Environment friendly dual-frequency ultrasonic exfoliation of few-layer graphene

Ultrasound-aided liquid phase exfoliation (ULPE) of graphene in pure water is environment-friendly. Two limiting factors ULPE are the non-uniform thickness few-layer (FLG) and a relatively low yield. Here we describe that enables us to produce FLG flakes with 3 layers flake sizes exceeding 1 ?m 2 just h. This process based on using combination two ultrasound sources high frequencies: 1174 kHz 20 kHz. different frequencies generate wider population size distribution cavitation bubbles act through number mechanisms towards graphene. For first time was characterized by acoustic measurements. Results show yield (10%) can be achieved. study demonstrates use dual frequency ultrasonic source control pressure critical optimizing quality assisted LPE water. It suggested width peak reflecting shock-wave emissions used as an indicator completeness, opening for way in-situ monitoring process. • Few-layer exfoliated dual-frequency sonication High- low-frequency has synergetic effect flakes. A stages measurements demonstrated.