Alumina Membrane with Hour-Glass Shaped Nanochannels: Tunable Ionic Current Rectification Device Modulated by Ions Gradient

Figure 4

Ionic transport properties of the hour-glass shaped alumina nanochannels measured in 1 mM KCl solution with pH gradient stimuli. (a) 𝐼-𝑉 curves with pH_L 4.5 and pH_R varying from 4.5 to 11.0. (b) 𝐼-𝑉 curves with pH_R 10.5 and pH_L varying from 3.6 to 10.5. (c) and (d) schematic representation of the surface charge distribution under symmetric/asymmetric pH stimuli.

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