Quasi-Molecular Fluorescence from Graphene Oxide

Galande, Charudatta; Mohite, Aditya; Naumov, Anton V.; Gao, Wei; Ci, Lijie; Ajayan, Anakha; Gao, Hui; Srivastava, Anchal; Weisman, R. Bruce; Ajayan, Pulickel M.

doi:10.1038/srep00085

Cited by 277 publications

(340 citation statements)

References 29 publications

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“…C-O bonds may be attributed to the epoxy functional groups present on the basal plane of GO. O-Sn-O vibration is observed at about 700 cm 1 in the spectra which is also attributed to SnO 2 [26].…”

Section: Fabrication Of the Sensorsmentioning

confidence: 87%

Graphene oxide/SnO2 Nanocomposite as Sensing Material for Breathalyzers: Selective Detection of Ethanol in the presence of Automotive CO and Hydrocarbons Emissions

et al. 2017

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Abstract. SnO 2 was ultrasonically deposited (precipitated) in the presence of di erent amounts of graphene oxide (GO) prepared by the modi ed Hummers' method. The resulting nanocomposites were used as sensing material for the detection of 1000 ppm CO and VOCs including ethanol, acetone and toluene, and CH 4 in a temperature range of 150-300 C. The nanocomposites were characterized by Raman spectroscopy, XRD, BET surface area measurement, FT-IR, and SEM methods. It seems that SnO 2 layers were deposited on the GO surface and incorporated into the matrix. This resulted in 47% increase in the nanocomposite BET surface area. The addition of 0.1 wt% GO to SnO2 increased the response to CO by about 6 times at 300 C. 0.05 wt% GO as an optimum amount was included in SnO2 up to 2-fold enhancement in response to ethanol, and toluene was observed. At 250 C, the highest response to ethanol was obtained, which is 120, 114, 1400, and 15 times larger than the responses to CO, toluene, methane and acetone, respectively, making the sensors quite selective to ethanol. Furthermore, this sensor exhibited good response in the low concentration of ethanol.

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Section: Fabrication Of the Sensorsmentioning

confidence: 87%

Graphene oxide/SnO2 Nanocomposite as Sensing Material for Breathalyzers: Selective Detection of Ethanol in the presence of Automotive CO and Hydrocarbons Emissions

et al. 2017

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“…In particular, innovative carbon-based nanomaterials such as graphene quantum dots (GQDs) and graphene oxide quantum dots (GOQDs) have attracted much interest as stable, nontoxic, photoluminescent nanomaterials with possible applications in chemical and biological sensors, drug delivery, bio-imaging and energy conversion [7][8][9][10][11][12][13]. The physical origin of the photoluminescence (PL) from these carbonbased nanoparticles is still quite controversial and different mechanisms have been suggested, possibly acting together, mainly based on quantum confinement in sp 2 domains with a strong influence from edge and oxygen-containing functional groups [14][15][16][17][18]. Nonetheless, several groups have reported a characteristic fluorescence with uniform and stable features in aqueous solution of GOQDs prepared by a variety of methods, either based on bottom-up or on top-down synthesis from graphite [19][20][21][22][23][24][25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Sensitivity to Heavy-Metal Ions of Unfolded Fullerene Quantum Dots

Ciotta¹,

Paoloni²,

Prosposito³

et al. 2017

Preprint

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A novel type of graphene-like quantum dots, synthesized by oxidation and cage-opening of C60 buckminsterfullerene, has been studied as a fluorescent and absorptive probe for heavy-metal ions.The lattice structure of such unfolded fullerene quantum dots (UFQDs) is distinct from that of graphene since it includes both carbon hexagons and pentagons. The basic optical properties, however, are similar to those of regular graphene oxide quantum dots. On the other hand, UFQDs behave quite differently in the presence of heavy-metal ions, in that multiple sensitivity to Cu 2+ , Pb 2+ and As(III) was observed through comparable quenching of the fluorescent emission and different variations of the transmittance spectrum. By dynamic light scattering measurements we confirmed, for the first time in metal sensing, that this response is due to multiple complexation and subsequent aggregation of UFQDs. Nonetheless, the explanation of the distinct behaviour of transmittance in the presence of As(III) and the formation of precipitate with Pb 2+ require further studies. These differences, however, also make it possible to discriminate between the three metal ions in view of the implementation of a selective multiple sensor.

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“…In each case a broad emission peak centered at excitation/emission coordinates 350/540 nm is manifest with progressive decrement of the emission intensity with the increase of the oxidation degree of the graphene planes. The fluorescence of GO is a complex and already faced up issue [20][21][22]. It is not here the place for an in-depth review and analysis of the quantum mechanical processes at the basis of the GO emission.…”

Section: Go Suspension Characterization (Different Oxidation Time)mentioning

confidence: 99%

Photochemical stability and reactivity of graphene oxide

et al. 2015

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The photoreactivity of graphene oxide (GO) suspensions was investigated with a double aim: i) to give insights into the previously reported photo-reduction process, which allows a partial elimination of the oxygen-containing groups from the 2D graphitic structure; ii) to explore the possible use of GO as photo-activator able to promote the photo-transformation/abatement of organic molecules. To reach these goals and clarify some peculiar aspects of the photochemistry of GO till now obscure or confuse, we synthesized and characterized stable GO suspensions which were then subjected to UV-Vis irradiation for prolonged times. GO underwent partial photoreduction with the release of gaseous molecules and soluble organic species (e.g. carboxylic acid).The mechanisms of photo-reduction occurring under air or N 2 are different, as assessed by the release in solution of diverse soluble molecules. In the presence of oxygen, at long irradiation time, a complete solubilization of the graphenic structures was observed. No difference in the nature and amount of released gases (principally CO 2 and CO) was observed in the oxic or anoxic conditions.The possible use of GO as photo-activator was evaluated by using phenol as probe molecule. GO revealed a double role of photo-activator and reagent in phenol degradation, as competition was assessed between GO self-transformation/reduction and phenol degradation. At prolonged irradiation time a marked reactivity of the photoformed species was observed and the complete degradation was achieved for both organic small molecules formed from GO and the phenol added as probe molecule.

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Quasi-Molecular Fluorescence from Graphene Oxide

Cited by 277 publications

References 29 publications

Graphene oxide/SnO2 Nanocomposite as Sensing Material for Breathalyzers: Selective Detection of Ethanol in the presence of Automotive CO and Hydrocarbons Emissions

Graphene oxide/SnO2 Nanocomposite as Sensing Material for Breathalyzers: Selective Detection of Ethanol in the presence of Automotive CO and Hydrocarbons Emissions

Sensitivity to Heavy-Metal Ions of Unfolded Fullerene Quantum Dots

Photochemical stability and reactivity of graphene oxide

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