Integrated ionic sieving channels from engineering ordered monolayer two-dimensional crystallite structures

Atomically thin solid-state channels enabling selective molecular transport could potentially be used in a variety of separation and energy conversion applications. The density of channels, their height, distance and edge structure are the key factors that dramatically impact the selective transport performance. However, such channels with small constrictions and atomic precision have been limited to proof-of-concept demonstrations based on microscale two-dimensional (2D) crystal stripes. Here, we report the engineering of highly ordered, scalable monolayer graphene crystallite arrays by chemical vapor deposition (CVD) method with a modified anisotropic etching approach. The size, shape, distance and edge structure of the graphene crystallite arrays in a large area could be delicately controlled through tailoring the synthetic parameters. This array structure can act as pillars to prop up a smooth single-crystal graphene film, and the fabricated integrated angstrom-size (3.4 Å) channels allow water transport but exclude hydrated ions, demonstrating potential in selective ionic sieving and nanofiltration practice.