Broadband dielectric behavior of the multiwall carbon nanotube-bismuth silicate glass-nanocomposites

Multiwall carbon nanotube-bismuth silicate (BS) glass-nanocomposites were successfully synthesized by simple colloidal method. Systematic investigation of the dielectric impedance has been carried out on the x-MWCNT-yBi2O3-(100-y)SiO2 (x = 1, 2.5, 5, 10, 20, MWCNT = Multiwall carbon nanotube and y = 70, 60 and 50) glass-nanocomposite in the frequency range from 315 mHz to 10 MHz and temperature range from room temperature to 340 °C. We observed percolation threshold is taking place in between 1 and 2.5 wt% of MWCNT in BS glass. The conductivity is frequency dependent before percolation threshold and thereafter it remains constant. At the same time, a broad band type dielectric behavior is noticed in our MWCNT-BS glass-nanocomposites where dielectric parameters can be tuned from positive to negative by varying the concentration of MWCNT in BS glass. Based on our investigations, a possible model about the conductivity behavior of MWCNT-glass nanocomposites has been drawn. [Display omitted] •MWCNT-Bi2O3-SiO2 glass-nanocomposites are prepared by using colloidal method.•Glass-nanocomposites above percolation threshold shows metallic behavior.•Broadband dielectric value flips negative-positive-negative within 315 mHz–10 MHz.