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A novel organic compound was designed and successfully synthesized for the fabrication of QCM based sensors to detect the low concentrations of BTX gases in indoor air. The effect of the long-range electron orbital delocalization on the BTX vapour sensing properties of azo-bridged Pcs based chemiresistor-type sensors have also been investigated in this work. The sensing behaviour of the film for the online detection of volatile organic solvent vapors was investigated by utilizing an AT-cut quartz crystal resonator. It was observed that the adsorption of the target molecules on the coating surface cause a reversible negative frequency shift of the resonator. Thus, a variety of solvent vapors can be detected by using the phthalocyanine film as sensitive coating, with sensitivity in the ppm range and response times in the order of several seconds depending on the molecular structure of the organic solvent. [ABSTRACT FROM AUTHOR]

The effects of dipole moment of the analyte molecules on the response characteristics of bis(pentafluorophenyl)methoxyl substituted phthalocyanine thin film are explored to understand the details of molecular interactions of analytes with the sensor surface which lead to charge depletion and the chemiresistive effect. The concentration dependence of dc conductivity is measured to investigate the adress the response of the Pc film. It was found that the speed of the response is dominated by the polarity of the analytes. Four kinetic models, the first-order equation, the Elovich model, the second-order equation and the Ritchie's equation were selected to follow the adsorption process. The rate constants, equilibrium capacities and related correlation coefficients for each kinetic model were calculated and discussed. The second-order equation was the best of the various kinetic models studied to describe the adsorption kinetic of VOC vapours on Pc film, as evidenced by the highest correlation coefficients. [ABSTRACT FROM AUTHOR]