Van der Waals thin-film electronics

The development of emerging applications based on large-area flexible and wearable devices requires solution-processable thin-film electronics. Organic semiconductors can be processed in solution, but typically suffer from relatively low performance and insufficient stability in ambient conditions. Inorganic nanostructures, however, can be processed in solution while retaining the excellent electronic performance and structural stability of crystalline inorganic materials. In particular, a range of two-dimensional inorganic nanosheets can be dispersed in various solvents as stable colloidal inks. These nanosheets can be assembled into continuous thin films in which neighbouring sheets interact via van der Waals forces with few interfacial trapping states. The resulting tiled nanosheets, which we term two-dimensional van der Waals thin films, offer significant potential in thin-film electronics. Here we explore the development of van der Waals thin films and their use in high-performance largearea electronics. We examine the formulation of the nanosheet inks and their scalable assembly into van der Waals thin films and devices. We also consider their application in large-area wearable electronics and the challenges that exist in delivering practical devices.