Steady-State Electrochemistry Isolates Electron Hopping from Counterion Diffusion-Migration in Planar MOF Films

25 June 2024, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


Current methods for measuring electron-hopping diffusion coefficients of planar metal-organic framework (MOF) films typically use transient potential-step experiments, assuming a simple diffusional response. However, these experiments induce a net flux of counter ions, resulting in an electric field and transport by electromigration, which can impair the accuracy of the measurement. To remedy this, we employ an alternative method based on steady-state cyclic voltammetry. By adding a mobile redox acceptor molecule to the electrolyte, the additional cross reaction between the film and the acceptor mimics a source-drain electrode configuration, generating a steady state with negligible counter ion flux. Additionally, we construct a bespoke physical model and derive an analytical expression to correct the current response for any electric field effects. Overall, this method effectively isolates the diffusional response from ionic diffusion-migration and electric field effects. We expect these results will improve the accuracy of experimentally determined electron-hopping rates of electroactive MOF films.


metal-organic frameworks
electron hopping
charge transport
cyclic voltammetry
continuum modeling

Supplementary materials

Johnson et al. Supporting Information
Experimental methods, summary of Poisson-Nernst-Planck theory applied to electron-hopping, physico-mathematical model and derivations, summary of parameters and symbols, film characterization, and further electrochemical experiments.


Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.