EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Center for Materials Research, Justus Liebig University Giessen, Heinrich-Buff-Ring 17, 35392 Giessen, Germany

Porous thin films from liquid exfoliated WS2 2D nanosheets
2D transition metal dichalcogenides (TMDs) are emerging semiconductors of great interest for a number of applications, ranging from (opto)electronics to biomedicine. Liquid exfoliation is a highly scalable method for producing colloidal suspensions of TMDs 2D nanosheets starting from bulk crystalline powders. The resulting inks can be used for solution processing/printing of thin films or other solid structures, paving the way to implementation in low-cost commercial products. In this contest, the possibility to achieve porous thin films from liquid exfoliated 2D TMDs emerges as an interesting perspective to produce electrode/capacitor architectures to be integrated, for example, in energy storage devices.
We report here on the liquid phase exfoliation of WS2 in a range of solvents (including “green” ones like isopropanol and water) employing both shear mixing and tip sonication, which allows to make fair comparisons among the different conditions and to define which yields the best results in terms of 2D nanosheets average thickness and quantity. Characterization is carried out employing a combination of spectroscopic and microscopy techniques, providing a full picture of the obtained inks. We also report on a templating method to obtain porous thin films from these colloids, which are also characterized in terms of crystallinity, morphology and surface area/pores distribution. Similar scaffolds hold great promises to be applied in photo-capacitor systems and the functionalities in this direction are currently under investigation.