EFFECT OF NITROGEN-DIOXIDE ON TITANIUM BISPHTHALOCYANINATO THIN-FILMS

Thin films of Titanium bis-phthalocyaninato (TiPc2) are deposited on i nterdigital electrodes by evaporation under vacuum and have been inves tigated as semiconducting gas sensors. Oxidation of the films by NO2 i s studied by visible absorption spectroscopy and IR spectroscopy of ne utral and oxidised films. The variation at room temperature (RT) of el ectrical conductivity with different concentrations of NO2 has been in vestigated. The results describe the existence of a conductivity maxim um during the oxidation. The analysis of the optical spectra of TiPc2 during NO2 adsorption and desorption gives the possibility to explain the change of the conductivity in terms of concentration of species pr esent in the reaction. (C) 1998 Elsevier Science S.A. All rights reser ved.