DC-bias effect on dielectric properties of multiwalled carbon nanotubes SDBS/PEDOT:PSS nanocomposites

Abstract

Multiwalled carbon nanotubes (MWCNTs) dispersed in sodium dodecylbenzenesulfonate (SDBS) then mixed with poly (3, 4-ethylenedioxythiophen)/ poly (4-styrene-sulfonate) (PEDOT:PSS) nanocomposites containing MWCNTs content between 0.025 wt.% and 0.1 wt.% were prepared and deposited on a flexible thin substrate (Kapton HN) using the drop casting technique. Alternating current (AC) electrical properties of thin films were investigated using a complex impedance analyzer over a wide range of frequency from 40 Hz to 110 MHz. The complex impedance responses indicate that DC-bias plays a crucial role in the complex impedance mechanism of MWCNT:SDBS/ PEDOT:PSS nanocomposites. It was found that the DC-bias leads to increase of conductivity of the nanocomposite due to the formation of additional conducting paths within the nanocomposite. It was also found that the DC-bias is more effective on the conduction mechanism of nanocomposite at low MWCNTs content. Furthermore, the dielectric constant of nanocomposite increases with the DC-bias due to enhancement of conducting electrons release in the nanocomposite. The bode diagram of nanocomposite containing 0.025 wt.% MWCNTs shows that the DC-bias has also influence on the relaxation mechanism of nanocomposite and the applicable DC-bias voltage value is limited and it is proportional to MWCNT concentration of nanocomposite.