Superior Electronic and Dielectric Properties of Corrugated Electrochemically Reduced Graphene over Graphene Oxide Papers

Abstract

This work establishes that the frequency and temperature-dependent electronic and dielectric properties of electrochemically reduced graphene (ERGO) are higher than graphene oxide (GO) papers by 2 orders of magnitude. There is stronger polarization as a result of increased concentration of reduced clusters and thinning of graphene sheets in ERGO papers, first ever electrochemically reduced paper from GO. In GO, there is a greater dependence on frequency due to a higher percentage of interlayer O-H bonds. Dielectric permittivity increases with decreasing frequency due to stronger polarization and reduced conduction losses. At very high frequencies, greater conduction losses are responsible for lower values of dielectric permittivity of ERGO papers compared to GO papers. The "U" or "W" profile (σ vs T curves) of temperature dependent conductivity was due to thermally activated transport, residence time and ionic scattering of charge carriers. The recovery of conducting and dielectric properties at higher temperatures were due to the transition from graphene-ion-cloud to a graphene-air dielectric multi-nano-capacitor system. The latter had more sp2-carbon cluster concentration and increased electrical percolation supportive of band-like or variable range electron transport. Higher activation energies along ln σT vs T −1/2 plot are associated with delocalization of charge carriers from their potential wells, thermally activated carrier transport and frequency of the electronic field.

Effect of Electrolytic Medium on the Electrochemical Reduction of Graphene Oxide on Si(111) as Probed by XPS

“…In fact, GO has been applied in electronic gate dielectric materials, such as thin film transistors and resistive random-access memory, solar cells and biosensors. It was also reported to be a promising material in dentistry and tissue regeneration, as a biomaterial for interfacing cell imaging and drug delivery, and as an efficient cargo platform for cancer theranostics, phototherapy and bioimaging [ 22 , 23 , 24 , 25 , 26 , 27 , 28 ]. On the one hand, GO tackles some of the inherent disadvantages of pristine graphene (i.e., its high hydrophobicity, chemical inertness and lack of dispersibility in water), and on the other hand it exhibits some drawbacks (i.e., a low conductivity and amorphous structure) that hinder its broader applications.…”

Electrochemical Sensors Based on a Composite of Electrochemically Reduced Graphene Oxide and PEDOT:PSS for Hydrazine Detection

“…As a two-dimensional nanomaterial, electrochemically reduced graphene oxide (ErGO) has been intensively investigated in the fields of electroanalysis, − energy storage devices, − and electrocatalysis, − due to its excellent catalytic activity and chemical stability . In addition, poly­(3,4-ethylenedioxythiophene):poly­(styrenesulfonate) or PEDOT:PSS (previously used in uric acid sensors) is beneficial for enhancing the electrocatalytic activity and conductivity of the graphene oxide (GO) materials. − Therefore, in this study, we highlight the employment of the composite materials of ErGO with PEDOT:PSS deposited onto a glassy carbon electrode (GCE) for use as a hydrazine sensor.…”

All-Solid-State Supercapacitor with High Volumetric Energy for Flexible Application

“…3 Since these concerns are closely linked with charge storage mechanism and mechanical characteristics of electrode materials, many efforts are devoting to synthesize advanced active substances with large specific capacitance, high porosity and good flexibility. 4,5 Three-dimensional graphene monoliths including foam, hydrogel and aerogel have got a lot of attention very recently because the cross-linked graphene materials meet almost all of the requirements mentioned above. 6,7 These monoliths feature light weight, high flexibility, porous structure, electrical conductivity and large specific surface area.…”