On the characterisation and gas sensing properties of Cu(II) tetra(alkylamino carbonyl) phthalocyanine LB films

Langmuir-Blodgett (LB) films of a substituted phthalocyanine containing the amidic group (CONH) instead of the ester group (COO) have been studied. Floating films were spread onto the water surface from chloroform solutions and were transferred onto hydrophilic quartz substrates using the vertical lifting method. Linearly polarised light absorbance measurements were performed at room temperature in the 400-800 nm spectral range. The average orientation of the phthalocyanine molecular rings in the LB film, with respect to the normal to the substrate and dipping direction, has been evaluated. Dynamic response characteristics of the electrical conductance of the LB films to different NO2 concentrations, carried out in dry air and at room temperature, have shown a high sensitivity to concentrations of nitrogen dioxide smaller than 50 ppm. (C) 1998 Elsevier Science S.A. All rights reserved.