2D Heterostructure for Enhanced Gas Barrier Performance via Synergetic Effect

Abstract

We report the dramatically enhanced gas barrier performance of polycrystalline monolayer graphene (PCG) film by the construction of 2D heterostructure with polycrystalline multilayered hexagonal boron nitride (PCMB) film, while maintaining high optical transmittance of 96.2 % at 550 nm. 2D heterostructure on flexible polyethylene terephthalate (PET) film is simply fabricated via a sequence transfer of PCMB and PCG grown by chemical vapor deposition (CVD). Water vapor transmission rate (WVTR) of individual PCG and PCMB films grown by chemical vapor deposition (CVD) exhibit 2.02 and 1.96 g/m2·day, respectively, which is a slight improvement compared to that of bare PET substrate (2.16 g/m2·day) due to the imperfection of their crystal structure. In sharp contrast, 2D heterostructure consisted of PCG on PCMB shows almost 30 times lower WVTR value (0.07 g/m2·day) compared to that of PET substrate, which is the lowest reported value among CVD-grown 2D materials. The water vapor is impermeable in PCG stacked on thick and high-quality hBN grains, whereas water vapor only penetrates through structural defects such as grain boundaries or point defects in PCG on the grain boundaries of PCMB.