Thermal and dielectric properties of multi-walled carbon nanotube-graphene oxide composite

Carbon based materials with a high dielectric performance and better thermal stability have great potential for many semiconductor device applications. In this paper, we report the preparation, thermal and dielectric properties of multi-walled carbon nanotube (MWCNT)-graphene oxide (GO) freestanding films. Different weight percentages of MWCNT-GO composite freestanding films were prepared using vacuum filtration method. Powder X-ray diffraction, scanning electron microscopy, Fourier transform infrared, micro Raman and UV-Vis-NIR spectroscopy studies revealed that the homogeneous dispersion of MWCNT in the GO matrix. Thermal stability of the MWCNT-GO composites linearly increases with increasing MWCNT content from 5 to 30 wt%. Our results show that the addition of 30 wt% MWCNT in GO increases the dielectric constants from 17 to 807 at 100 Hz which was even very high compared to conventional dielectric materials. The improvement of dielectric constant is attributed to the formation of microcapacitors by highly conductive MWCNT segregated by GO sheets. Meanwhile, the Cole-Cole plot elucidates the two semicircles for all samples representing the serial arrangement of two units that attributed to the contribution from the bulk composite and the interface region of the MWCNT-GO. The radius of arc in impedance spectra decreases with increasing MWCNT weight percentage indicating the higher electrical conductivity. The present results suggest that MWCNT-GO composite films are having promising application in the high frequency capacitors, high performance dielectric based electronic and energy storage devices.