Humidity dependent impedance response of graphene/carbon nanotubes composite

Graphene/Carbon Nanotubes (CNTs) composite is synthesized through sonication. The composite formation is verified by Scanning Electron Microscopy (SEM), Raman Spectroscopy, Fourier Transform Infrared Spectroscopy (FT-IR) and UV-vis Spectroscopy. SEM shows the formation of bridging CNTs and multilaye...

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Bibliographic Details
Published in:Materials research express 2018-09, Vol.5 (9), p.95028
Main Authors: Nawab, Adil, Murtaza, Imran, karimov, Khasan S, Ahmad, Naeem, Sajjad, Muhammad
Format: Article
Language:English
Subjects:
graphene/CNT composite
humidity sensing mechanism
impedance spectroscopy
Schottky junction effect
simulation
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Summary:Graphene/Carbon Nanotubes (CNTs) composite is synthesized through sonication. The composite formation is verified by Scanning Electron Microscopy (SEM), Raman Spectroscopy, Fourier Transform Infrared Spectroscopy (FT-IR) and UV-vis Spectroscopy. SEM shows the formation of bridging CNTs and multilayer capacitor configuration of the composite, whereas FT-IR confirms the functionalization of the composite. To understand the mechanism of humidity interaction with the composite and charge transport through the humidity layer, the electrical investigation is performed through impedance spectroscopy. Bode plot, Nyquist plot, real impedance and imaginary impedance are plotted versus frequency range of 10 Hz to 10 KHz at different relative humidity values varying from 50% to 95%. The results show the hopping of H+ ions at lower humidity and diffusion of H+ ions at higher humidity. The equivalent circuits are proposed and simulated for the lowest and highest humidity values. Simulated circuits indicate the existence of finite length diffusion Warburg element. Schottky junction effect at high and low humidity is also elaborated.
ISSN:2053-1591
2053-1591
DOI:10.1088/2053-1591/aad854