a constant phase element (CPE) (Q) in modified RQ circuit, which accounts for frequency dependence of dielectric response. However, for the PPy grown at lower temperature, an equivalent circuit consisting of two such RQ elements in series is used for successful modelling of the impedance results, which accounts for the depletion region near the electrode. Raman spectroscopy and the de-convoluted spectra are successfully studied to probe the variation in C=C bond stretching and distribution of conjugation length, which relates to disorder in PPy films and the interpretation is well correlated to the impedance results.

Item Type:	Journal Article
Publication:	Journal of Physics D: Applied Physics
Publisher:	IOP Publishing Ltd
Additional Information:	Copyright of this article belongs to IOP Publishing Ltd.
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	24 Sep 2013 06:25
Last Modified:	24 Sep 2013 06:25
URI:	http://eprints.iisc.ac.in/id/eprint/47420

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