Identification of mechanically exfoliated graphene and applications of graphene impermeability

Abstract

Two-dimensional (2D) materials have unique properties compared with the traditional materials. Graphene, as one of the most fundamental 2D materials, was first isolated by mechanical exfoliation in 2004. This work also led to Nobel Prize in Physics in 2010 for the researchers. Graphene exhibits many significant properties, including high carrier mobility, remarkable mechanical properties, high light transmittance and large thermal conductivity. The defects intensities related issues of graphene deeply influence the exfoliation of graphene nanosheets and impermeability. In this thesis, we design two experiments which related to the graphene defects densities: (a) A theoretical model of mechanically exfoliated graphene size distributions identification and comparison with the experimental statistics results; (b) Improved air-stability of organic-inorganic perovskite with anhydrously transferred graphene We first develop a theoretical simulation model about the mechanical process and the size distributions of the tape-assisted graphene mechanical exfoliation. In addition, we compare the simulation results with the experiment results to confirm the validity of this theoretical model. In addition to the size distribution identification of mechanically exfoliated graphene, the impermeability of graphene layer is also related to the defects density. Perovskite films are successfully protected by graphene barrier to the moisture. The improved stability is resulted from the protection of graphene impermeability properties.