Principles for fabricating moisture barrier films via stacked Janus graphene layers.

Zhou, Chaofan; Gao, Hongjie; Bu, Saiyu; Wu, Haotian; Liang, Fan; Li, Fangfang; Hu, Zhaoning; Zhao, Yixuan et al. · Nat Commun · 2025

basic_science · Level V

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Abstract

The excellent impermeability makes graphene film an ideal candidate for thin film encapsulation technology. However, current chemical vapor deposition (CVD) graphene-based barrier films can not provide sufficient moisture barrier performance, suggesting a lack of understanding in mechanism that dominates water diffusion in/through graphene stacks. Herein, we fabricate large-area graphene barrier films with a record-low water vapor transmission rate (WVTR) of 5 × 10<sup>-5 </sup>g/(m<sup>2</sup>·day), two orders of magnitude lower than previous works, in which two stacked Janus graphene films are intercalated by toluidine blue O (TBO) sub-monolayer: one side of graphene is decorated with fluorine- and oxygen-containing groups to allow crack-free transfer, while the other side is functionalized with hydroxyl groups to trap water. The intercalated TBO further blocks water transport due to a strong water-TBO interaction. Our work opens a route for surface/interface engineering of CVD graphene and promises its exciting future in the applications for advanced packaging.