Optical Characteristic Measurement of Micro/Nanodroplet on Embedded Grating Nanostructure for Digital Microfluidic’s Electrode

Abstract

This report describes the potential design of an optical sensor system, in which the localized surface plasmon resonance (LSPR) type was used, coupled with digital microfluidic (DMF) technology. To achieve this potential design, a dielectric material was layered on top of a metal grating nanostructure so that the nanostructure was embedded in the dielectric matrix. Then, a hydrophobic layer was stacked on top of the dielectric layer for micro/nanodroplet movement. Sensitivity and figure of merit (FoM) parameters were analyzed to evaluate this potential design. In this research, various kinds of metal were investigated, and it was found that a gold grating nanostructure embedded inside the SiO2 dielectric matrix with Teflon AF2400 as hydrophobic layer gave the optimum sensitivity. However, the iron grating nanostructure embedded inside the SiO2 dielectric matrix with Teflon AF2400 as hydrophobic layer gave the optimum FoM of 1.481. Furthermore, noble metal grating nanostructures embedded inside a dielectric layer produce higher photoelectric conversion and current density values than other types of metals that are usually used, such as aluminum, cobalt, iron, copper, etc.INDEX TERMS digital microfluidic, embedded grating nanostructure, figure of merit, localized surface plasmon resonance, sensitivity.