Polymer Stamp-Based Mechanical Exfoliation of Thin High-Quality Pyrolytic Graphite Sheets

Abstract

This paper reports on a polymer stamp-based mechanical exfoliation method for producing thin (<1 μm) graphite sheets from a highly ordered pyrolytic graphite (HOPG) source by tailoring key exfoliation process parameters, utilizing in-plane shear oscillation during exfoliation, and controlling the thickness of a polydimethylsiloxane (PDMS) stamp. Experiments on the effect of high frequency in-plane shear oscillation and the effect of PDMS stamp thickness are designed to reduce the thickness of exfoliated layers and to minimize surface morphological variations. Results show that the exfoliated sheets consist of a range of layer thicknesses, surface areas, and surface morphological features. The exfoliated HOPG sheets are also found to be thinner, more electrically and thermally conductive, and of higher quality than commercially available pyrolytic graphite sheets.