Comparative NH₃-sensing properties in tetra-iso-pentyloxymetalophthalocyanine spin-coating films

Spin-coating films of copper, nickel and lead 2,9,16,23-Tetra-iso-pentyloxyphthalocyanine (Cu, Ni and PbPc-4) were obtained and characterized by ultra violet visible absorption spectra and atomic force microscopy. The gas sensing behaviors of the films were investigated with respect to NH₃ at room temperature. In addition, the effects of film morphology, center metal and substitution group position on gas sensing properties were also discussed. It was found that the MPc-4 films exhibited better response, reversibility, selectivity and faster response and recovery characteristic than 1,8,15,22-Tetra-iso-pentyloxymetalophthalocyanine (MPc-3). In detail, the response value was in the following order: CuPc-4, NiPc-4, PbPc-4 and MPc-3, the response and recovery time were in the following order: PbPc-4, CuPc-4, NiPc-4 and MPc-3.