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Dual frequency ultrasonic liquid phase exfoliation method for the production of few layer graphene in green solvents

Kaur, Amanpreet; Morton, Justin A.; Tyurnina, Anastasia V.; Priyadarshi, Abhinav; Ghorbani, Morteza; Mi, Jiawei; Porfyrakis, Kyriakos; Eskin, Dmitry G.; Tzanakis, Iakovos


Amanpreet Kaur

Justin A. Morton

Anastasia V. Tyurnina

Abhinav Priyadarshi

Morteza Ghorbani

Kyriakos Porfyrakis

Dmitry G. Eskin

Iakovos Tzanakis


In this work, we implement a dual frequency (24 kHz and 1174 kHz) ultrasonic assisted liquid phase exfoliation (ULPE) technique in deionized water (DIW) and other eco-friendly solvents, to produce a variety of high-quality few-layer graphene (FLG) solutions under controlled ultrasonication conditions. The resulting FLG dispersions of variable sizes (∼0.2–1.5 μm2) confirmed by characterisation techniques comprising UV–Vis spectroscopy, Raman spectroscopy and high-resolution transmission electron microscopy (HR-TEM). For the first time we demonstrate that high yield of FLG flakes with minimal defects, stable for 6 + months in a solution (stability ∼ 70 %), can be obtained in less than 1-hour of treatment in either water/ethanol (DIW:EtOH) or water/isopropyl alcohol (DIW:IPA) eco-friendly mixtures. We also scrutinized the underlying mechanisms of cavitation using high-speed imaging synchronized with acoustic pressure measurements. The addition of ethanol or IPA to deionized water is proposed to play a central role in exfoliation as it regulates the extend of the cavitation zone, the intensity of the ultrasonic field and, thus, the cavitation effectiveness. Our study revealed that lateral sizes of the obtained FLG depend on the choice of exfoliating media and the diameter of a sonotrode used. This variability offers flexibility in producing FLG of different sizes, applicable in a wide spectrum of size-specific applications.


Kaur, A., Morton, J. A., Tyurnina, A. V., Priyadarshi, A., Ghorbani, M., Mi, J., …Tzanakis, I. (2024). Dual frequency ultrasonic liquid phase exfoliation method for the production of few layer graphene in green solvents. Ultrasonics Sonochemistry, 108, Article 106954.

Journal Article Type Article
Acceptance Date Jun 12, 2024
Online Publication Date Jun 14, 2024
Publication Date Aug 1, 2024
Deposit Date Jun 26, 2024
Publicly Available Date Jun 27, 2024
Journal Ultrasonics Sonochemistry
Print ISSN 1350-4177
Electronic ISSN 1873-2828
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 108
Article Number 106954
Keywords Few-layer graphene; Acoustic pressure; Ultrasonic exfoliation; Eco-friendly solution; Shock wave emission
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