D. He, E. Madrid, B. D. B. Aaronson, L. Fan, J. Doughty, K. Mathwig, A. M. Bond, N. B. McKeown and F. Marken, ACS Applied Materials and Interfaces 9 (2017) 11272.
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A thin film of Nafion^®, of approximately 5 µm thickness, asymmetrically deposited onto a 6 µm thick film of poly(ethylene terephthalate) (PET) fabricated with a 5, 10, 20, or 40 µm microhole, is shown to exhibit prominent ionic diode behaviour involving cation charge carrier (“cationic diode”). The phenomenon is characterized via voltammetric, chronoamperometric, and impedance methods. Phenomenologically, current rectification effects are comparable to those observed in nano-cone devices where space-charge layer effects dominate. However, for microhole diodes a resistive, a limiting, and an over-limiting potential domain can be identified and concentration polarization in solution is shown to dominate in the closed state