Fabrication of graphene-based oragnic/inorganic hybrid multi-lauer and its application to thin film barrier

Abstract

Graphene is thought be a new candidate for water vapor barrier film because of its dens honeycomb structure of carbons with only one atom thick and high optical transmit-tance. However, the barrier property reported in previous researches is not good enough to be applied in organic electronic devices due to the nano-capillary effect between graphene layers and intrinsic, extrinsic defects on graphene plane. In this study, two separate approaches were tested to solve this issues and to use graphene as a barrier film material. One approach was using graphene oxide (GO) flake stacked with hydrophobic polymer alternately to block the water penetration and to prevent the formation of inter-layer capillary. The polymer was deposited via initiated chemical vapor deposition (iCVD) method, which offers a conformal coverage on a GO layer without any damage. The water vapor transmission rate (WVTR) of 2 dyads (polymer-GO layer 1 dyad) was measured to be as low as $10^{-1} g/m^2day$. The other approach is using chemical vapor deposition (CVD) graphene with aluminum ox-ide. The graphene defect sites have more reactivity than graphene surface, so it is possible that aluminum oxide film forms selectively on the defect sites via atomic layer deposition (ALD). The results of the deposition of aluminum oxide layer on a transferred CVD graphene was measured to be as low as $10^{-3} g/m^2day$. The results showed high potential of graphene as a moisture barrier film and further optimization could reduce the WVTR results.