Higher Ultrasonic Frequency Liquid Phase Exfoliation Leads to Larger and Monolayer to Few-Layer Flakes of 2D Layered Materials

Madina Telkhozhayeva, Eti Teblum, Rajashree Konar, Olga Girshevitz, Ilana Perelshtein, Hagit Aviv, Yaakov R. Tischler, Gilbert Daniel Nessim

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

Among the most reliable techniques for exfoliation of two-dimensional (2D) layered materials, sonication-assisted liquid-phase exfoliation (LPE) is considered as a cost-effective and straightforward method for preparing graphene and its 2D inorganic counterparts at reasonable sizes and acceptable levels of defects. Although there were rapid advances in this field, the effect and outcome of the sonication frequency are poorly understood and often ignored, resulting in a low exfoliation efficiency. Here, we demonstrate that simple mild bath sonication at a higher frequency and low power positively contributes to the thickness, size, and quality of the final exfoliated products. We show that monolayer graphene flakes can be directly exfoliated from graphite using ethanol as a solvent by increasing the frequency of the bath sonication from 37 to 80 kHz. The statistical analysis shows that ∼77% of the measured graphene flakes have a thickness below three layers with an average lateral size of 13 μm. We demonstrate that this approach works for digenite (Cu9S5) and silver sulfide (Ag2S), thus indicating that this exfoliation technique can be applied to other inorganic 2D materials to obtain high-quality few-layered flakes. This simple and effective method facilitates the formation of monolayer/few layers of graphene and transition metal chalcogenides for a wide range of applications.

Original languageEnglish
Pages (from-to)4504-4514
Number of pages11
JournalLangmuir
Volume37
Issue number15
DOIs
StatePublished - 20 Apr 2021

Bibliographical note

Publisher Copyright:
© 2021 The Authors. Published by American Chemical Society.

Funding

This research was partially funded by the European Commission through the project ADMAIORA (Advanced nanocomposite MAterIals fOr in situ treatment and ultRAsound-mediated management of osteoarthritis), funded in the Horizon 2020 framework, grant agreement 814413 ( https://www.admaiora-project.com/ ).

FundersFunder number
Horizon 2020 framework
Horizon 2020 Framework Programme814413
European Commission

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