Langmuir−Blodgett Multilayers Based on Copper Phthalocyanine as Gas Sensor Materials:  Active Layer−Gas Interaction Model and Conductivity Modulation

Abstract

Langmuir−Blodgett films of copper(II) [tetrakis((3,3-dimethylbutoxy)carbonyl)]phthalocyanine and copper(II) [tetrakis( n -butoxycarbonyl)]phthalocyanine have been studied as sensitive elements of gas sensors. Moreover, alternate LB films of the two compounds and LB films obtained from a 1:1 mixture of them have also been investigated. In particular, after exposure to NO 2 oxidizing gas, the electrical conductivity of the materials goes through a maximum at a temperature of about 170 °C corresponding to the maximum sensitivity to the gas. The sensitivity and stability of the response of the active layers to NO 2 are discussed as well as the application of these materials as the sensitive elements for gas-sensing devices.