The variation of the electrical conductivity of ytterbium bisphthalocyanine 25-layer Langmuir–Blodgett (LB) films with temperature, time and in the presence of air, N2 and 5 ppm Cl2 in N2, has been investigated and compared with the variation of optical absorbance in the visible region under the same conditions. An activation energy of 0.31 eV has been measured for the carriers. A 200% increase in conductivity has been observed on the addition of 5 ppm Cl2 to a nitrogen atmosphere at a sample temperature of 120 °C. A pyrovoltage has also been measured with an activation energy of 3.0 eV associated with reordering of molecules within the layers.
