Abstract
Liquid-based bio-applications of graphene require a quantitative understanding of the graphene-liquid interface, with the surface charge density of adsorbed ions, the interfacial charge transfer resistance, and the interfacial charge noise being of particular importance. We quantified these properties through measurements of the zero-bias Faradaic charge-transfer between graphene electrodes and aqueous solutions of varying ionic strength using a reproducible, low-noise, minimally perturbative charge measurement technique. The measurements indicated that the adsorbed ions had a negative surface charge density of approximately −32.8 mC m−2 and that the specific charge transfer resistance was 6.5 ± 0.3 MΩ cm2. The normalized current noise power spectral density for all ionic concentrations tested collapsed onto a 1/fα characteristic with α = 1.1 ± 0.2. All the results are in excellent agreement with predictions of the theory for the graphene-solution interface. This minimally perturbative method for monitoring charge-transfer at the sub-pC scale exhibits low noise and ultra-low power consumption (∼fW), making it suitable for use in low-level bioelectronics in liquid environments.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.