Flow-Assisted Ultrasonic Exfoliation Enabling Scalable and Rapid Graphene Production for Efficient Inkjet-Printable Graphene Ink

Abstract

Achieving high efficiency in graphene production andprinting processsimultaneously is challenging, but it needs to be addressed as itis critical for realizing the commercial viability of printed graphenedevices. This study successfully substantiates these requirementsby significantly improving the efficiency of graphene production andsubsequently developing an inkjet-printable graphene ink that enablesthe rapid formation of the percolation network of graphene flakes.The integration of a flow coil reactor into an ultrasonic bath resultsin scalable and rapid graphene production, with graphene productivityup to three orders of magnitude higher than conventional liquid-phaseexfoliation (LPE), offering the potential that ultrasonic LPE canbenefit the scalability and simplicity of graphene production. Inaddition, the graphene ink, optimized by ink formulation, has a stablehigh graphene concentration of 3.5 g L-1, resultingin the formation of stable percolation networks of graphene flakesonly after two printing passes under optimized printing conditions.The printed graphene patterns are also confirmed to be conformableto various substrates and durable against repeated stretching andbending stress. By ensuring high efficiency in graphene productionand inkjet-printable ink preparation, this study would promote thecommercialization of graphene production and the resulting printedgraphene devices.