Ten Years of Liquid-phase Exfoliation of Layered Crystals - A Bright Future ahead?

Layered materials are an abundant source of new nanostructures when thinned down to display fascinating layer number-dependent properties due to quantum confinement in two dimensions. About ten years ago, it was first demonstrated that layered crystals can be exfoliated down to monolayers in the liquid phase by a relatively simple and scalable methodology termed liquid-phase exfoliation that is widely applicable to many structures. By now, >10 classes of layered materials have been made accessible as two-dimensional nanosheets by this technique. In this article, advancements in exfoliation, size selection and characterisation are summarised. Remaining challenges, open questions and perspectives are also discussed.