Nanocrystalline diamond microelectrode on fused silica optical fibers for electrochemical and optical sensing

At a Glance

Metadata	Details
Publication Date	2015-07-01
Journal	Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE
Authors	Robert Bogdanowicz, Michał Sobaszek, Mateusz Ficek, Marcin Gnyba, Jacek Ryl
Institutions	Institute of Fluid Flow-Machinery, Warsaw University of Technology
Citations	2

Abstract

Fabrication process of thin boron-doped nanocrystalline diamond (B-NCD) microelectrode on fused silica single mode optical fiber has been investigated. The B-NCD films were deposited on the fibers using Microwave Plasma Assisted Chemical Vapor Deposition (MW PA CVD) at glass substrate temperature of 475 ºC. We have obtained homogenous, continuous and polycrystalline surface morphology with the mean grain size in the range of 100-250 nm and high sp<sup>3</sup> content in B-NCD films. The films deposited on glass reference samples exhibit high refractive index (<i>n</i>≈2.05 at λ=550 nm) and low extinction coefficient. Furthermore, cyclic voltammograms (CV) were recorded to determine the electrochemical window and reaction reversibility at the B-NCD fibre-based electrode. Cyclic voltammetry (CV) measurements in aqueous media consisting of 5mM K3[Fe(CN)6] in 0.1M Na2SO4 demonstrated a width of the electrochemical window up to 2.5 V and relatively fast kinetics expressed by a redox peak splitting below 500 mV. Moreover, thanks to high-n B-NCD overlay, the coated fibers can be also used for enhancing sensitivity of long-period gratings (LPGs) induced in the fibers. The LPG is capable for measuring variations in refractive index of surrounding liquid by tracing shift in resonance appearing in transmitted spectrum. Possible combined CV and LPG-based measurements are discussed in this work.

Tech Support

Original Source

DOI: https://doi.org/10.1117/12.2185154

References

2003 - Optically Transparent Diamond Electrodes for UV-Vis and IR spectroelectrochemistry