One-step mechanical exfoliation and deposition of layered materials (graphite, MoS2, and BN) by vacuum-kinetic spray process

Abstract

The exfoliation of micron-layered materials to few-layered nanosheets is still a great challenge due to their widespread use in various applications. Herein, we provide a new approach for one-step mechanical exfoliation and deposition of graphite, MoS2, and boron nitride at room temperature. The essence of this technique is that the shock compaction wave produced by the micron powder impact with the hard substrate at a high velocity induces fragmentation and exfoliation of layered materials. The lattice expansion due to removal of stacked layers and reduction of crystalline domain size in nanosized thin films is identified using x-ray diffraction and a high-resolution transmission electron microscope. Raman spectra of the nanostructured thin film indicate the improvement of disorder-related modes due to the kinetic-induced layer separation and powder fragmentation. X-ray photoelectron spectra analysis indicates the transformation of bond configuration from sp2 hybridization of bulk hexagonal structure to sp3 in the nanostructured thin film.