NO2 detection at room temperature with copper phthalocyanine thin film devices

In this work, we report the effect of post-deposition film treatment on the NO2 sensing properties of CuPc thin films for room temperature operation. The gas-sensitive response of the electrical conductivity to doping with NO 2, doping with oxygen (in air) and cooling to 77 K in liquid nitrogen are r eported. The pretreatment with NO, is shown to improve the gas sensing prop erties by providing both an increase in the magnitude of the conductivity c hange for a given NO2 concentration and a significant improvement in the re covery time. Data is analysed using an Elovich model, which suggests that t he cooled devices have the best fit to this model; the data for the NO2 dop ed devices suggest a Langmuir behaviour. For all devices, a simple time der ivative of the change in current provides a measure: of concentration fur r eal time gas sensing applications. (C) 2000 Elsevier Science S.A. All right s reserved.