Variation in the Optical Sensing Responses toward Vapors of a Porphyrin/Phthalocyanine Hybrid Thin Film

Spin-coated layers of zinc(II) tetra-4-(2,4-di-tertamylphenoxy)phthalocyanine (ZnPctamyl) and copper(II) tetrakis(p-tert-butylphenyl)porphyrin (CuPtphen) have been synthesized and used as solid state chemically interacting materials deposited in thin film form for the detection of alcohols, amines, ketones, alkanes, and pyridines for applications in food quality control. The UV-Vis variations obtained by the exposure of the sensing layers to the mentioned analytes in controlled atmosphere have been analyzed and compared with those deriving by a single thin film obtained by mixing the two metal complexes in an appropriate ratio. A multichannel monitoring of the main bands of the sensing layer due to the interaction with the analyte vapors became the basis to construct a set of independent sensors located on a single sensing element. The effects in the variation of the absorption bands of the blend system are compared with the variations in absorbance observed with the two sensing layers fabricated separately with each single compound. The interaction between some volatile organic compound species and the heterogeneous sensing layer shows a different behavior in the responses with respect to the results obtained with each single compound.