An atomic-scale fluidic diode based on hexagonal nanopores in bilayer molybdenum disulfide

Nanofluidic diodes with nanochannels are of fundamental importance in many applications, e.g., logic gates, biosensors, and other advanced technologies. However, as the need arises for chip laboratories, miniaturization of nanofluidic channels has become increasingly prominent. Extensive research works have shown that atomic thickness molybdenum disulfide pores exhibit ultra-high permeability. Here, we performed molecular dynamics simulations to investigate the transport of water molecules and ions through a bilayer hexagonal nanopore of 2H-phase molybdenum disulfide (2H-MoS2). Our results demonstrate that the nanopore exhibits exceptional ion rectification and fluidic rectification, functioning effectively as an atomic-scale nanofluidic diode. The origin of these unique properties lies in the asymmetric atomic arrangement of the bilayer 2H-MoS2 nanopore, which generates oppositely polarized regions within the pore. This asymmetric polarization mirrors the essential characteristics of a bipolar diode. Moreover, the electric field drives ions to drag water molecules in a directional motion in the electrolyte solution, enhancing the nanopore's rectification behavior.