Effect of hydrothermal and chemical treatment on the optical and electrical properties of reduced graphene oxide deposited on ITO glass

Abstract

In this work, the effect of hydrothermal and chemical treatment on the optical and electrical properties of reduced graphene oxide (RGO) was investigated. Reduced graphene oxide was synthesized by both hydrothermal route using a locally fabricated Teflon lined autoclave and chemical method using hydrazine monohydrate. The thin film was obtained by depositing RGO on Indium Tin Oxide (ITO) glass via spray pyrolysis technique. In RGO hydrothermal, the Raman spectroscopy analysis showed greater restoration of the conjugated networks in graphene sheet. The optical transmittance of RGO hydrothermal and RGO hydrazine decreased after the reduction methods unlike in highly oxidized graphene oxide (HOGO) where eighty percent transmittance was observed at 600 nm and above. For RGO hydrothermal and RGO hydrazine; the optical analysis gave an energy band gap value of 2.1 eV and 2.4 eV respectively, while the resistivity were calculated to be 0.3 Ω m and 0.09 Ω m respectively. This research showed a correlation between the band gap value of RGO and the electrical conductivity. This finding can improve the functionality of RGO as sensing materials. The improved electrical and optical properties of RGO hydrothermal makes it suitable in fiber-optic and opto-electronic applications.

Comparative investigation of gas sensing performance of liquefied petroleum gas using green reduced graphene oxide-based sensors

“…This is a pointer to an increased restoration of sp 2 carbon caused by greater reduction of GO and thus a rearrangement of atoms. 27,34 Also, the n-p* peak of MRGO 12H red shied to 357.85 nm which is much higher than the values for NRGO and PRGO. For all the orbitals, MRGO 12H showed a greater red shi in wavelength compared to PRGO and NRGO as previously reported.…”

“…The morphology shows that it is well refined and smoother in variants of GOs reduced by methionine unlike previously reported rGO reduced by neem and pumpkin extract 30 and those reduced by hydrazine and hydrothermal method. 27…”

“…Obtaining rGO based sensors by reduction using green and environmental approach is beneficial to the environment and cost effective. This further removes the possibility of the contamination of the sensors with chemicals used during reduction 27 thus reducing the recovery time of the sensors. Also, for thermally reduced graphene oxide utilized in sensor applications, the high temperature utilized during the reduction process results in irreproducibility of the sensors and longer recovery times.…”

Inhibition of cold‐welding and adhesive wear occurring on surface of the 6061 aluminum alloy by graphene oxide/polyethylene glycol composite water‐based lubricant

“…Figure 2B shows the FT‐IR spectra of the single GO and GO/PEG composite. The single GO has a high intensity and broad absorption peak at 3215 cm −1 indicating OH stretching; the absorption peak at 1736 cm −1 indicating carbonyl C═O stretching; the absorption peak at 1625 cm −1 indicating aromatic ring C═C stretching; and the absorption peaks at 1435, 1059, and 985 cm −1 for FT‐IR absorption peaks indicating CO stretching, COH stretching, epoxy COC stretching, and CO stretching, respectively 30–35 . The GO/PEG composite shows strong FT‐IR absorption peaks at 3421, 2889, 1488, 1343, 1109, 962, and 842 cm −1 .…”

“…Figure 2C shows the Raman spectral images of a single GO and GO/PEG composite. The Raman spectral images of the single GO show D‐band at 1342.08 cm −1 and G‐band at 1597.75 cm −1 , respectively, with the D‐band representing edges, defects, and disordered sp 3 hybridized carbon and the G‐band representing vibrations of ordered sp 2 hybridized atoms 29,32–35 . The energy ratio of the D‐band to the G‐band (I D /I G ) is usually used to indicate the extent of defects in carbon materials, with a higher value of I D /I G indicating a greater extent of defects.…”