Hydrogen Optical Metamaterial Sensor Based on Pd Dendritic Nanostructures

Abstract

In this manuscript we present a new type of hydrogen optical metamaterial sensor based on the fabrication of Pd dendritic nanostructures. The fabrication of the sensor relies on a cheap self-assembly process based on the pulsed electrodeposition method in nanoporous alumina templates. By performing optical transmission measurements, we demonstrate how this sensor can monitor hydrogen gas concentrations at room temperature either by evaluating the rate of signal decay during the Pd hydrogen absorption (transient regime) or by measuring the total variation in signal once the system achieves the equilibrium state (stationary regime). We take into account the effects of the Pd-hydrogen phase transition and its size dependency to explain the kinetics of the hydrogen absorption and desorption in the studied samples. By using the transient detection method, the sensor is able to detect in approximately 50 s the explosive H 2 (g) concentration threshold of 4 % v/v at atmospheric pressure and room temperature.[a] MSc.

Molecular Plasmonics with Metamaterials

“…A variety of plasmonic metamaterial-based direct hydrogen sensors have been developed, including palladium nanohole arrays, , palladium nanowire arrays, , palladium nanohelix arrays, and metal–insulator–metal nanostructure-based perfect absorbers. ,− For example, in a palladium-based perfect absorber structure, an array of palladium nanowires stacked above a MgF 2 spacer layer separating it from a gold bottom mirror (Figure a) was used to ensure nearly zero transmission through the structure due to the strong coupling between the plasmon resonances in the nanowires and the image dipoles induced in the gold mirror. Upon exposure of the sensor to 1% and 4% H 2 in N 2 carrier gas, the sensor showed an obvious change in the reflectance (Figure a).…”