Palladium thin films for plasmonic hydrogen gas sensing

In this study, I prepared BK7 glass slides coated by a palladium (Pd) layer by the PVD technique. These samples were employed as plasmon active structures in classic Kretschmann-based SPR set-up. The application of H2 sensing structures based on palladium plasmonic active thin films were tested and investigated. Hydrogen sensing properties of Pd films were investigated at room temperature. The reflectances of p-polarized light from Pd thin films as a function of angle of incidence and wavelength were measured in synthetic air (or nitrogen) and in gas mixtures including hydrogen. Variations of the reflectance in the presence of hydrogen gas at room temperature revealed that the samples can sense hydrogen in a wide range of concentrations (0–2% vol/vol) without saturation behavior. The dynamic properties with various concentrations of H2 at low temperature and dry gas mixtures were investigated and the effects of these factors on hydrogen sensing properties were analyzed.