@ARTICLE{Jakubik_W.P._Surface_2008, author={Jakubik, W.P. and Urbańczyk, M. and Maciak, E. and Pustelny, T.}, volume={vol. 56}, number={No 2}, journal={Bulletin of the Polish Academy of Sciences Technical Sciences}, pages={133-138}, howpublished={online}, year={2008}, abstract={A layered sensor structure of metal-free phthalocyanine H2Pc (~160 nm) with a very thin film of palladium (Pd ~20 nm) on the top, has been studied for hydrogen gas-sensing application at relatively low temperatures of about 30°C and about 40°C. The layered structure was obtained by vacuum deposition (first the phthalocyanine Pc and than the Pd film) onto a LiNbO3Y- cut Z-propagating substrate, making use of the Surface Acoustic Wave method, and additionally (in this same technological processes) onto a glass substrate with a planar microelectrode array for simultaneous monitoring of the planar resistance of the layered structure. In such a layered structure we can detect hydrogen in a medium concentration range (from 0.5 to 3% in air) even at about 30°C. At elevated temperature up to about 40°C the differential frequency increases proportionally (almost linearly) to the hydrogen concentration and the response reaches its steady state very quickly. The response times are about 18 s at the lowest 0.5% hydrogen concentration to about 42 s at 4% (defined as reaching 100% of the steady state). In the case of the investigated layered structure a very good correlation has been observed between the two utilized methods - the frequency changes in the SAW method correlate quite well with the decreases of the layered structure resistance.}, type={Artykuły / Articles}, title={Surface acoustic wave hydrogen gas sensor based on layered structure of palladium/metal-free phthalocyanine}, URL={http://www.czasopisma.pan.pl/Content/110745/PDF/(56-2)133.pdf}, keywords={layered structure, metal-free phthalocyanine, palladium, hydrogen gas sensor, surface acoustic wave}, }