Graphene Nanocomposite Film Research Articles

To investigate opulence of graphene in ZnO/graphene nanocomposites based dye sensitized solar cells

The study reports the application of ZnO–graphene (ZGR) nanocomposite films for Dye-sensitized solar cells (DSSCs) as photoanodes. These nanocomposites were prepared by incorporating different amount of graphene (0–1 wt%) in sol–gel routed ZnO nanoparticles. The presence of graphene in nanocomposite films was revealed by X-ray diffraction (XRD) that was further supported by Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive X-ray (EDX). The surface roughness value of these ZGR nanocomposite films was examined by Atomic Force Microscopy (AFM). The UV–Visible spectrum of the synthesized ZGR nanocomposite films was found to be shifted towards a longer wavelength region as compared to bare ZnO that ensured the formation of interfacial contact between ZnO and graphene. The enhanced absorption in the visible region of spectra is observed on incorporation of graphene in these ZGR nanocomposites. Significant increments in room temperature Photoluminescence (PL) intensity was attributed to the plasmonic effect of graphene. DSSCs were assembled with these ZGR nanocomposite photoanode films after tethering with N749 (black dye) and the effect of graphene concentration on their performance was investigated. The maximum power conversion efficiency obtained from these ZGR nanocomposites based DSSC has reached 3.17% that is 53% higher than that of bare ZnO based DSSC (2.07%).

Convenient approach to making nanocomposites based on a chitosan–poly(vinyl pyrrolidone) polymer matrix and a graphene nanofiller

ABSTRACTConducting, mechanically durable, elastic nanocomposite films were prepared with chitosan (CS) as the polymer matrix, graphene obtained from highly exfoliated graphite as the nanofiller, and poly(vinyl pyrrolidone) (PVP) as the stabilizer of the graphene sheets. The maximum graphene content in the composites without a loss of uniformity and other useful properties increased up to 4.0 wt %. The resulting composites were characterized by scanning electron microscopy, Raman spectroscopy, X‐ray diffraction analysis, mechanical testing, and electrical conductivity testing to determine the effects of the addition of graphene on the morphology and mechanical and electrical properties of the CS–PVP–graphene nanocomposite films. In this study, we took an approach to making nanocomposites from the perspectives of green chemistry, environmental protection, regenerative medicine, and low cost. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45038.

Low Cost, Large Area, Flexible Graphene Nanocomposite Films for Energy Harvesting Applications

In this paper, we report a robust and a low-cost spin coating approach for fabrication of large area flexible piezoelectric nanocomposite generator device for harvesting biomechanical motions. In order to develop the piezoelectric nanocomposite, ZnO and BaTiO3 were used as filler materials for realization of piezoelectric nanogenerator. Serial stretching and bending tests over these devices illustrated generation of maximum open-circuit voltage of ∼237 and ∼736 mV for ZnO and BaTiO3, respectively. Furthermore, we also demonstrated a 2 × enhancement in output voltage performance of nanogenerator by adding graphene platelets to these diphasic piezoelectric nanocomposite systems.

Synthesis and electrochemical studies of Ta – Graphene nanocomposite film modified platinum electrode

Tantalum/Reduced Graphene Oxide composite is presented in this work as an electrode material for capacitor application. Reduced graphene oxide material was synthesized by modified Hummer's method and Tantalum doped graphene oxide electrodes are fabricated by an electrophoretic deposition method. The physico-chemical properties of the as-synthesized materials are characterized by X-ray diffraction, N2 sorption analyses, Fourier Transform Infrared and Raman spectroscopic techniques. The structural details are elucidated from the scanning and transmission electron microscopic analyses. The X-ray diffraction results confirmed the structural integrity of graphene after the Ta doping process. Raman analysis confirmed the graphitic nature of graphene with a surface area of 281m2/g. The surface area of the tantalum doped composite decreased to 214m2/g due to the deposition of Ta ions onto the graphene surface. The Ta doped graphene composite exhibited comparatively higher capacitance value of 1420μF/cm2 than graphene (980μF/cm2), indicating that this composite can store more charge in comparison with graphene. This enhancement of capacitance with Ta doped graphene is thus found to be a good candidate for super/ultra capacitor applications

Bismuth-Activated Graphene Nanocomposite Modified Electrode for Electrochemical Determination of Trace Heavy Metals

Heavy metals, such as Pb2+, Cd2+, and Zn2+, cause major public-health concerns due to their high stability and bio-accumulation. These heavy metals affect several human organs even at very low concentrations. Accordingly, developing simple, robust and highly sensitive analytical methods for assessing environmental pollutants in soil, water, and air samples to improve the quality of environment and human life is very important. Graphene is an excellent nanomaterial for electrochemistry owing to its good electrical conductivity, low cost, excellent mechanical properties, and high specific surface area. To date, much research has been focused on their development for attractive applications in electroanalytical chemistry as a unique electrode material for manifolds. Moreover, chemical modification of graphene could further improve its electrochemical performance. The resultant activated graphene has a unique structure that makes it attractive as a potential material for the electrochemical determination of trace metal ions. In this work, we developed a facile method for the preparation of a new and enhanced sensing platform based on bismuth and activated graphene. The activated graphene was prepared through chemical activation of graphene oxide with KOH to create nanopores. The surface morphology of the bismuth-activated graphene nanocomposite film modified electrode was investigated by using scanning electron microscopy and transmission electron microscopy. The electrochemical properties of the nanocomposite electrode were evaluated to examine the effects of experimental variables, such as deposition potential, deposition time, bismuth concentration, and stirring speed during pre-concentration, on the determination of trace metal ions. The bismuth-activated graphene nanocomposite electrode was applied for the simultaneous determination of trace zinc, cadmium, and lead by differential pulse anodic stripping voltammetry. The composite film integrates the unique properties of activated graphene and the advantages of bismuth electrodes, leading to enhanced sensitivity towards trace metal ions, especially zinc. The appearance of a zinc stripping peak reveals its superior sensitivity as compared to previous bismuth electrodes. The bismuth-activated graphene nanocomposite was also used as an electrode material for the sensitive determination of metal ions in a real sample. The limits of detection achieved are much lower than the guideline for drinking water quality provided by the World Health Organization. Thus, the proposed method facilitates the monitoring of trace heavy metals and can be expanded to detect other environmental pollutants.

Polyaniline/Graphene nanocomposite coatings on copper: Electropolymerization, characterization, and evaluation of corrosion protection performance

Polyaniline–graphene nanocomposite film was electrochemically deposited by cyclic voltammetry on copper electrode. The corrosion resistance of polyaniline–graphene nanocomposite covered copper substrates was estimated using potentiodynamic polarization and electrochemical impedance spectroscopy techniques in 5000ppm NaCl aqueous solution at room temperature. Potentiodynamic Polarization results show that corrosion potentials shift to anodic regions in the presence of polyaniline–graphene nanocomposite compared to the blank solution. The electrochemical measurements, also, indicated that the inhibition efficiency for polyaniline-graphene nanocomposite is 98%.

An Overview: Recent Development of Titanium Dioxide Loaded Graphene Nanocomposite Film for Solar Application

Recent studies have indicated that graphene is a relatively novel material with unique properties that could apply in solar-based application, such as quantum dot solar cells (QDSSCs), dye-sensitized solar cells (DSSCs), and perovskite solar cell (MSSCs). Graphene film is considered to be an ideal two-dimensional catalytic support due to its excellent electrical and thermal conductivity, mechanical strength, large surface area and incredibly high mobility of charge carriers. Lately, continuous efforts have been exerted to further improve the graphene textural and electronic properties by loading an optimum content of TiO2 for high efficiency solar-based application. In this review paper, an introduction of graphene / TiO2-graphene film, mechanism of formation, synthesis method, and potential solar applications are reviewed in details. Keywords: Graphene, TiO2-graphene, solar cells, catalytic support.

Exploring resistive switching in poly(4-vinylphenol)–graphene nano-composite films

In this study the organic resistive switching devices having sandwich structure of indium tin oxide (ITO)-coated glass/poly(4-vinylphenol) (PVP)–graphene composite/silver (Ag) were fabricated and characterized. The active layers were fabricated using blended, semiblend and layer-by-layer approaches, sandwiched between two electrodes. The film thicknesses of the active layers were measured to be about 200 nm. The surface morphology was characterized by field-emission scanning electron microscopy. Electrical current–voltage (I–V) analyses confirmed the memristive behavior of the sandwich devices. The effect of active layer fabrication approach was analyzed by comparing the resistive switching characteristics. The devices showed characteristic OFF to ON (high resistance to low resistance) transition at low voltages, when operated between ±2 V, characterized at 100 µA and 5 mA compliance currents. The memristive behavior of PVP–graphene active layer fabricated by blended approach showed more stability and robustness compared to non-blended approaches. The devices fabricated by blended approach exhibited a room temperature V–I hysteresis and ROFF/RON ≈ 5.

A Sensitive Amperometric Sensor for the Determination of Dopamine at Graphene and Bismuth Nanocomposite Film Modified Electrode

A Sensitive Amperometric Sensor for the Determination of Dopamine at Graphene and Bismuth Nanocomposite Film Modified Electrode

Photoelectrochemical sensing of catechol based on CdS-DNA-pristine graphene nanocomposite film

A photoelectrochemical (PEC) sensing platform was designed for catechol determination using CdS quantum dots (QDs), DNA and pristine graphene (PGR) nanocomposite film-modified electrode. In such a composite film-based PEC sensor, CdS QDs served as the photoelectric conversion element which produced photocurrent signal under visible light illumination; and DNA was designed as the biological recognition element which improved the PEC response of sensor toward catechol due to the interaction between DNA and catechol. To improve the electron transfer of the composite film, PGR with high electrical conductivity was doped, which significantly amplified the photocurrent signal of sensor. Based on such a CdS-DNA-PGR composite film-modified electrode, catechol showed a linear PEC response proportional to its concentration from 1.0×10−8 to 1.0×10−6molL−1. The detection limit (3S/N) was estimated to be 4.9×10−9molL−1. The developed PEC sensor was successfully applied to determine trace catechol in water samples.

A Novel Glucose Biosensor at Glucose Oxidase Immobilized Graphene and Bismuth Nanocomposite Film Modified Electrode

A Novel Glucose Biosensor at Glucose Oxidase Immobilized Graphene and Bismuth Nanocomposite Film Modified Electrode

A novel electrochemical aptasensor based on MWCNTs–BMIMPF6 and amino functionalized graphene nanocomposite films for determination of kanamycin

A simple and cost-efficient electrochemical aptasensor for sensitive and specific detection of kanamycin was reported.

A luminol electrochemiluminescence aptasensor based on glucose oxidase modified gold nanoparticles for measurement of platelet-derived growth factor BB

A sandwich-type luminol electrochemiluminescence (ECL) aptasensor for highly sensitive and selective detection of platelet-derived growth factor BB (PDGF-BB) is fabricated. For this proposed ECL aptasensor, a multilayered AuNPs-electrochemically reduced graphene (AuNPs-EG) nanocomposite film was formed on the GCE surface as the base of the aptasensor through a co-electrodeposition method. The AuNPs-EG composites possess high conductivity to promote the electron transfer at the electrode interface and good biocompatibility and large surface area to capture large amounts of primary aptamer (Apt1), thus amplifying the detection response. Moreover, glucose oxidase (GOD) functionalized AuNPs labeled secondary aptamer (GOD–Apt2–AuNPs) was designed as the signal probe for the sandwiched aptasensor. Enhanced sensitivity was obtained by in situ generation of H2O2 from reaction between GOD and glucose and the excellent catalytic behavior of AuNPs to the ECL of the luminol–H2O2 system. Under the optimal conditions, the as-prepared ECL aptasensor exhibited excellent analytical property for the detection of PDGF-BB in the range from 1.0×10–13 to 5.0×10−10molL−1 with a detection limit of 1.7×10–14molL−1 (S/N=3). The application of the present protocol was demonstrated by analyzing PDGF-BB in human serum and human urine samples with the recoveries from 85.0% to 110%.

An electrochemical aptasensor based on gold nanoparticles dotted graphene modified glassy carbon electrode for label-free detection of bisphenol A in milk samples

A simple and label-free electrochemical aptasensor for bisphenol A (BPA) determination was developed based on gold nanoparticles dotted graphene (GNPs/GR) nanocomposite film modified glassy carbon electrode (GCE). The electrochemical probe of ferricyanide was used to investigate the interactions between aptamer and BPA. The resulting GNPs/GR layer exhibited good current response for BPA detection. The highly conductive and biocompatible nanostructure of GNPs/GR nanocomposite was characterised by atomic force microscope (AFM), scanning electron microscopy (SEM) and cyclic voltammetry (CV). The peak current change (ΔI) of ferricyanide was linear with the concentration of BPA in the range from 0.01μM to 10μM with the detection limit of 5nM. The proposed aptasensor is rapid, convenient and low-cost for effective sensing of BPA. Particularly, the aptasensor was applied successfully to determine BPA in milk products, and the average recovery was 105%.

Electrochemical preparation of poly(methylene blue)/graphene nanocomposite thin films

Poly(methylene blue)/graphene nanocomposite thin films were prepared by electropolymerization of methylene blue in the presence of graphene which have been synthesized by two different methods of a chemical oxidation process and an electrochemical approach. Synthesized nanocomposite thin films were characterized by using cyclic voltammetry, UV–vis. absorption spectroscopy, powder X-ray diffraction, and scanning tunneling microscopy techniques. Electrocatalytical properties of prepared poly(methylene blue)/graphene nanocomposite films were compared toward electrochemical oxidation of nitrite. Under optimized conditions, electrocatalytical effect of nanocomposite films of chemically prepared graphene through electrochemical oxidation of nitrite was better than that of electrochemically prepared graphene.

Stretching of solution processed carbon nanotube and graphene nanocomposite films on rubber substrates

The fabrication and characterization of stretchable carbon nanotube and graphene nanocomposite electrodes on different rubber substrates is reported. Electrodes are fabricated at low temperatures using solution processable carbon nanomaterials. Rubber substrates are stretched while performing simultaneous electrical measurements for the electrodes. During 20% elongation of rubber substrates a 2- to 120-fold increase in the electrode resistance was observed, depending on the sample. The relative increase in the resistance with stretching was smaller in the case of graphene electrodes, whereas the resistance change during the elastomer relaxation was smaller in the case of carbon nanotube electrodes. Our results suggest that solution processed carbon nanomaterials on rubber substrates have potential for stretchable wiring and sensor applications.

Mild and novel electrochemical preparation of β-cyclodextrin/graphene nanocomposite film for super-sensitive sensing of quercetin

A mild and novel preparation tactics based on electrochemical techniques for the fabrication of electro-deposited graphene (E-GR) and polymerized β-cyclodextrin (P-βCD) nanocomposite film were developed. The structure and morphology of GR-based nanocomposite were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. Simultaneously, the electrochemical properties of this nanocomposite were characterized by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Based on the synergistic effect of E-GR and P-βCD, a super-sensitive electrochemical sensor for quercetin was successfully fabricated. Under optimum conditions, the determination range for quercetin was from 0.005 to 20µM with a low detection limit of 0.001µM (S/N=3). Moreover, this sensor also displays excellent sensitivity, fine reproducibility and stability. To further study the practical applicability of the proposed sensor, the determination of real samples was carried out with satisfactory results.

Electrochemical preparation of Ag nanoparticles/poly(methylene blue) functionalized graphene nanocomposite film modified electrode for sensitive determination of rutin

Ag nanoparticles/poly(methylene blue) functionalized graphene (AgNPs/PMB–GR) composite film modified Au electrode was firstly constructed via a facile electrochemical method. The scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were performed to characterize AgNPs/PMB–GR film modified electrode. The experimental results showed that GO not only could be electrochemically reduced to GR but also simultaneously successfully incorporated into the PMB film. The large wrinkled structure of PMB–GR gave more opportunities for the electrodeposition of AgNPs with the diameter of about 20–30nm integrate uniformly with the PMB–GR composite. The electrochemical behaviors of rutin at the modified electrode were investigated, and the results demonstrated that the AgNPs/PMB–GR could remarkably increase the redox currents of rutin. The effects of pH, scan rate and interference on the response of rutin were studied. The calibration curves for rutin were obtained over the ranges of 0.01–0.1, 0.1–2.0, and 2.0–10.0μM by DPV, respectively, and the lowest detectable concentration was 0.01μM. The AgNPs/PMB–GR/Au electrode exhibited good selectivity and high sensitivity for the determination of rutin content in tablet samples with satisfactory results.

Preparation and characterization of nanocomposites of poly-p-phenylene benzobisthiazole with graphene nanosheets

Poly-p-phenylene benzobisthiazole (PBT)/graphene nanocomposite films were fabricated using a simple method with methanesulfonic acid (MSA) as the processing solvent. In this approach, graphene nanosheets were exfoliated in the MSA solution of PBT using ultrasonication and mechanical stirring, and then processed into thin films. The structure and composition of as-prepared graphene oxide (GO) and reduced graphene oxides (rGO) were characterized by Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The electrical conductivity of pristine PBT was enhanced by 10 orders of magnitude upon incorporation of 5 wt% rGO nanosheets. The enhanced conductivity of the nanocomposites was interpreted by the percolation model. The thermo-oxidative stability of PBT was improved with the incorporation of both GO and rGOs, while rGOs showed more pronounced effect. On addition of only 5 wt% GO, the tensile strength and Young's modulus of PBT increased by ∼4-fold and ∼7-fold, respectively, whereas relatively inferior tensile properties were observed for the PBT/rGO nanocomposites. The enhanced mechanical properties could be attributed to the molecular-level dispersion of the exfoliated GO nanosheets in PBT matrix, as evidenced by the results from morphological studies. A modified Halpin–Tsai model has been used to evaluate the reinforcement or orientation effects of GO/rGO on the Young's modulus of the nanocomposites.

Electrochemiluminescence Biosensor Based on PEDOT‐PSS‐ Graphene Functionalized ITO Electrode

AbstractA novel and sensitive electrochemiluminescence (ECL) method for ethanol biosensor was developed by co‐immobilizing the enzyme and ECL reagent Ru(bpy)32+ on the poly‐(3,4‐ethylene dioxythiophene) and polystyrene sulfonate functionalized graphene (PEDOT‐PSS‐G) nanocomposite film. Positively charged Ru(bpy)32+ could be immobilized effectively on the electrode surface with the negatively charged PSS and graphene, which provided a stable ECL platform for further modification with the enzyme. Moreover, the introduction of PEDOT and graphene can be acted as a conducting pathway to accelerate the electron transfer due to the high conductivity. Such biosensor combined enzymatic selectivity with the amplification of PEDOT‐PSS‐G performed well with a wide linear range, high sensitivity and good stability. The sensing platform was successfully applied to determine the amounts of alcohol in real samples.