Effect of high-pressure fluorination on electrical properties of multi-walled carbon nanotubes sheet

¹ Machine Tool Industry, Materials Technology and Engineering Production Sub Department, K. Satbayev Kazakh National Technical University, Kazakhstan
² Nanotech Institute, University of Texas at Dallas, USA
³ Institut de Recherche en Communications et Cybernétique de Nantes (IRCCYN), Ecole Centrale de Nantes, France

^a e-mail: ramakrishnan@irccyn.ec-nantes.fr

Received: 6 March 2015
Revised: 25 June 2015
Accepted: 30 June 2015
Published online: 3 November 2015

Abstract

High-pressure fluorination of multi-walled carbon nanotubes (MWNTs) sheet was performed at room temperature. This fluorine treatment increases the electrical conductivity of MWNTs sheet. In addition, low-temperature conductivity measurement data gives a good fit to variable-range hopping (VRH) model. Thus, VRH model was adopted to study and understand the increase in electrical conductivity. Estimation of the degree of disorder from the experimental data and VRH model indicate that degree of disorder of fluorinated multi-walled carbon nanotubes (FMWNTs) is higher than that of MWNTs. Higher degree of disorder of FMWNTs sheet substantiate the increase in electrical conductivity when compared to MWNTs. Scanning Electron Microscopy (SEM) and Raman analysis shows that change in structural disorder of FMWNTs network. Effect of fluorination on activation energy was also studied. The activation energy reduces with lower temperatures. The estimated values of temperature coefficient of resistance also show the increase in degree of disorder of FMWNTs. The change in electrical properties of FMWNTs is a much-needed requirement in the application of nano-electronics.