FABRICATION OF LANGMUIR-BLODGETT-FILMS OF POLY(3-HEXYLTHIOPHENE) AND METAL-SUBSTITUTED PHTHALOCYANINES

Langmuir-Blodgett monolayer and multilayer films were formed from nickel tetra-tert-butylphthalocyanine, iron tetra-tert-butylphthalocyanine, and mixtures of these phthalocyanines with poly(3-hexylthiophene). In the mixed films, the phthalocyanine molecules serve as both a surface-active agent to promote spreading and an electroactive material. The structures of the resultant LB films were investigated by using optical absorption spectroscopy, FTIR spectroscopy, and low-angle X-ray diffraction. In the mixed LB films, the nickel phthalocyanine molecules were found to stack in one-dimensional arrays with their rings oriented essentially perpendicular to the substrate surface. The mixed iron phthalocyanine LB films, on the other hand, were comprised of both one-dimensional arrays and randomly oriented rings due to a stronger intermolecular interaction developed between the poly(3-hexylthiophene) and iron phthalocyanine molecules. In both cases, the PHT-conjugated chains were found to be oriented nearly parallel to the substrate. The multilayer films of these systems were rendered electrically conductive by doping with I2 or SbCl5. Conductivities in the range of 10(-1)-10(-6) S cm-1 were observed in the doped films.