Group IVB transition metal trichalcogenides: a new class of 2D layered materials beyond graphene

The discovery of graphene, a single atomic layer of carbon in a hexagonal lattice, has invigorated enormous research interests in two‐dimensional ( 2D ) layered materials and their one‐dimensional ( 1D ) derivatives not only owing to their extraordinary physical and chemical properties but also their high potential for applications in electronic and photonic devices. A weakness of the graphene however is its lack of a bandgap—a prerequisite for building field‐effect transistors ( FETs ). A stream of new 2D layered materials have been developed over the past 5 years, including, among many others, silicene, phosphorene, and transition metal dichalcogenides. Monolayers of many of these 2D materials exhibit a bandgap, either direct or indirect. In 2015, a new class of 2D layered materials, namely, group‐ IVB transition metal trichalcogenides ( TMTCs ), has been uncovered. A prototypical representative of this new class of 2D materials is TiS 3 whose monolayer is predicted to possess a direct band gap of about 1 eV [close to that (1.17 eV ) of bulk silicon], and relatively high carrier mobility. Isolation of the few‐layer TiS 3 sheets and TiS 3 nanoribbons via mechanical exfoliation has been realized in the laboratory in 2015. The modest 1‐ eV band gap, relatively high carrier mobility, as well as high chemical stability in open air render TiS 3 monolayer a promising 2D material for nanoelectronic and nanophotonic applications. In this study, we give an overview of the emerging area of 2D and 1D TMTC materials and suggest future research directions related to these novel materials. WIREs Comput Mol Sci 2016, 6:211–222. doi: 10.1002/wcms.1243 This article is categorized under: Structure and Mechanism > Computational Materials Science