scholarly journals Ultrathin Functional Polymer Modified Graphene for Enhanced Enzymatic Electrochemical Sensing

Biosensors ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 16 ◽  
Author(s):  
Anitha Devadoss ◽  
Rhiannan Forsyth ◽  
Ryan Bigham ◽  
Hina Abbasi ◽  
Muhammad Ali ◽  
...  
Keyword(s):  
Single Layer ◽  
Chemical Vapor ◽  
Electrochemical Analysis ◽  
Electrochemical Sensing ◽  
Single Layer Graphene ◽  
Monolayer Graphene ◽  
Polymer Layers ◽  
Thin Polymer ◽  
Amine Groups ◽  
Modified Graphene

Grafting thin polymer layers on graphene enables coupling target biomolecules to graphene surfaces, especially through amide and aldehyde linkages with carboxylic acid and primary amine derivatives, respectively. However, functionalizing monolayer graphene with thin polymer layers without affecting their exceptional electrical properties remains challenging. Herein, we demonstrate the controlled modification of chemical vapor deposition (CVD) grown single layer graphene with ultrathin polymer 1,5-diaminonaphthalene (DAN) layers using the electropolymerization technique. It is observed that the controlled electropolymerization of DAN monomer offers continuous polymer layers with thickness ranging between 5–25 nm. The surface characteristics of pure and polymer modified graphene was examined. As anticipated, the number of surface amine groups increases with increases in the layer thickness. The effects of polymer thickness on the electron transfer rates were studied in detail and a simple route for the estimation of surface coverage of amine groups was demonstrated using the electrochemical analysis. The implications of grafting ultrathin polymer layers on graphene towards horseradish peroxidase (HRP) enzyme immobilization and enzymatic electrochemical sensing of H2O2 were discussed elaborately.

scholarly journals Effect of a Balanced Concentration of Hydrogen on Graphene CVD Growth

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
S. Chaitoglou ◽  
E. Pascual ◽  
E. Bertran ◽  
J. L. Andujar
Keyword(s):  
Copper Substrate ◽  
Single Layer ◽  
Chemical Vapor ◽  
Experimental System ◽  
Single Layer Graphene ◽  
Growth Time ◽  
Monolayer Graphene ◽  
Flow Ratio ◽  
Large Area ◽  
Hydrogen Flow

The extraordinary properties of graphene make it one of the most interesting materials for future applications. Chemical vapor deposition (CVD) is the synthetic method that permits obtaining large areas of monolayer graphene. To achieve this, it is important to find the appropriate conditions for each experimental system. In our CVD reactor working at low pressure, important factors appear to be the pretreatment of the copper substrate, considering both its cleaning and its annealing before the growing process. The carbon precursor/hydrogen flow ratio and its modification during the growth are significant in order to obtain large area graphene crystals with few defects. In this work, we have focused on the study of the methane and the hydrogen flows to control the production of single layer graphene (SLG) and its growth time. In particular, we observe that hydrogen concentration increases during a usual growing process (keeping stable the methane/hydrogen flow ratio) resulting in etched domains. In order to balance this increase, a modification of the hydrogen flow results in the growth of smooth hexagonal SLG domains. This is a result of the etching effect that hydrogen performs on the growing graphene. It is essential, therefore, to study the moderated presence of hydrogen.

Epitaxial Chemical Vapor Deposition Growth of Single-Layer Graphene over Cobalt Film Crystallized on Sapphire

ACS Nano ◽  
2010 ◽  
Vol 4 (12) ◽  
pp. 7407-7414 ◽  
Author(s):  
Hiroki Ago ◽  
Yoshito Ito ◽  
Noriaki Mizuta ◽  
Kazuma Yoshida ◽  
Baoshan Hu ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Single Layer ◽  
Chemical Vapor ◽  
Single Layer Graphene ◽  
Chemical Vapor Deposition Growth ◽  
Cobalt Film ◽  
Layer Graphene

scholarly journals Electrochemical Characterization of CVD-Grown Graphene for Designing Electrode/Biomolecule Interfaces

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 241
Author(s):  
Keishu Miki ◽  
Takeshi Watanabe ◽  
Shinji Koh
Keyword(s):  
Electrochemical Properties ◽  
Electrode Materials ◽  
Electrochemical Impedance ◽  
Chemical Vapor ◽  
Charge Transfer Resistance ◽  
Monolayer Graphene ◽  
Transfer Resistance ◽  
Graphene Electrode ◽  
Before And After ◽  
Modified Graphene

In research on enzyme-based biofuel cells, covalent or noncovalent molecular modifications of carbon-based electrode materials are generally used as a method for immobilizing enzymes and/or mediators. However, the influence of these molecular modifications on the electrochemical properties of electrode materials has not been clarified. In this study, we present the electrochemical properties of chemical vapor deposition (CVD)-grown monolayer graphene electrodes before and after molecular modification. The electrochemical properties of graphene electrodes were evaluated by cyclic voltammetry and electrochemical impedance measurements. A covalently modified graphene electrode showed an approximately 25-fold higher charge transfer resistance than before modification. In comparison, the electrochemical properties of a noncovalently modified graphene electrode were not degraded by the modification.

Performance of single layer graphene obtain by chemical vapor deposition on gold electrodes

2019 ◽  
Vol 98 ◽  
pp. 107510 ◽  
Author(s):  
Bianca Tincu ◽  
Ioana Demetrescu ◽  
Andrei Avram ◽  
Vasilica Tucureanu ◽  
Alina Matei ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Single Layer ◽  
Chemical Vapor ◽  
Single Layer Graphene ◽  
Gold Electrodes ◽  
Layer Graphene

Chemical Vapor Deposited Graphene for Opto-Electronic Applications

2016 ◽  
Vol 39 ◽  
pp. 57-68
Author(s):  
Vikram Passi ◽  
Amit Gahoi ◽  
Sarah Riazimehr ◽  
Stefan Wagner ◽  
Andreas Bablich ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Spectral Response ◽  
Single Layer ◽  
Chemical Vapor ◽  
Adsorbed Water ◽  
Single Layer Graphene ◽  
Ambient Conditions ◽  
Transfer Length ◽  
Type Silicon ◽  
P Type

In this work, fabrication and characterisation of graphene photodiodes and transfer length method structures is presented. Graphene growth is carried out using a thermal chemical vapor deposition process on copper foils and subsequently transferred onto silicon-dioxide/silicon substrate. Comparison of electrical and optical characteristics of the photodiodes, which are fabricated on both n-type and p-type silicon, is shown. The photodiodes fabricated on n-type silicon show good rectifying behaviour when compared with photodiodes fabricated on p-type silicon. Spectral response of graphene photodiodes is measured to be less than 0.2 mAW-1 which is attributed to the light absorbance of 2.3% for single layer graphene. Transfer length method device structures are also fabricated and contact resistance is calculated and plotted as a function of spacing between the contacts. The calculated contact resistance (RcW) is 0.87 kΩ.µm. The latter structures are also characterised under various ambient conditions, before and after annealing. The value of contact resistance reduces from 0.87 kΩ.µm to 0.75 kΩ.µm after annealing. This reduction is attributed to the improvement in bonding between graphene and metal. Measurements under vacuum show an increase in contact resistance which is attributed to the removal of adsorbed water molecules on the surface on graphene. The sheet resistivity of graphene is calculated to be between 1.17 kΩ/□ and 3.67 kΩ/□.

Oxidation of CVD Growth Single-Layer Graphene

2013 ◽  
Vol 790 ◽  
pp. 7-10 ◽  
Author(s):  
Hui Gao ◽  
Yin Zhang
Keyword(s):  
Vapor Deposition ◽  
Acid Treatment ◽  
Oxidation Process ◽  
Single Layer ◽  
Chemical Vapor ◽  
Strong Acid ◽  
Single Layer Graphene ◽  
Layer Graphene ◽  
Potential Applications ◽  
Cvd Growth

Recently, oxidized chemical vapor deposition (CVD) growth graphene has drawn much attention due to its potential applications in the field of optoelectronics. In this article, we report a simple, scalable and efficient method to synthesize oxidized CVD growth single-layer graphene by the strong acid treatment. The results indicate that oxidation process successfully introduced more defects and oxygen-containing groups into the lattice of graphene.

Laser direct writing of graphene patterns

2011 ◽  
Vol 1365 ◽  
Author(s):  
J.B. Park ◽  
W. Xiong ◽  
Z.Q. Xie ◽  
M. Mitchell ◽  
Y. Gao ◽  
...  
Keyword(s):  
Single Layer ◽  
Chemical Vapor ◽  
High Growth ◽  
High Growth Rate ◽  
Single Layer Graphene ◽  
Direct Writing ◽  
Optically Pumped ◽  
Scan Speed ◽  
Thin Nickel ◽  
532 Nm

ABSTRACTRapid growth of single-layer graphene using laser-induced chemical vapor deposition (LCVD) with a visible CW laser (λ = 532 nm) irradiation at room temperature was investigated. In this study, an optically-pumped solid-state laser with a wavelength of 532 nm irradiates a thin nickel foil to induce a local temperature rise, thereby allowing the direct writing of graphene patterns about ~10 μm in width with high growth rate on precisely controlled positions. It is demonstrated that the fabrication of graphene patterns can be achieved with a single scan for each graphene pattern using LCVD with no annealing or preprocessing of the substrate. The scan speed reaches to about ~50 um/s, which indicates that the graphene pattern with 1:1 aspect ratio (x:y) can be grown in 0.2 sec. The patterned graphene on nickel was transferred to SiO2/Si substrate for fabrication of electrical circuits and sensor devices.

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