Atomic-scale ion transistor with ultrahigh diffusivity

Gated ion flow in graphene oxide membranes Cells are adept at fast, gated ion flow through tailored channels, which is key to many biological processes. Xue et al. developed ion transistors from reduced graphene oxide membranes and observed a field-enhanced diffusivity of the ions (see the Perspective by Hinds). By applying electrical gating, the average surface potential on the graphene layer could be controlled, thus altering the energy barrier for ion intercalation into the channel and leading to very high diffusion rates. The authors observed selective ion transport two orders of magnitude faster than the ion diffusion in bulk water. Science , this issue p. 501 ; see also p. 459