Synthesis of large-scale transition metal dichalcogenide films and their applications in hydrogen production

Transition metal dichalcogenides (TMDCs) have been studied extensively for their attractive mechanical, electrical, optical, and electrochemical properties. A large scale synthesis of these materials in thin films down to monolayers with thickness control and high crystalline quality remains a major hurdle to utilize them in applications. In this talk, I will discuss our efforts to synthesize centimeter-scale thin films and heterostructures of TMDCs including tellurides such as WTe₂ and MoTe₂. I will discuss how the morphology and grain size of the thin films is intimately linked to the strain that builds during synthesis and ways to mitigate such strain. With our synthesized films, we explore thermal conductivity of WTe₂ thin films and aspects of hydrogen evolution reaction that is often overlooked, such as the Schottky barrier at the interface between the chalcogenide catalyst (for example MoS₂) and the electrode and the dielectric substrate effect. Finally, I will discuss the detrimental surface oxidation effect on the transport properties of the TMDCs, which must be overcome for large-scale applications.