Gas adsorption and gas-sensing properties of europium bisphthalocyanine derivative Langmuir-Blodgett thin films

Article abstract of DOI:10.1016/S1386-1425(97)00149-2

In this paper, europium bisphthalocyanine derivative (EuPc′₂) LB films transferred to an interdigital electrode have been prepared at room temperature. The dynamic response of the electrical conductance to Cl₂ gas is presented. At room temperature, the response time of 10-layer LB films of EuPc′₂ is 45 s and the recovery time is 1 min after exposure to a concentration of 50 ppm Cl₂. The reproducibility of the conductivity changes can be improved by using pulsed operation to reduce the exposure time to Cl₂. The change in film conductivity upon exposure of different concentrations of Cl₂ gas has been measured. The lowest detectable concentration of Cl₂ gas is 2 ppm. The maximum conductance change varies linearly with film thickness. The response time constants also increase with film thickness. The interaction between EuPc′₂ and Cl₂ in the LB films was monitored by UV-vis spectroscopy. LB films exposed to Cl₂ gave a red-shifted Q-band which can be predicted from the conductance data.