The peculiar electrical response of liquid crystal-carbon nanotube systems as seen by impedance spectroscopy

García García, Amanda and Vergaz, Ricardo and Algorri Genaro, José Francisco and Geday, Morten Andreas and Otón Sánchez, José Manuel (2015). The peculiar electrical response of liquid crystal-carbon nanotube systems as seen by impedance spectroscopy. "Journal of Physics D: Applied Physics", v. 48 (n. 37); pp. 1-8. ISSN 0022-3727. https://doi.org/10.1088/0022-3727/48/37/375302.

Description

Title: The peculiar electrical response of liquid crystal-carbon nanotube systems as seen by impedance spectroscopy
Author/s:
  • García García, Amanda
  • Vergaz, Ricardo
  • Algorri Genaro, José Francisco
  • Geday, Morten Andreas
  • Otón Sánchez, José Manuel
Item Type: Article
Título de Revista/Publicación: Journal of Physics D: Applied Physics
Date: August 2015
Volume: 48
Subjects:
Freetext Keywords: Impedance spectroscopy, carbon nanotube, liquid crystal, electric equivalent circuit, electrical response
Faculty: E.T.S.I. Telecomunicación (UPM)
Department: Tecnología Fotónica y Bioingeniería
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Abstract

Conductive nanoparticles, especially elongated ones such as carbon nanotubes, dramatically modify the electrical behavior of liquid crystal cells. These nanoparticles are known to reorient with liquid crystals in electric fields, causing significant variations of conductivity at minute concentrations of tens or hundreds ppm. The above notwithstanding, impedance spectroscopy of doped cells in the frequency range customarily employed by liquid crystal devices, 100 Hz?10 kHz, shows a relatively simple resistor/capacitor response where the components of the cell can be univocally assigned to single components of the electrical equivalent circuit. However, widening the frequency range up to 1 MHz or beyond reveals a complex behavior that cannot be explained with the same simple EEC. Moreover, the system impedance varies with the application of electric fields, their effect remaining after removing the field. Carbon nanotubes are reoriented together with liquid crystal reorientation when applying voltage, but barely reoriented back upon liquid crystal relaxation once the voltage is removed. Results demonstrate a remarkable variation in the impedance of the dielectric blend formed by liquid crystal and carbon nanotubes, the irreversible orientation of the carbon nanotubes and possible permanent contacts between electrodes.

Funding Projects

TypeCodeAcronymLeaderTitle
Madrid Regional GovernmentS2013/ MIT-2790UnspecifiedUnspecifiedUnspecified
Government of SpainTEC2013-47342-C2UnspecifiedUnspecifiedUnspecified

More information

Item ID: 40704
DC Identifier: http://oa.upm.es/40704/
OAI Identifier: oai:oa.upm.es:40704
DOI: 10.1088/0022-3727/48/37/375302
Official URL: http://iopscience.iop.org/article/10.1088/0022-3727/48/37/375302/meta
Deposited by: Memoria Investigacion
Deposited on: 06 Jun 2016 18:50
Last Modified: 01 Sep 2016 22:30
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