Graphite–MoS₂ composite thin films with photoconductivity synthesized using liquid interface assembly

Solution fabrication of large-area thin films with 2D materials is an active field of study. In this work, we disperse natural graphite and MoS₂ flakes at a heptane–water interface. Individual flakes spread out and arrange themselves as a thin film at the interface, which is then transferred to a glass substrate. This technique allows us to combine the light absorbing properties of MoS₂ with the high conductivity of graphite to make composite films which exhibit photoconductivity. We observe that the flakes like to arrange themselves in a single layer and resist stacking. The conductivity of the resulting film is correlated with its porosity, much like a percolation network of resistors. While the technique is effective in spreading out 2D materials into a single layer, we do not observe evidence of exfoliation at the atomic scale.