Shear-assisted liquid exfoliation is a primary candidate for producing defect-free two-dimensional materials from labs to industry. Diverse hydrodynamic conditions exist across production methods, and combined with low-throughput, high-cost characterization techniques, strongly contribute to the wide variability in performance and material quality. Through investigations on strikingly different flow regimes, and using graphene as the prototypical two-dimensional material, we find that scaling of production depends on local stress field distributions and precursor residence time. We report a novel indirect diffuse reflectance method to measure graphene concentration in real-time, using low-cost optoelectronics and without the need to remove the precursor material from the heterogeneous dispersions. We show that this high-throughput, in situ approach has broad applicability by controlling the number of atomic layers on the fly, rapidly optimising green solvent design for maximum yield, and viewing live production rates. Combining insights on the hydrodynamics of exfoliation with this scalable monitoring technique, targeted process intensification, quality control, batch traceability and individually customisable materials on-demand are possible.
This research has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 707340, and support from the EPSRC CDT in Advanced Characterisation of Materials (EP/L015277/1).
InstitutionUniversity of Birmingham
ORCID For Submitting Author0000-0003-2713-8889
Declaration of Conflict of InterestNo conflict of interest