Next Article in Journal
Effective Modulation of Optical and Photoelectrical Properties of SnS2 Hexagonal Nanoflakes via Zn Incorporation
Previous Article in Journal
Paper-Cut Flexible Multifunctional Electronics Using MoS2 Nanosheet
Article Menu

Export Article

Open AccessArticle

Unique Constant Phase Element Behavior of the Electrolyte–Graphene Interface

Lane Department of Computer Science and Electrical Engineering, West Virginia University, Morgantown, WV 26506, USA
Author to whom correspondence should be addressed.
Nanomaterials 2019, 9(7), 923;
Received: 6 May 2019 / Revised: 23 May 2019 / Accepted: 29 May 2019 / Published: 27 June 2019
PDF [2991 KB, uploaded 27 June 2019]


We report a unique constant phase element (CPE) behavior ( 1 Z = Q 0 ( j ω ) α ) of the electrolyte–graphene interface with both Q 0 and α showing dependence on the gate voltage. The frequency response of the electrolyte–graphene interface was studied using electrochemical impedance spectroscopy (EIS). The result suggests that (1) the electrolyte–graphene interface should be characterized as a CPE ( α < 1), rather than an ideal capacitor; and (2) both Q 0 and α show ambipolar dependence on the applied voltage. We speculate that the CPE behavior of the electrolyte–graphene interface arises from the charged impurities on the substrate and the defects in the graphene lattice, which could introduce inhomogeneity of local density of states (DOS). The low density of states of graphene makes α sensitive to these local DOS near the Dirac point, and thus showing dependence on the gate voltage. Measurement of the electrolyte–graphene interface capacitance based on multi-frequency capacitance-voltage (CV) profiling was demonstrated, and the extraction of the carrier mobility was performed. The study could lead to a more accurate understanding of the capacitive behavior of the electrolyte–graphene interface, which is instructive for the design and analysis of devices involving the electrolyte–graphene interface for nanoelectronics and bioelectronics applications. View Full-Text
Keywords: electrolyte–graphene interface; constant phase element; frequency response electrolyte–graphene interface; constant phase element; frequency response

Graphical abstract

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Supplementary material


Share & Cite This Article

MDPI and ACS Style

Sun, J.; Liu, Y. Unique Constant Phase Element Behavior of the Electrolyte–Graphene Interface. Nanomaterials 2019, 9, 923.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Nanomaterials EISSN 2079-4991 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top