Managing the degree of exfoliation and number of graphene layers using probe sonication approach

ABSTRACT

We have demonstrated a fast, versatile, and scalable approach to synthesize high-quality few layer graphene sheets with low defect ratio and high crystallinity produced from exfoliation of graphite flakes in DMF by using probe sonication. The effect of sonication time on degree of exfoliation and number of graphene layers has been fully investigated. The degree of exfoliation of graphene sheets as a function of sonication time has been successfully analyzed by XRD, UV-Vis spectroscopy, TEM, and BET studies. The morphological changes at different sonication times have also been observed by SEM. A structural and defect characterization of graphene sheets has been discussed in detail by Raman spectroscopic technique. The shift in position of 2D Raman band and its de-convolution provided information about formation of multi to few layer graphene sheets with sonication. Moreover, Raman results are highly consistent with TEM studies as per number of graphene layers is concerned.

KEYWORDS:

• Graphite flakes
• Graphene
• Liquid phase exfoliation
• Probe sonication

Acknowledgements

Financial support from UGC (University Grants Commission) is highly acknowledged. We are thankful to UGC-UPE and DST-FIST for providing Raman Spectrophotometer, XRD, TEM, BET, SEM, and UV-Visible spectrophotometer facilities.