Dual-Side Fabrication of Nanopores on Bilayer Graphene Membranes for Selective Ion Transport

Nanoporous graphene membranes with excellent ion and water filtration capabilities show great potential in applications, such as ion sieving and seawater desalination. However, one of the key challenges is to fabricate high-density, tunable subnanometer pores on two-dimensional membranes with high mechanical strength. Here we propose a facile process that leverages simple operations of convenient dual-side oxygen plasma treatment for fabrication of high-density nanopores on bilayer graphene membranes. Our experimental results manifest that the ion selectivity of bilayer graphene nanopores generated by the dual-side etching of oxygen plasma is 78%, which is comparable to that of the monolayer graphene nanopores. Furthermore, molecular dynamics simulations demonstrate that dual-side oxygen plasma treatment can create through-nanopores on the bilayer graphene membrane, while single-side oxygen plasma treatment only creates blind nanopores due to the anisotropic etching effect of oxygen plasma treatment.