Bilayer structures based on metal phthalocyanine and palladium layers for selective hydrogen detection

Abstract

In this work, bilayer structures in which a Pd layer was deposited on the surface of palladium phthalocyanine film (PdPc/Pd) by a Metal-Organic Chemical Vapor Deposition technique were studied as active layers of chemiresistive sensors for selective detection of hydrogen. Surface morphology, microstructure and composition of Pd layers were investigated by scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. Three sets of bilayer structures with Pd layer thicknesses of 55–80 nm, 100–120 nm and 140–160 nm were obtained to examine the effect of the thickness on the electrical sensor response toward gaseous hydrogen (1–30 v.%). It has been shown that the bilayer structures with 55–80 nm thick Pd layers exhibit the maximal sensor response and can be effectively used for selective detection of hydrogen in the concentration range from 1 to 30% in the presence of gaseous ammonia, CO2, NO2, and chlorinated alkane vapours.