A team of scientists from the National University of Singapore has successfully developed a method to chemically exfoliate molybdenum disulfide crystals into high quality monolayer flakes, with a higher yield and larger flake size than current methods. These flakes can then be made into a printable solution, which can be applied in printable photonics and electronics.
The researchers explored the metal adducts of naphthalene. They prepared naphthalenide adducts of lithium, sodium, and potassium, and compared the exfoliation efficiency and quality of molybdenum disulfide generated. Using a two-step expansion and intercalation method, they were able to produce high quality single-layer molybdenum disulfide sheets with unprecedentedly large flake size.
They also demonstrated that the exfoliated molybdenum disulfide flakes could be made into a printable solution, and wafer-size films can be printed, as the good dispersion and high viscosity of the flakes render it highly suitable for inkjet printing.
The fast growing field of printed photonics, electronics, and optoelectronics demands high material quality, precise material deposition, and application-specific optical, electrical, chemical, and mechanical properties.
The researchers plan to continue developing inks based on different types of two-dimensional chalcogenides exfoliated by their novel method so as to produce printable optoelectronic devices. They will also be testing the optical non-linear properties of the flakes they have produced.