Graphene Oxide and Review and Functionalization and Sensor

Article Sections

• Introduction
• Graphene Oxide Applications Using Hydroxyl (OH) Functionalization
• Graphene Oxide Applications Using Epoxy Group Functionalization
• Applications of Graphene Oxide Using Carboxylic Group Functionalization
• Applications of Graphene Oxide Using π-π Stacking Functionalization
• Conclusion

Introduction

The growing interest in the development of new types of implantable and wearable electrochemical sensors for utilize in medical applications has helped to drive the development of graphene and other new materials. Graphene, discovered in 2004, is a carbon-based nanomaterial that takes the grade of an sp2 carbon canvas, with the atoms bundled in a honeycomb lattice,^1,two It has high intrinsic mobility, unrivaled malleability and impermeability, high theoretical specific surface area (2630 chiliad²/g for a single layer), and remarkable electron transport capabilities. Because of the properties imparted by its second structure, graphene becomes highly sensitive and selective when functionalized with a linker molecule, making it a promising candidate for a multitude of biosensing applications.^3-five

Graphene can take many forms, each with its ain characteristics: few-layer graphene (FLG),⁶ multi-layer graphene (MLG),⁷ graphene nanoplatelets (GNP),⁸ graphene oxide (Get),^10-12 and reduced graphene oxide (rGO).^nine FLG is used in sensors, batteries, and nanoelectronics devices, while both MLG and GNP are known for their applications equally conductive inks, plastics additives, and lubricants. rGO is similar to GO, simply information technology possesses a reduced oxygen-carbon ratio making it especially suitable for various chemic and biosensing applications.

Graphene oxide is usually produced by the Hummers method,^ten which is like shooting fish in a barrel and inexpensive. Go continues to generate high levels of interest among nanomaterials researchers because of its high conductivity after reduction, selectivity after functionalization, and sensitivity. This review focuses on GO, its functionalization methods, and its many applications.

Graphene oxide is comprised of a unmarried layer graphene sheet, covalently bonded to oxygen functional groups on the basal planes and edges of the sheet. On the basal planes, at that place are both hydroxyl and epoxy groups; the edges can include carboxyl, carbonyl, phenol, lactone, and quinone groups.^11-14 These oxygenated functional groups bind covalently with the carbon atoms in Go, creating oxidized regions of sp³- hybridized carbon atoms that disrupt the non-oxidized regions of the original sp² honeycomb network. Graphene sheets solitary take limited solubility in h2o due to the strong π-π bonds between layers, so Go or rGO are usually used for biosensing applications.¹⁵ The functional groups present on GO are polar, making it very hydrophilic and water-soluble, which is important for processing and chemical derivatization. On the other hand, these oxygen-based functional groups tin degrade the electronic, mechanical, and electrochemical backdrop of Get by creating meaning structural defects, reducing electrical electrical conductivity, and potentially limiting its directly application in electrically agile materials and devices. Nonetheless, Become can instead be functionalized by partially reducing it to rGO with various chemical or thermal treatments,¹⁵ in order to facilitate the transport of carriers.¹⁶ This chemical modification decreases its resistance past several orders of magnitude¹⁷ and transforms the cloth into a graphene-like, semiconducting material.

Chemic functionalization is an easy fashion to modify Get, and has proven extremely useful for creating sensors for biomedical, electrochemical, and diagnostic applications. The reactive and modifiable oxygenated functional groups of GO can be functionalized with different electroactive species.¹⁸ This covalent functionalization of specific molecules can mitigate the non-specific binding that typically occurs with plain graphene sensors. Many methods have been adult to minimize the disadvantages of GO while enhancing the advantages of graphene qualities.^ane For example, covalently bonding different chemical linkers to Become tin can modify the surface of the graphene and fine-tune its properties. Careful functionalization of GO increases its conductivity, stability, and selectivity for electrochemical sensing applications,^1,2,xviii as well as enhancing its sensitivity by increasing the surface area.

Applications of Functionalized Graphene Oxide

Graphene Oxide Applications Using Hydroxyl (OH) Functionalization

Hydroxyl groups attached to the basal planes of GO sheets can be effective attachment sites for different chemical agents. For example, the surface can be modified by silanization, a process that coats a surface with organofunctional alkoxysilane molecules. This modification technique has been shown to produce carbon nanomaterials with optimal chemical and physical properties for fabricating conducting films.^19-21

Designing nanomaterials that take potent metallic adsorption and antimicrobial capabilities for environmental,^23,24 catalytic,^25-27 and biomedical applications²⁸ has posed a challenge. In 2014, Carpio et al. conducted experiments on GO functionalization using ethylenediamine triacetic acid (EDTA), a strong chelating agent, to raise the multi-functionality of GO, thus increasing its metal adsorption and antimicrobial properties.²² In this report, GO was functionalized with N-(trimethoxysilylpropyl) ethylenediamine triacetic acid (EDTA-silane). In a dehydrationcondensation reaction, the hydrolysis of the trialkoxy groups in Si-EDTA creates -Si-OH groups that collaborate with the hydroxyl groups (OH-C) to class Si-O-C bonds. When compared to Go, GO-EDTA demonstrates improved antimicrobial characteristics with a x.ane% and seven.1% increase in cell inactivation of B. subtilis (Gram-positive) and C. metallidurans (Gram-negative), respectively. GO-EDTA also demonstrates maximum adsorption capacities for Cu²⁺ and Pbⁱⁱ⁺ that exceeds the capacities of traditional adsorbent materials. In addition, afterward 24-hour exposure to human corneal epithelial prison cell lines, GO-EDTA shows minimal toxicity on human cells, every bit 99% of the cell culture remained viable. This makes GO-EDTA a promising carbon nanomaterial for future clinical applications.

Another report used EDTA to functionalize rGO, by creating a rGO-EDTA composite suspended in Nafion-ethanol solution.²⁹ The rGO-EDTA/Nafion film was and then deposited onto a glassy carbon (GC) electrode, and this rGO-EDTA device could notice dopamine (DA) via oxidation.

Hu et al. investigated silanization, reduction, silanization combined with reduction, and in situ co-polymerization as methods for functionalizing Get, in order to amend tensile strength and solubility.³⁰ The hydroxyl groups on graphene oxide and rGO sheets were silanized with 3-methacryloxypropyltrimethoxysilane (MPS, True cat. No. 440159)³⁴ (Figure ane). H2o suspension tests for GO, rGO, MPS-Get, and MPS-rGO revealed that MPS-GO and MPS-rGO had enhanced water solubility. Hu et al. then functionalized Become and rGO derivatives with poly(methyl methacrylate) (Cat. Nos. 182230, 200336, 445746, and 182265, PMMA) via in situ co-polymerization in society to increase the mechanical properties of the polymer. The MPS-rGO/PMMA composites had thirty% more tensile strength when compared to pristine PMMA due to the stable dispersion of the nanosheets in the polymer matrix that increased the interfacial strength indicating potential for future industrial applications.³⁰

Figure 1. Silanization of Go using MPS, following co-polymerization of functionalized, silanized-GO with PMMA. Reproduced with permission from reference 30, copyright 2014 Elsevier.

Instead of silanization, hydroxyl groups on Get tin also exist functionalized by esterification. In one study, this functionalization occurred through a reaction with nitriles then separation of the products through filtration and/or centrifugation.³¹ Yuan et al. demonstrated that GO functionalized with poly(l-lactic) acid (Cat. Nos. 764590, 764698, 765112, 900295, etc., PLLA) improved its properties including tensile forcefulness, tensile fracture strength, and dispersibility.³²

In 2010, Become was functionalized via esterification to synthesize a GO framework for gas adsorption.³³ The researchers combined Become with benzene-1,4-diboronic acid (B14DBA, Cat. No. 417130) to course boronic esters (Figure two). In this case, unmarried layer GO sheets were crosslinked together, building a 3D porous network connected by benzenediboronic acid pillars. The framework structures had modifiable pore widths, volumes, and binding sites, making them extremely useful for gas storage.

Figure 2. GO sheets functionalized with B14DBA via covalent bonding of -OH groups to create GOF. Reproduced with permission from reference 33, copyright 2010 John Wiley and Sons.

Graphene Oxide Applications Using Epoxy Grouping Functionalization

Covalent functionalization of graphene oxide through modification of epoxy groups on the basal planes normally involves a nucleophilic assail at the α-carbon of the epoxide, and using an amine group to catalyze the band-opening reaction. For example, in 2008 Wang et al. used octadecylamine (ODA, True cat. No. 74750) every bit the nucleophile, thus opening the rings and creating polydispersed, chemically converted graphene oxide sheets (p-CCG).³⁴ This method produced GO as colloidal suspensions in organic solvents that could then exist spin-coated, printed onto diverse substrates, or fully reduced into high quality chemically modified graphene (CMG) films. These new properties make p-CCGs highly promising starting material for electrochemical sensors.

A similar study was conducted by Yang et al. using i-(3-aminopropyl)-3-methylimidazolium bromide (R-NH_two), an ionic liquid, to functionalize Become by the same band-opening machinery (Figure 3).³⁵ The p-CCGs produced had excellent solution-stability in polar solvents.³⁵ Likewise, these p-CCGs demonstrate potential for electrochemical applications, for example for chemically-modified electrodes.

Effigy 3. Become functionalized to prepare p-CCG. Reproduced with permission from reference 35, copyright 2009 Imperial Social club of Chemistry.

In 2015, Bandyopadhya et al. synthesized hexylaminefunctionalized rGO (rGO-HA)³⁶ by a nucleophilic add-on of the HA amine groups onto the Become epoxy groups. Hydrazine hydrate (Cat. Nos. 18412, 225819) was and then added to reduce the blended to the final rGO-HA product. This alkylamine functionalization resulted in the enhanced hydrophobicity of the rGO-HA sheets and immune them to exist well-dispersed in various organic solvents. The permeability of hydrogen gas into a synthesized rGO-HA picture show after coating on the surface of polyurethane (PU) decreased, suggesting a potential use in industrial hydrogen gas separation and purification.³⁶

Some other group used 3-aminopropyltriethoxysilane (APTS, True cat. No. 440140) to functionalize graphene oxide platelets via an SN_ii reaction between the epoxide and APTS amine groups.³⁷ The researchers were able to synthesize polydispersed, functionalized, and chemically converted graphene (f-CCG) that was soluble in many polar media. Due to its increased strength, the functionalized-Get production has applications as both bio-encapsulation and sensors, among other uses.

Shams et al. synthesized a nanocomposite of Get and ethylenediamine (EDA, True cat. No. E26266) under reflux at 50 °C for use as an electrochemical sensor to find fenitrothion in natural water.³⁸ In addition, EDA was used to crosslink Get and gold nanoparticles (AuNPs) in lodge to increase the hydrophilicity and dispersibility of GO in polar solvents with a decreased tendency to aggregate.¹

Figure 4. Scheme of fullerenol functionalizing GO via ester linkages. Reproduced with permission from the corresponding author.39

Applications of Graphene Oxide Using Carboxylic Group Functionalization

Like to hydroxyl and epoxy groups, carboxyl groups tin can be functionalized through activation and amidation or esterification with pocket-size molecules or polymer chemic linkers.^40-43 In 1 study, graphene oxide was activated with North,Due north'-Dicyclohexylcarbodiimide (DCC, Cat. No. D80002) and coupled with an esterification reaction using an allotropic carbon nanomaterial, fullerenol (C₆₀, Cat. No. 379646).⁵⁸ Like other allotropic carbon nanomaterials, C_sixty possesses superconductivity, photoconductivity, and nonlinear optical (NLO) properties. In some other report, Zhang et al. synthesized a graphene-C60 hybrid and investigated the NLO backdrop of this hybrid.³⁹ They found that the hydroxyl groups of fullerene formed covalent ester bonds with the carboxylic groups on GO (Figure 4). Liu et al. as well reported Go functionalization with another allotropic carbon material, porphyrin (TPP-NH₂). In this instance, the carboxylic groups of Become bonded to the amine group on TPP-NH₂ via activation coupled with amidation instead of esterification.⁴⁴ The GO-hybrids exhibited cracking potential for awarding as optical limiting and optical switching materials for optoelectronic and photonic devices.

Su et al. described a method of fabricating diaminefunctionalized GO films through covalent bonding with the -COOH groups on the GO sheets.⁴⁵ Using a well-established procedure, N-(3-dimethylaminopropyl)-Due north'-ethylcarbodiimide hydrochloride (EDC, Cat. No. 03449) and N-hydroxysuccinimide (NHS, True cat. No. 130672) served equally coupling reagents.⁴⁵ Novel impedance-type humidity sensors were fabricated by blanket diamine-functionalized Go films onto alumina or plastic substrates. These sensors, comprised from the diamine-functionalized Become film, worked across a wide humidity range, and exhibited a high sensitivity, high flexibility, high long-term stability, satisfactory linearity, a small hysteresis, a short response/recovery time, and merely a weak dependence on temperature.

Other studies of esterification include grafting epoxy chains onto graphene oxide sheets via ester linkages with the carboxyl groups on GO, which can raise the mechanical and thermal properties of graphene oxide while also increasing interfacial interactions.⁶³ This blazon of functionalized Go also tin exist used to create polymer solar cells (PSCs).

Cesium-neutralized GO (Get-Cs) has been used to transform GO into an electron extraction layer (EEL) in polymer solar cells (PSC).⁴⁶ Cesium carbonate (Cs_iiCO₃ , Cat. Nos. 202126, 441902, 554855, 255645) was introduced to GO, resulting in neutralization of the -COOH groups to -COOCs groups. This product demonstrated promise as an excellent electron-extraction layer in solar cell devices.

Graphene oxide has besides been functionalized with biomolecules. For example, in 2010, Shen et al. functionalized Go with bovine serum albumin (BSA) via diimide-activated amidation, a pop method for connecting proteins to other materials.⁴⁷ This procedure resulted in a GO-BSA conjugate, with no prove of protein denaturation. Cyclic voltammogram (CV) measurements indicated that the cohabit maintained bioactivity and exhibited excellent h2o solubility, making it suitable for interaction with biological substrates.

The awarding of Get as a biosensor for clinical diagnosis was investigated by functionalizing carboxylic groups of GO with glucose oxidase (GOx), thus producing a biocompatible GO-GOx biosensor.⁵³ In this study, a cell line derived from human retinal paint epithelium (RPE), a neuroectodermal derivative that is vital for photoreceptor survival, was introduced onto Become-GOx. The complex demonstrated excellent biocompatibility. The GO-based glucose biosensors exhibited a wide linear range, good stability, high sensitivity, excellent reproducibility, and bang-up biocompatibility to human RPE cells, suggesting that these biosensors have tremendous potential for utilize in in vivo clinical diagnostics, such as diabetic retinopathy. The functionalization of Go's carboxyl groups as well demonstrated GO's promise in creating enzyme electrodes that can exist used in biomedicine and clinical diagnostics.

Figure five. Schematic diagram depicting the surface functionalization of the formation of the HRP/ERGO-NP/ITO modified electrode applied for detection of H2O2 . Reproduced with permission from reference 48, copyright 2014 Electrochemical Order.

Yagati et al. reported an electrochemical sensor based on electrochemical co-reduction of graphene oxide/nanoparticle (ERGO-NP) composite films by the chronoamperometry method on indium tin oxide (ITO) electrodes, which was then utilized to sense H₂O_ii by direct electron transfer past horseradish peroxidase (HRP).⁴⁸ Covalent bonding between the amine groups of the enzyme and the carboxylate concluding of rGO and nanoparticles activated with 3-mercaptopropionic acid (Cat. No. M5801) was achieved through EDC/NHS coupling, leading to the germination of strong amide bonds (Figure 5).

In another study, graphene oxide was functionalized past the coupled reactions of EDC activation and polyethylene glycol (PEG) amidation.⁴⁹ The PEG-GO nanosheet products had excellent aqueous solubility and stability in biological solutions, including serum. Liu et al. then used the functionalized Get derivative to create a circuitous with diverse insoluble, aromatic camptothecin analogues, showing the potential of functionalized GO to deliver water-insoluble cancer drugs.

In 2008, Mohante and Berry investigated ii approaches for covalent functionalization of Get via activation coupled with amidation. The resulting chemically modified graphene (CMG) demonstrated potential application in improving the nano/ bio interface for biodetection, bioactuation, and diagnostics.⁵⁰ Electrical label of the GO-derivatives showed that the graphene-DNA (1000-DNA) hybrid had a 128% increase in conductivity due to DNA's negative charge on the p-blazon Become, while the hybridization of Thousand-DNA with cDNA generated approximately a single quantum of conducting hole, increasing conductivity by 71%.⁵¹

In another study, Liu et al. investigated the possibilities of functionalized Go as a selective and sensitive hybridized DNA biosensor.⁴³ Get was activated with EDC/sulfo-NHS, using similar chemistry to EDC/NHS described to a higher place, which converts the carboxylic groups of Go into their amine-reactive NHS-ester forms. The functionalized carboxylic groups leap to aminomodified ssDNA, which allowed a complementary ssDNA labeled with aureate nanoparticles (AuNPs) to attach to the Become-DNA probe in a hybridization reaction.

Applications of Graphene Oxide Using π-π Stacking Functionalization

The excellent adsorption of organic aromatic molecules on GO nanosheets tin be attributed to both π-π stacking and hydrophobic interactions betwixt Get and other aromatic molecules. In the past, studies have shown that the incorporation of sulfonic acid onto the surface of Get sheets can significantly increment its proton electrical conductivity.^52-54 Su et al. used 3,4,9,10-perylenetetracarboxylic diimide bis-benzene sulfonic acid (PDI), a big planar aromatic electron acceptor, and pyrene-i- sulfonic acid (PyS), a larger, planar effluvious electronic donor, to non-covalently functionalize rGO.⁵⁵ PyS and PDI molecules with negative charges were able to strongly braze onto the hydrophobic surface of graphene sheets via π-π interactions, without disrupting its electronic conjugation. This produced rGO-based composites with modifiable electronic backdrop that could be utilized to produce electronic devices.

In society to fix water soluble CMG sheets for excellent stable-dispersion in polar solvents with enhanced conductivity, GO was reduced and at the same time non-covalently functionalized with 1-pyrenebutyrate (PB- ), also using π-π interactions.¹⁹ Here, Atomic number 82- acted equally a stabilizer during the transformation of GO to rGO, as the effluvious pyrene undergoes π-π stacking with the basal plane of rGO. The resulted rGO-PBwas able to form homogenous dispersion in water, and films cast from this dispersion were 7 times more than conductive than that from not-functionalized GO dispersions.

In society to take advantage of the selectivity and sensitivity of Get-based biosensors, Lu et al. non-covalently functionalized GO with aromatic compounds and nucleobases, resulting in a GO platform that could notice both Deoxyribonucleic acid and proteins.⁵⁶ Immobilizing the dye-labeled ssDNA with groovy analogousness to GO via π-π interactions,^49,57 caused quenching of the dye fluorescence.⁸⁰ Subsequent bounden of the dye-labeled ssDNA and the target molecule resulted in a conformational change of the dyelabeled Deoxyribonucleic acid, interfering with its interactions with and releasing it from GO, which led to the reappearance of the fluorescence betoken. This proof of concept report confirmed the possibility of developing a fluorescence-enhanced Go-based device with sensitive and selective detection for a target molecule.

A similar written report used the aforementioned quenching effect of Go with hairpin-structured DNA to produce a GO-based molecular buoy (MB) — a single-stranded oligonucleotide hybridization probe to recognize a target analyte with a costless probe sequence. This approach demonstrated stronger affinity of DNA for GO and sensitive and selective detection of specific DNA sequences.⁵⁸ Dong et al. fabricated a Become-based platform to notice biomolecules using fluorescence resonance free energy transfer (FRET) from quantum dots (QDs) (with a MB) to Get.⁵⁹ The QDs, modified with a MB (MB-QDs), were able to act as probes on Become, thus allowing the recognition of specific Deoxyribonucleic acid sequences. The strong π-π stacking interactions between MB-QDs and Become resulted in quenching of the QDs fluorescence. In the presence of the Dna target, the distance betwixt QDs and Get increased, weakening the GO MB-target interactions and thus significantly decreasing the FRET and increasing the QDs fluorescence intensity, indicating a facile method for target recognition.

Wang et al. described a method for functionalization of GO with polyaniline (PANI) via electrostatic interactions, hydrogen bonding, and π-π stacking interactions.^lx,61 The Become-PANI composites were further optimized via in situ polymerization of monomer in the presence of GO, using a mild oxidant, thus improving the electrochemical performance of the blended as a supercapacitor electrode. The composites had increased initial specific capacitances, improved capacitance memory, and decreased internal resistance, when compared to a PANI electrode alone.

Graphene oxide has too been functionalized with TPE-So_iiiNa via π-π stacking to improve the selectivity of biosensors based on aggregation-induced emission (AIE) for detection of bovine serum albumin (BSA).⁶² In AIE biosensors, non-luminescent molecules are induced to emit efficiently by amass germination.^63-65 TPE-SO₃Na is an AIE molecule that tin detect bio-macromolecules such as BSA.⁶⁶ The binding of BSA prevents the free rotation of the AIE molecule, making TPE-SO_iiiNa highly emissive in its presence.⁶⁷ While TPE-So₃Na is highly sensitive for BSA, information technology displays no selectivity for BSA, as it responds similarly to many other bio-macromolecules.^66,67 Withal, with the addition of GO, the detection of BSA with good sensitivity and selectivity can be achieved.⁷¹ This is because the π-π interactions betwixt the AIE molecule and Get quench fluorescence, but only when the binding effect of AIE molecules and the protein is stronger than the π-π interaction. Since the binding effect of TPE–SO₃Na for BSA is slightly higher than other proteins, selectivity was achieved.

Due to the resulting strength of the π-π interactions, functionalization of graphene surfaces with pyrene (PY) derivatives has too been studied. In 2018, Wang et al. investigated functionalization of thermally reduced GO (trGO) with pyrene derivatives, terminated by the hydrogen bonding unit ureidopyrimidinone (UP) to grade (trGO)-UPPY.⁶⁸ The graphene surface was modified with pyrene groups which formed π-π bonds with UPPY (Figure six). This Layer-by-Layer (LBL) selfassembly technique was repeated to grade films of trGO-UPPY that compose both hydrogen bonds and π-π bonds. The resulted multilayer films demonstrated potential as excellent electron conductors to improve electron transfer.

Figure half-dozen. A) Formation of UPPY-UPPY homodimer B) Grafting of UPPY onto trGO through π–π bonding and germination of multilayer trGO-UPPY through LBL assembly technique. Reproduced with permission from the corresponding author.68

In another biomedical study, Wahid et al. examined Go equally a potential drug carrier through non-covalent functionalization.⁷⁴ Effluvious organic molecules (drugs) that were not-covalently attached to graphene surfaces were more easily released than those bonded covalently. Wahid et al. also reported the successful functionalization of graphene sheets with Ramizol, an antibiotic with antioxidant backdrop.⁶⁹ Due to its planar geometry, Ramizol tin form π-π bonds with graphene surfaces; this interaction has been previously shown to facilitate the exfoliation of graphite into graphene sheets, while stabilizing the sheets in aqueous environments.

Some other method for noncovalent functionalization of Go was demonstrated by Liu et al. using a redox reaction.⁷⁰ This spontaneous redox reaction occurs in an aqueous mixture containing Become, FeCl₃ , and K₃ [Iron(CN)₆ ], resulting in the formation of Prussian blue (PB) nanocubes on the surface of Become. This Get-Pb nanocomposite was cast onto a GC electrode surface, demonstrating great stability, practiced reproducibility, excellent electrochemical action, and high sensitivity for electrocatalytic reduction of H_twoO_two . In add-on, Become increased the effective surface area of the GC electrode, thus enhancing sensitivity. This Go-PB nanocomposite showed great hope as a potential biofuel cell electrode, too as a novel electrochemical sensor.

Conclusion

Graphene oxide sheets are carbon-based nanomaterials with hydroxyl, epoxy, carboxyl, and other functional groups fastened to their basal planes and edges. Various functionalization methods accept been used to heighten their mechanical, electrical, and chemical properties. For functionalization of hydroxyl groups, silanization on GO and rGO with molecules such as MPS tin improve both tensile strength and solubility. In add-on, esterification with benzene-1,4-diboronic acid can link multiple single layer GO sheets into a 3D porous network. For covalent functionalization of epoxy groups on Go, many methods involve attack on the α-carbon of the epoxide, thus creating nanosheets with high dispersibility in polar solvents and films with enhanced gas barrier properties. For the functionalization of carboxylic groups, some common methods include activation coupled with esterification, which solubilizes GO; other methods include activation coupled with amidation, which facilitates attachment of mutual biomolecules to GO. The power to enhance its properties demonstrates the broad range of GO'southward potential applications, especially in the field of biomedicine, water-insoluble drug delivery, clinical diagnostics, and specific DNA sequence detection. For not-covalent functionalization, π-π stacking and electrostatic interactions enhance the electrical backdrop of Become, improving the electron transfer procedure, increasing the specific capacitance, and decreasing the internal resistance. Not-covalent functionalization of Become has improved as an constructive and tunable arroyo for fabricating electrochemical sensors and selective biomolecule detectors. In summary, modified graphene oxide sheets are at present being widely applied in the evolution of devices for use in fields of industrial, environmental, and biomedical research, and their full potential is just beginning to be adult.

References

one.

Shams N, Lim HN, Hajian R, Yusof NA, Abdullah J, Sulaiman Y, Ibrahim I, Huang NM. Electrochemical sensor based on gold nanoparticles/ethylenediamine-reduced graphene oxide for trace determination of fenitrothion in water. RSC Adv.. vi (92): 89430-89439. http://dx.doi.org/10.1039/c6ra13384c

7.

Krajewska A, Pasternak I, Sobon G, Sotor J, Przewloka A, Ciuk T, Sobieski J, Grzonka J, Abramski KM, Strupinski Due west. 2017. Fabrication and applications of multi-layer graphene stack on transparent polymer. Appl. Phys. Lett.. 110 (4): 041901. http://dx.doi.org/10.1063/ane.4974457

10.

Alam SN, Sharma N, Kumar L. 2017. Synthesis of Graphene Oxide (Get) past Modified Hummers Method and Its Thermal Reduction to Obtain Reduced Graphene Oxide (rGO)*. Graphene. 06 (01): 1-18. http://dx.doi.org/x.4236/graphene.2017.61001

11.

Compton OC, Nguyen ST. 2010. Graphene Oxide, Highly Reduced Graphene Oxide, and Graphene: Versatile Edifice Blocks for Carbon-Based Materials. Small. 6 (6): 711-723. http://dx.doi.org/ten.1002/smll.200901934

16.

Eda G, Mattevi C, Yamaguchi H, Kim H, Chhowalla Grand. 2009. Insulator to Semimetal Transition in Graphene Oxide. J. Phys. Chem. C. 113 (35): 15768-15771. http://dx.doi.org/10.1021/jp9051402

17.

Gómez-Navarro C, Weitz RT, Bittner AM, Scolari Chiliad, Mews A, Burghard Grand, Kern Thou. 2007. Electronic Transport Properties of Individual Chemically Reduced Graphene Oxide Sheets. Nano Lett.. seven (eleven): 3499-3503. http://dx.doi.org/ten.1021/nl072090c

18.

Chen D, Feng H, Li J. 2012. Graphene Oxide: Preparation, Functionalization, and Electrochemical Applications. Chem. Rev.. 112 (11): 6027-6053. http://dx.doi.org/10.1021/cr300115g

xix.

Xu Y, Bai H, Lu G, Li C, Shi Yard. 2008. Flexible Graphene Films via the Filtration of H2o-Soluble Noncovalent Functionalized Graphene Sheets. J. Am. Chem. Soc.. 130 (xviii): 5856-5857. http://dx.doi.org/10.1021/ja800745y

20.

Bekyarova E, Itkis ME, Ramesh P, Berger C, Sprinkle M, de Heer WA, Haddon RC. 2009. Chemical Modification of Epitaxial Graphene: Spontaneous Grafting of Aryl Groups. J. Am. Chem. Soc.. 131 (4): 1336-1337. http://dx.doi.org/10.1021/ja8057327

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