Rectified Ion Transport in Ultra-thin Membrane Governed by Outer Membrane Electric Double Layer

of main observation and conclusion The outstanding combination of selectivity and permeability observed in ultra-thin nanoporous mem-branes atracts broad interest from both fundamental research and practical application aspects.t is reported that the asymmetrical ion transport can berealized through the modfication of polyelectrolytes on the outer membranes surface.However,the related mechanisms are til nclear which hinderstheir applications.Herein,we systematclly investigate the origin of the ion current rectification in heterogeneously charged ultra-thin nanopores.Thecalcuated resuts based on the contiuity model suggest that,the ion transport across the ulra-thin membrane is dominated by the charge on the outermembrane surfoce rather than the pore wal.the overlap of electric double layer outside the pore entrance is essential fpr the ion asymmetric transport.And t acordingly results in the fact that the ion concentration enrichment and depletion effect ocurring outside the nanopore orifices governs the highand low ionic conductance states under the applied bias.These features can be regulated by the membrane surface state,which is truly attractive be.Ccause the surfaces of the outer membrane can be easily modified by experimental approaches.These findings provide the renew inspiration for the design of high-performance 2D nanofluidic devices.