Solution-based 'bottom-up' synthesis of group VI transition metal dichalcogenides and their applications

Abstract

Research interest in the area of transition metal dichalcogenide (TMD) nanostructures has significantly increased in recent years. This interest is driven by their exceptional properties (e.g. semiconductor state, electronic confinement, conductivity, flexibility, transparency, large surface area, etc.) and their potential applications as materials for catalysis, photonics, sensing, solid lubrication, energy storage, high performance electronics, imaging, medical diagnostics and drug delivery systems, to name a few. The most common methods of production of these nanomaterials are ‘‘top-down’’ techniques involving solution-phase exfoliation or mechanical microcleavage, or chemical vapour deposition, a ‘‘bottom-up’’ approach. However, these methods suffer from a number of drawbacks, including poor controllability over size, high cost, and lack of scalability, thus limiting their potential commercial use. Therefore, over the last number of years, solution-based ‘‘bottom-up’’ synthesis of TMDs is gaining much attention as it can provide solutions to these problems. This review focuses on ‘‘bottom-up’’ methods such as hydro/ solvothermal, hot-injection and other approaches which have the potential to produce high-quality TMD nanostructures with controllable properties such as size, phase, morphology, and at low-cost. Here, we consider and compare various ‘‘bottom-up’’ synthetic techniques for synthesis of TMD nanostructures, explore some potential applications of corresponding colloidal TMD materials and provide future outlook for this fast- developing and important area.