DC conduction in electrochemically synthesized polypyrrole films

Date

1998-01-01

Author

Kaynak, A

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

127
views

0
downloads

DC conductivity measurements were performed by modified four-probe rig on electrochemically synthesized polypyrrole films at a temperature range of -30 degrees C to 120 degrees C. Conductivity increased with temperature. The temperature dependence of conductivity was very high for lightly doped polymers, decreasing as the doping level increased. The model used to describe the conduction process was the conduction model originally developed for amorphous silicon by Mott and Davis. When applied to conducting polymers, it assumes that electron transport originates from localized or fixed states within the polymer chain. The charge transfer between the chains takes place by hopping, referred to as phonon-assisted hopping, between two localized states. Plots of DC conductivity versus temperature can be parametrized by Mott's Variable Range Hopping conduction model. The DC conductivity of polypyrrole films doped from light to intermediate levels with p-toluene sulphonic acid were measured in the temperature range of 77K to 300K. The localization length of localized electrons was assumed to be 3 Angstrom which is approximately equal to the length of the pyrrole monomer. Mott parameters of polypyrrole films doped with p-TS were evaluated at 300K and 10K. Results were found to be consistent with the Mott's requirement that alpha R >> 1. Theoretical values of alpha and N(E-F) have been determined at approximately 10(8) cm(-1) and 10(19)-10(20) cm(-3) eV(-1), respectively. Hence according to Mott parameters determined by the experimental data for the p-TS doped polypyrrole samples. Mott parameters are seen to have a better agreement with those expected from disordered systems, particularly for lightly doped samples, indicating the suitability of Mott's model to these samples. The average hopping distance R decreased from 16 Angstrom to 4.4 Angstrom with the increase in the doping level from 0.006 M to 0.03 M at 300K, whereas at 10K, R decreased from 37 Angstrom to 10 Angstrom over the same dopant range.

URI

https://hdl.handle.net/11511/63726

Journal

TURKISH JOURNAL OF CHEMISTRY

Collections

Department of Engineering Sciences, Article

Suggestions

OpenMETU
Core

Current transport mechanisms in low resistive CdS thin films Günal, İbrahim; Parlak, Mehmet (Springer Science and Business Media LLC, 1997-02-01) The current transport mechanisms in polycrystalline CdS thin films have been studied as a function of temperature over the temperature range 20-230 K. Conductivity data for the high temperature region has been analysed using Seto's model of thermionic emission. At intermediate temperatures it was found that thermionic emission and tunnelling of carriers through the potential barrier both contribute to the conductivity. Below 100 K Mott's hopping process appears to be the predominant conduction mechanism.
Gradient-based optimization of micro-scale pressurized volumetric receiver geometry and flow rate Akba, Tufan; Baker, Derek Keıth; Mengüç, M. Pınar (2023-02-01) This study focuses on the design optimization of a micro-scale pressurized volumetric receiver by changing geometry and flow rate constrained by the volume, outlet air temperature, and outer surface temperature. The pressurized volumetric receiver model is replicated from an existing model, which assumes constant air pressure and neglects the convection loss from the cavity. The existing model is revised from a solver to a design optimizer. The replicated model is restructured using OpenMDAO (Open-source Mu...
Annealing Effect on Dark Electrical Conductivity and Photoconductivity of Ga-In-Se Thin Films IŞIK, MEHMET; Güllü, Hasan Hüseyin (2018-05-01) Dark-conductivity and photoconductivity properties of thermally evaporated Ga-In-Se (GIS) thin films were investigated in the temperature range of 80-430 K. All measurements were performed on as-grown and annealed GIS thin films at 300 and 400 degrees C to get information about the effect of the annealing temperature on the conductivity properties. Room temperature conductivity was obtained as 1.8 x 10(-8) Omega(-1) cm(-1) for as-grown films and increased to 3.6 x 10(-4) Omega(-1) cm(-1) for annealed films ...
Temperature effect on dark electrical conductivity, Hall coefficient, space charge limited current and photoconductivity of TlGaS2 single crystals Qasrawi, AF; Hasanlı, Nızamı (IOP Publishing, 2005-05-01) The dark electrical conductivity, Hall coefficient, space charge limited current, and illumination and temperature dependences of the photocurrent of TIGaS2 single crystals in the temperature regions of 100-350, 200-350, 200-290 and 100-350 K, respectively, have been measured and analysed. The Hall coefficient measurements revealed the extrinsic type of conduction with conductivity-type conversion from p- to n-type at a critical temperature of 315 K. The temperature dependence of the dark electrical conduct...
Photo-transferred thermoluminescence of shallow traps in beta-irradiated BeO ceramics Isik, M.; Bulur, Enver; Hasanlı, Nızamı (2017-07-01) Photo-transferred thermoluminescence signals from beryllium oxide (BeO) ceramics were measured in the low temperature range of 10-300 K. Samples irradiated at room temperature using a Sr-90/Y-19 beta source were cooled down to 10 K and trapped charges were photo-transferred at this low temperature using the light from a high power blue LED emitting at similar to 470 nm (2.6 eV). Thermoluminescence glow curve recorded at 0.2 K/s heating rate exhibited three peaks around 90, 160 and 185 K. The analyses of the...

Citation Formats

A. Kaynak, “DC conduction in electrochemically synthesized polypyrrole films,” TURKISH JOURNAL OF CHEMISTRY, pp. 81–85, 1998, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/63726.