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Controllable Edge Oxidation and Bubbling Exfoliation Enable the Fabrication of High Quality Water Dispersible Graphene

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ABSTRACT

Despite significant progresses made on mass production of chemically exfoliated graphene, the quality, cost and environmental friendliness remain major challenges for its market penetration. Here, we present a fast and green exfoliation strategy for large scale production of high quality water dispersible few layer graphene through a controllable edge oxidation and localized gas bubbling process. Mild edge oxidation guarantees that the pristine sp2 lattice is largely intact and the edges are functionalized with hydrophilic groups, giving rise to high conductivity and good water dispersibility at the same time. The aqueous concentration can be as high as 5.0 mg mL−1, which is an order of magnitude higher than previously reports. The water soluble graphene can be directly spray-coated on various substrates, and the back-gated field effect transistor give hole and electron mobility of ~496 and ~676 cm2 V−1 s−1, respectively. These results achieved are expected to expedite various applications of graphene.

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Applications of water soluble graphene thus formed.(a) IDS-VG curve of water soluble graphene transistors at VD = 150 mV, the insert shows the schematic diagram and SEM image of the FET device. (b) The electron and hole mobility statistics of graphene based FET in previous reports (black circles: based on reduced graphene oxide, red circles: based on CVD graphene) and this work (red star). Scale bar, 10 μm (a).
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f3: Applications of water soluble graphene thus formed.(a) IDS-VG curve of water soluble graphene transistors at VD = 150 mV, the insert shows the schematic diagram and SEM image of the FET device. (b) The electron and hole mobility statistics of graphene based FET in previous reports (black circles: based on reduced graphene oxide, red circles: based on CVD graphene) and this work (red star). Scale bar, 10 μm (a).

Mentions: To determine the transport properties of the synthesized graphene films, back-gated graphene field effect transistors FETs were fabricated on 300 nm SiO2/Si substrates. The inset of Fig. 3a shows the schematic diagram and SEM image of the fabricated FETs. Highly reproducible transfer characteristics (IDS-VG) of the FETs measured at room temperature under ambient conditions. The typical IDS-VG curve measured at a VDS of 150 mV shows that the gate can cause either hole or electron conduction. The Dirac point of the FETs shifts slightly to a positive gate at VG ~ 25 V, demonstrating light p-type hole doping performance. According to the two slopes of the linear regions on both sides of the V-shaped curve, the hole mobility is μh ~ 496 cm2 V−1 s−1 and the electron mobility is μe ~ 676 cm2 V−1 s−1. As shown in Fig. 3b, the electron mobility of our water-dispersible graphene is much higher than that of graphene obtained by oxidation-reduction approaches25262728, and is also comparable to that of graphene films fabricated through high temperature CVD approaches2930313233343536373839. Considering that the spray coating progress is violent and inevitably introduces defects, impurities, wrinkles or overlaps, the performance of the FETs may be underestimated.


Controllable Edge Oxidation and Bubbling Exfoliation Enable the Fabrication of High Quality Water Dispersible Graphene
Applications of water soluble graphene thus formed.(a) IDS-VG curve of water soluble graphene transistors at VD = 150 mV, the insert shows the schematic diagram and SEM image of the FET device. (b) The electron and hole mobility statistics of graphene based FET in previous reports (black circles: based on reduced graphene oxide, red circles: based on CVD graphene) and this work (red star). Scale bar, 10 μm (a).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5036305&req=5

f3: Applications of water soluble graphene thus formed.(a) IDS-VG curve of water soluble graphene transistors at VD = 150 mV, the insert shows the schematic diagram and SEM image of the FET device. (b) The electron and hole mobility statistics of graphene based FET in previous reports (black circles: based on reduced graphene oxide, red circles: based on CVD graphene) and this work (red star). Scale bar, 10 μm (a).
Mentions: To determine the transport properties of the synthesized graphene films, back-gated graphene field effect transistors FETs were fabricated on 300 nm SiO2/Si substrates. The inset of Fig. 3a shows the schematic diagram and SEM image of the fabricated FETs. Highly reproducible transfer characteristics (IDS-VG) of the FETs measured at room temperature under ambient conditions. The typical IDS-VG curve measured at a VDS of 150 mV shows that the gate can cause either hole or electron conduction. The Dirac point of the FETs shifts slightly to a positive gate at VG ~ 25 V, demonstrating light p-type hole doping performance. According to the two slopes of the linear regions on both sides of the V-shaped curve, the hole mobility is μh ~ 496 cm2 V−1 s−1 and the electron mobility is μe ~ 676 cm2 V−1 s−1. As shown in Fig. 3b, the electron mobility of our water-dispersible graphene is much higher than that of graphene obtained by oxidation-reduction approaches25262728, and is also comparable to that of graphene films fabricated through high temperature CVD approaches2930313233343536373839. Considering that the spray coating progress is violent and inevitably introduces defects, impurities, wrinkles or overlaps, the performance of the FETs may be underestimated.

View Article: PubMed Central - PubMed

ABSTRACT

Despite significant progresses made on mass production of chemically exfoliated graphene, the quality, cost and environmental friendliness remain major challenges for its market penetration. Here, we present a fast and green exfoliation strategy for large scale production of high quality water dispersible few layer graphene through a controllable edge oxidation and localized gas bubbling process. Mild edge oxidation guarantees that the pristine sp2 lattice is largely intact and the edges are functionalized with hydrophilic groups, giving rise to high conductivity and good water dispersibility at the same time. The aqueous concentration can be as high as 5.0 mg mL−1, which is an order of magnitude higher than previously reports. The water soluble graphene can be directly spray-coated on various substrates, and the back-gated field effect transistor give hole and electron mobility of ~496 and ~676 cm2 V−1 s−1, respectively. These results achieved are expected to expedite various applications of graphene.

No MeSH data available.


Related in: MedlinePlus