J. Electrochem. Sci. Technol., 2021, 12(2), 167-172 - 167 - Improved Surface Plasmon Resonance Sensing Sensitivity due to an Electrochemically Potential-Induced Gold Reconstruction Baeck B. Choi 1,2 *, Bethy Kim 3 , Yiqi Chen 1 , and Peng Jiang 1 * Department of Chemical Engineering, University of Florida, Gainesville, FL 32611 USA Energy and Environment Laboratory, Korea Electric Power Corp. Research Institute, Daejeon, 34056 Korea Department of Chemistry, University of Florida, Gainesville, FL 32611 USA ABSTRACT The progressively improved sensing sensitivity (Δλ /∆n, nm/RIU) to detect the refractive index is observed on the SPR platform of an Au-covered epoxy gratings in an increase in potential cycling in a typical three-electrode cell. Here, a DVD- R optical disc was used as a structure template to prepare an Au-covered epoxy gratings, and the newly formed reverse track pitch structure on the epoxy substrate was used as a working electrode directly in aqueous sulfuric acid solution. It is expected that Au reconstruction by potential cycling in sulfuric acid electrolyte increases the packing density of Au atoms in the grain boundary and improves the propagation of electromagnetic waves. Keywords : Surface Plasmon Resonance, SPR, Au Reconstruction, Sensitivity Received : 23 December 2020, Accepted : 20 January 2021 1. Introduction Being highlighted label-free surface plasmon reso- nance (SPR) optical sensor uses modulation of the light output spectrum caused by locally modulated refractive index (localized surface plasmon reso- nance (LSPR)) [1-3]. For example, there is wave- length, angular distribution, intensity, phase, or polarization of the light output. Using a nanostruc- tured grating coupler instead of using a large and complex prism-based platform (e.g., Kretschmann or Otto configurations) has the advantage of being sim- ple and capable of scaling up. Nanostructured grating coupler is also being able to successively compensate the different wave-number between surface plasmon polaritons (SPPs) and external light. SPP is generated at an interface between metal and dielectric [4,5]. As a result, nanostructure-based grating couplers can successfully expand the practicality of plasmon sen- sors in a wide range of biosensors, photocatalytic, and heterogeneous catalytic researches [6-8]. In recent years, efforts have been made to develop nanostructure-based SPR platforms with high sensi- tivity (∆λ SPR /∆n, nm/RIU) and figure of merits (FOM, (∆λ SPR /∆n)/∆λ, 1/RIU) in particular, in terms of easy scalability, feasible implementation, and low cost [4]. Due to the narrow bandwidth of the wave- length consumed by the excitation of the surface plasmons, a high FOM with a narrow full width half maximum (FWHM, nm) in the optical spectrum allows the resonance to be observed more clearly through an effective and accurate sensing process. For SPR to expand its application to various environ- mental conditions, the physical and chemical resis- tance of each component of the SPR platform as well as the SPR detection parameters with high SPR sens- ing sensitivity is important. Various bottom-up and top-down approaches have been taken for this strat- egy, and our research group has previously reported a highly sensitive SPR detection platform based on the track pitch structure of commercial optical discs such as CD, DVD and Blu-ray [6,9]. By applying a com- mercial optical disc as an SPR platform, it is possible to easily produce a large, scalable area with a simple and economically beneficial preparation method. The sum of the binding energies of the surface Communication *E-mail address: b.choi@kepco.co.kr, pjiang@che.ufl.edu DOI: https://doi.org/10.33961/jecst.2020.01767 This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.