Fig. 3. Trends of the I–V features in asymmetric tip–bulk KCl concentrations. The I–V curves of the 60 nm nanopipette in the following C _tip–C _bulk concentration combinations: (a) common low tip conc. (b) Common low bulk conc. (c) Common high tip conc. (d) Common high bulk conc. The scan rate is 100 mV s^–1. The inset shows the shift in the cross-point w.r.t. the origin (0,0). Each curve was collected after multiple scans until the last five repeated scans overlapped, confirming that a stable concentration gradient was established.