SPREAD FILMS OF SINGLE MOLECULAR TRANSITION-METAL SULFIDES

A novel technique for preparing large area, optical quality, thin films of transition-metal dichalcogenides such as MoS2 and WS2 on different substrates is described. The process has features akin to Langmuir-Blodgett film preparation, in that single molecular layers of disulphides are formed with polar and non-polar regions at a water/organic interface. This surfactant-like character of molecules is used to prepare highly oriented films at an interface. The films can then be transferred onto a substrate either by a conventional dipping method or by spontaneous spreading to produce optical quality, large-area uniform films of MoS2. A large class of new materials, hitherto unavailable, can be prepared in the form of thin films by including a variety of organic molecules between the layers of single molecular layers of MoS2 using the technique.