Gas-sensing properties of metallo-phthalocyanine thin films as a function of their crystalline structure

Abstract PcM (M = Cu, Fe, Pb, Li) thin films are studied as sensitive elements of semiconducting gas sensors. After exposure to oxidizing gases (NO 2 , O 2 , Cl 2 , I 2 ), the electrical conductivities of the materials go through a maximum at temperature T m , which corresponds to the maximum sensitivity to the gas and thus to the temperature of operation as gas sensors. We describe the evolution of T m with the morphology of the film and with the heat and gaseous treatments, and its consequences with regard to the gas-sensing application.