scholarly journals Formation and Characterization of Copper Nanocube-Decorated Reduced Graphene Oxide Film

2017 ◽  
Vol 2017 ◽  
pp. 1-6
Author(s):  
M. Z. H. Khan ◽  
M. A. Rahman ◽  
P. Yasmin ◽  
F. K. Tareq ◽  
N. Yuta ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Indium Tin Oxide ◽  
Chemical Reduction ◽  
Device Fabrication ◽  
Simple Method ◽  
Force Microscopy ◽  
Reduced Graphene ◽  
Vis Spectroscopy ◽  
The Individual

In this study, we present a new approach for the formation and deposition of Cu nanocube-decorated reduced graphene oxide (rGO-CuNCs) nanosheet on indium tin oxide (ITO) electrode using very simple method. Cubic Cu nanocrystals have been successfully fabricated on rGO by a chemical reduction method at low temperature. The morphologies of the synthesized materials were characterized by ultraviolet-visible (UV-vis) spectroscopy, scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and atomic force microscopy (AFM). The as-formed CuNCs were found to be homogeneously and uniformly decorated on rGO nanosheets. We demonstrated that the individual rGO sheets can be readily reduced and decorated with CuNCs under a mild condition using L-ascorbic acid (L-AA). Such novel ITO/rGO-CuNCs represent promising platform for future device fabrication and electrocatalytic applications.

Ammonia Gas Sensor Based on Aniline Reduced Graphene Oxide

2013 ◽  
Vol 669 ◽  
pp. 79-84 ◽  
Author(s):  
Xiao Lu Huang ◽  
Nan Tao Hu ◽  
Yan Yan Wang ◽  
Ya Fei Zhang
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Gas Sensor ◽  
Chemical Reduction ◽  
Electrode Arrays ◽  
Ammonia Gas ◽  
Reduced Graphene ◽  
Vis Spectroscopy ◽  
Drop Drying

Here we demonstrate a promising gas sensor based on aniline reduced graphene oxide (RGO), which is fabricated through drop drying RGO nanosheets suspension between the electrode arrays to create conductive networks. RGO, as the sensing materials, which is prepared via the chemical reduction of graphene oxide (GO) by aniline, has been characterized by infrared spectroscopy, UV-Vis spectroscopy, transmittance electron microscopy and scanning electron microscopy. The sensing properties of RGO have also been studied, and the results show that RGO reduced from aniline (RGO-A) exhibits an excellent response to ammonia gas (NH3). Comparing with the RGO reduced from hydrazine (RGO-H) and polyaniline (PANI) nanofiber, the RGO-A exhibits a much better response to NH3 gas. The response of the sensor based on RGO-A to 50 ppm NH3 gas exhibits about 9.2 times and 3.5 times higher than those of the device based RGO-H and PANI nanofiber respectively. In addition, the RGO-A sensor exhibits an excellent repeatability and selectivity to NH3 gas. The oxidized aniline, i.e., polyaniline, which is attached on the surface of RGO sheets through π–π interaction, plays important roles in the final sensing performance of the device, and benefits for the application of the sensor in the field of NH3 gas detection.

scholarly journals Improved Hole Injection in Bulk Heterojunction (BHJ) Hybrid Solar Cells by Applying a Thermally Reduced Graphene Oxide Buffer Layer

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Alfian F. Madsuha ◽  
Chuyen Van Pham ◽  
Michael Eck ◽  
Martin Neukom ◽  
Michael Krueger
Keyword(s):  
Graphene Oxide ◽  
Solar Cells ◽  
Reduced Graphene Oxide ◽  
Indium Tin Oxide ◽  
Hole Transport ◽  
Band Alignment ◽  
Hybrid Solar Cells ◽  
Simple Method ◽  
Reduced Graphene ◽  
Charge Extraction

In this work, the utilization of graphene oxide (GO), reduced graphene oxide (rGO), and carbon nanotube (CNT) thin films as hole transport and electron-blocking layers in polymer/nanocrystal hybrid solar cells is demonstrated. A simple method has been used to modify the anode of hybrid solar cells by depositing these two solution-processable nanocarbon materials between poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) and transparent indium tin oxide (ITO) layers. Upon the use of an rGO interlayer, we found a substantial improvement in power conversion efficiency (PCE) from 2.5% to 3.2% due to a decrease in series resistance (Rs). This decrease has been obtained by a careful tuning of the reduction degree of rGO, inducing optimization of the energy band alignment at the solar cell anode. In addition, charge extraction by linearly increasing voltage (CELIV) measurements show an increase in light-induced charge extraction of ca. 50%. Finally, the utilization of rGO as replacement for PEDOT:PSS is also presented. The findings reported in this work demonstrate the excellent potential of rGO as an efficient hole transport material in hybrid solar cells.

Effect of Chemical Reduction Temperature on Optical Properties of Reduced Graphene Oxide (rGO) and its Potentials Supercapacitor Device

2017 ◽  
Vol 901 ◽  
pp. 55-61 ◽  
Author(s):  
Haris Suhendar ◽  
Ahmad Kusumaatmaja ◽  
Kuwat Triyana ◽  
Iman Santoso
Keyword(s):  
Optical Properties ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Chemical Reduction ◽  
Epoxy Group ◽  
Electrical Energy ◽  
Graphite Powder ◽  
Reduction Temperature ◽  
Reduced Graphene ◽  
Vis Spectroscopy

Reduced graphene oxide (rGO) has been successfully synthesized from graphite powder using Hummer’s Method. The epoxy group in GO structure was reduced by hydrazine 80 wt% at a temperature of 70o, 80o, and 90°C. The optical properties of produced rGO were characterized by using Uv-Vis and FTIR spectrometer. From Uv-Vis spectroscopy we observe that the absorbance of rGO decreased as increasing the reduction temperature. This is because the higher reduction temperature yields a high degree of rGO defect. The rGO produced at a reduction temperature of 70oC has very close similiraties absorbance spectrum with rGO produced by Sigma Aldrich Company. The Uv-Vis absorbance of rGO was used to calculated optical constant, and by using Kramers-Kronig relation we got refractive index values of rGO. The decreasing of absorbance may also stem out from the reducing of C=C bonding with sp2 hybridization due to the presence of energetic Hydrazine as indicated by the decrease of FTIR spectrum at ~1600 cm-1. Our produced rGO then used to fabricated the supercapacitor device with a mass of 0,03 gram using Polivinyl Alcohol (PVA) as a binder. From cyclic voltammetry measurement, we obtain the specific capacitance of our rGO-based supercapacitor is 2.45 F which is still in the category of supercapacitive although the optimization of rGO and PVA composition is still required. Our result shows the exciting potential of rGO based supercapacitor as electrical energy storage.

scholarly journals Back-to-Back Schottky Diode from Vacuum Filtered and Chemically Reduced Graphene Oxide

2018 ◽  
Vol 10 (3) ◽  
pp. 897
Author(s):  
Siti Nadiah Che Azmi ◽  
Shaharin Fadzli Abd Rahman ◽  
Abdul Manaf Hashim
Keyword(s):  
Ascorbic Acid ◽  
Graphene Oxide ◽  
Film Thickness ◽  
Reduced Graphene Oxide ◽  
Schottky Diode ◽  
Chemical Reduction ◽  
Process Condition ◽  
Reduction Process ◽  
Simple Method ◽  
Reduced Graphene

<span>This paper presents fabrication of reduced graphene oxide (rGO)/silicon (Si) back-to-back Schottky diode (BBSD) through graphene oxide (GO) thin film formation by vacuum filtration and chemical reduction of the film via ascorbic acid. In order to understand and assess the viability of these two processes, process condition and parameters were varied and analyzed. It was confirmed that the GO film thickness could be controlled by changing GO dispersion volume and concentration. Filtration of 200 ml of 0.4 ppm GO dispersion produced average film thickness of 53 nm. As for the reduction process, long duration was required to produce higher reduction degree. rGO film that underwent two times reduction at before and after transfer process with concentrated ascorbic acid gave the lowest sheet resistance of 3.58 MΩ/sq. In the final part of the paper, result of the BBSD device fabrication and current-voltage characterization were shown. The formed two rGO/Si Schottky junctions in the BBSD gave barrier height of 0.63 and 0.7 eV. The presented results confirmed the viability of fabricating rGO-based device using a simple method and without requirement of sophisticated equipment.</span>

scholarly journals A Facile and Green Synthesis of a MoO2-Reduced Graphene Oxide Aerogel for Energy Storage Devices

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 594 ◽  
Author(s):  
Mara Serrapede ◽  
Marco Fontana ◽  
Arnaud Gigot ◽  
Marco Armandi ◽  
Glenda Biasotto ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Chemical Reduction ◽  
Low Cost ◽  
Xps Analysis ◽  
3D Scaffold ◽  
Energy Storage Devices ◽  
Reduced Graphene

A simple, low cost, and “green” method of hydrothermal synthesis, based on the addition of l-ascorbic acid (l-AA) as a reducing agent, is presented in order to obtain reduced graphene oxide (rGO) and hybrid rGO-MoO2 aerogels for the fabrication of supercapacitors. The resulting high degree of chemical reduction of graphene oxide (GO), confirmed by X-Ray Photoelectron Spectroscopy (XPS) analysis, is shown to produce a better electrical double layer (EDL) capacitance, as shown by cyclic voltammetric (CV) measurements. Moreover, a good reduction yield of the carbonaceous 3D-scaffold seems to be achievable even when the precursor of molybdenum oxide is added to the pristine slurry in order to get the hybrid rGO-MoO2 compound. The pseudocapacitance contribution from the resulting embedded MoO2 microstructures, was then studied by means of CV and electrochemical impedance spectroscopy (EIS). The oxidation state of the molybdenum in the MoO2 particles embedded in the rGO aerogel was deeply studied by means of XPS analysis and valuable information on the electrochemical behavior, according to the involved redox reactions, was obtained. Finally, the increased stability of the aerogels prepared with l-AA, after charge-discharge cycling, was demonstrated and confirmed by means of Field Emission Scanning Electron Microscopy (FESEM) characterization.

Chemically reduced graphene oxide-coated knitted fabric imparted conductivity and outstanding hydrophobicity

2021 ◽  
pp. 004051752199547
Author(s):  
Min Hou ◽  
Xinghua Hong ◽  
Yanjun Tang ◽  
Zimin Jin ◽  
Chengyan Zhu ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Chemical Reduction ◽  
Knitted Fabric ◽  
Mesh Structure ◽  
Reduced Graphene ◽  
Chemically Reduced Graphene Oxide ◽  
Modified Hummers Method

Functionalized knitted fabric, as a kind of flexible, wearable, and waterproof material capable of conductivity, sensitivity and outstanding hydrophobicity, is valuable for multi-field applications. Herein, the reduced graphene oxide (RGO)-coated knitted fabric (polyester/spandex blended) is prepared, which involves the use of graphite oxide (GO) by modified Hummers method and in-situ chemical reduction with hydrazine hydrate. The treated fabric exhibits a high electrical conductivity (202.09 S/cm) and an outstanding hydrophobicity (140°). The outstanding hydrophobicity is associated with the morphology of the fabric and fiber with reference to pseudo-infiltration. These properties can withstand repeated bending and washing without serious deterioration, maintaining good electrical conductivity (35.70 S/cm) and contact angle (119.39°) after eight standard washing cycles. The material, which has RGO architecture and continuous loop mesh structure, can find wide use in smart garment applications.

scholarly journals Electrochemical Impedance Characterization of Cell Growth on Reduced Graphene Oxide–Gold Nanoparticles Electrodeposited on Indium Tin Oxide Electrodes

2019 ◽  
Vol 9 (2) ◽  
pp. 326 ◽  
Author(s):  
Somasekhar Chinnadayyala ◽  
Jinsoo Park ◽  
Yonghyun Choi ◽  
Jae-Hee Han ◽  
Ajay Yagati ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Graphene Oxide ◽  
Cell Growth ◽  
Reduced Graphene Oxide ◽  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Electrochemical Impedance ◽  
Hek293 Cells ◽  
Ito Electrode ◽  
Reduced Graphene

The improved binding ability of graphene–nanoparticle composites to proteins or molecules can be utilized to develop new cell-based assays. In this study, we fabricated reduced graphene oxide–gold nanoparticles (rGO-AuNP) electrodeposited onto a transparent indium tin oxide (ITO) electrode and investigated the feasibility of the electrochemical impedance monitoring of cell growth. The electrodeposition of rGO–AuNP on the ITO was optically and electrochemically characterized in comparison to bare, rGO-, and AuNP-deposited electrodes. The cell growth on the rGO–AuNP/ITO electrode was analyzed via electrochemical impedance measurement together with the microscopic observation of HEK293 cells transfected with a green fluorescent protein expression vector. The results showed that rGO–AuNP was biocompatible and induced an increase in cell adherence to the electrode when compared to the bare, AuNP-, or rGO-deposited ITO electrode. At 54 h cultivation, the average and standard deviation of the saturated normalized impedance magnitude of the rGO–AuNP/ITO electrode was 3.44 ± 0.16, while the value of the bare, AuNP-, and rGO-deposited ITO electrode was 2.48 ± 0.15, 2.61 ± 0.18, and 3.01 ± 0.25, respectively. The higher saturated value of the cell impedance indicates that the impedimetric cell-based assay has a broader measurement range. Thus, the rGO–AuNP/ITO electrode can be utilized for label-free and real-time impedimetric cell-based assays with wider dynamic range.

scholarly journals Synthesis and Characterization of Reduced Graphene Oxide (rGO) Started from Graphene Oxide (GO) Using the Tour Method with Different Parameters

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Adere Tarekegne Habte ◽  
Delele Worku Ayele
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Potassium Permanganate ◽  
Chemical Reduction ◽  
Volume Ratio ◽  
Graphite Powder ◽  
Green Approach ◽  
Synthesis Strategy ◽  
Reduced Graphene ◽  
Diffraction Patterns

A new approach to synthesize graphene is oxidizing graphite powder with a mixture of H2SO4/H3PO4 acids and potassium permanganate. Parameters such as reaction time, reaction temperature, and amount of concentration were varied to study the degree of oxidation of graphite to graphene oxide. Currently, an improved method for the preparation of graphene oxide was the most common one. A mixture of H2SO4/H3PO4 (9 : 1 volume ratio) instead of only H2SO4 resulted in increased hydrophilic and oxidized GO without the emission of toxic gas, which differs from the traditional Hummers’ method. The graphene oxide (GO) was converted to reduced graphene oxide (rGO) by chemical reduction using ascorbic acid as the reducing agent. The GO and rGO were characterized by UV-visible spectroscopy, FTIR spectroscopy, and X-ray diffraction patterns. The result showed that treating graphite powder with potassium permanganate (1 : 9) and a mixture of concentrated H2SO4/H3PO4 acids at 50°C for 12 hours resulted in a better oxidation degree. The designed synthesis strategy could be easily controlled and is an alternative green approach for the production of graphene oxide and reduced graphene oxide.

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