Electrochemical Semiconductor Analysis By Square Wave Voltammetry
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2020-05-01 |
| Journal | ECS Meeting Abstracts |
| Authors | Bojan Miljkovic, Harry E. Ruda |
| Institutions | University of Toronto |
Abstract
Section titled âAbstractâStudies in the past 20 years have utilized cyclic voltammetry (CV) for determining various electronic properties (e.g. density of states, electron carrier concentrations, trap state capacitances) of semiconducting titanium oxide films in photoelectrocatalytic systems such as dye-sensitized solar cells [1-4]. Though primarily used for redox sensing, this work presents square wave voltammetry (SWV) as an alternative to determining said properties. As an electrochemical characterization technique, SWV can provide significantly less background current and greater sensitivity than CV [5]. This is beneficial for the accurate measurement and calculation of electronic properties from electrochemical semiconductor current-voltage data. By varying the applied frequency as well as step and/or pulse sizes of the square wave, one can probe electronic processes of various time scales, in contrast to CV which only allows control of the potential scanning rate across the same potential window [5, 6]. This work presents a comparative study of electronic properties as determined by SWV versus CV for various semiconducting electrodes such as silicon, germanium, titanium oxide, and doped diamond films. This technique was also extended to semiconductor heterostructures - such as noble metal-decorated titanium oxide - for observation of intraband gap states and their contribution to the overall electronic properties of the electrode as determined by SWV. [1] Liu, B. et. al., âIntrinsic intermediate gape states of TiO 2 materials and their roles in charge carrier kineticsâ, J. Photochem. and Photobio. C: Photochem. Rev., 39 (2019) 1-57 [2] Zare, M., Mortezaali, A., and Shafiekhani, A., âPhotoelectrochemical determination of shallow and deep trap states of platinum-decorated TiO 2 nanotube arrays for photocatalytic applicationsâ, J. Phys. Chem. C, 120 (2016) 9017-9027 [3] Fabregat-Santiago, F. et al., âHigh carrier density and capacitance in TiO 2 nanotube arrays induced by electrochemical dopingâ, J. Am. Chem. Soc., 130 (2008), 11312-11316 [4] Abayev, I. et al., âProperties of the electronic density of states in TiO 2 nanoparticles surrounded with aqueous electrolyteâ, J. Solid State Electrochem, 11 (2007) 647-653 [5] Mirceski, V. et al., âSquare-wave voltammetry: A review on the recent progressâ, Electroanalysis , 25 (2013) 2411-2422 [6] Bard, A. J. and Faulkner, L. R., Electrochemical Methods: Fundamentals and Applications, 2 nd ed. Hoboken, NJ: John Wiley & Sons, Inc., 2001.