Synergistic modulation of ionic selectivity in graphene pores modified by crown ether

Achieving high ion selectivity in atomically thin membranes represents a critical step toward advanced gating-controlled ionic transport in nanofluidic applications such as logic gates and biosensors. Herein, monolayer graphene pores modified by crown ether are constructed to systematically investigate the ion selectivity in both vacuum and aqueous environments from a theoretical perspective. Synergistic optimization of charge distribution and pore size significantly improves the ion selectivity, showing a cation/anion selectivity ratio of up to 10^2. The energy profiles for ion penetration (e.g., Li^+, Na^+, K^+, Cl^-, Br^-) are modulated by tailoring the pore size and introducing charges, as validated by kinetic analysis of ion-free diffusion and electroosmotic flow. The fundamental ion-sieving mechanism is further elucidated by examining the dependence of ion currents on carrier concentration in the nanopores. These findings on ion transport pave the way for artificial nanochannel membrane applications in nanofluidic circuits and biomimetic sensors.