2D metal oxide nanoflakes for sensing applications: Review and perspective

In this review the state of the art and future prospects of 2-dimensional (2D) metal oxide nanoflakes used as active sensing elements for the detection of solutes, gases and radiation are discussed. 2D material geometries are particularly interesting for sensing applications because they provide large specific surface areas and are suitable for crystal facet engineering. In addition, unique material properties of atomically thin nanosheets due to quantum size effects provide engineering possibilities beyond the realm of their bulk counterparts. A variety of possibilities in materials, synthesis routes, (hierarchical) sensor architectures and application areas is sketched. The discussion is focused on high-performing sensors and innovative concepts. The scope is limited to nanoflakes with a thickness of up to 50 nm. Special attention is given to sensing based on material properties that are unique to atomically thin nanosheets.