Electrons on the surface of 2D materials: from layered electrides to 2D electrenes

The unique properties of 2D materials have motivated the discovery of new atomically thin materials that push the boundaries of synthetic design and device performance. One new class of 2D materials is the atomically thin form of layered electrides, which consist of alternating layers of atoms and electrons. We call these ultrathin electrides, “electrenes”. Electrenes possess exciting properties like high mobility, high carrier concentrations, and low work functions. In this review, we discuss the mechanical, electronic, optical, and chemical properties of electrenes and their bulk layered crystals. We highlight strategies for the synthesis of electrenes and conclude with potential applications, including catalysis, batteries, and transparent conductors.