Structure of Vacuum-deposited Tl₂Pc Film and its Optical and Electrical Properties

Dithallium phthalocyanine (Tl₂Pc) was synthesized by direct reaction of Tl metal with 1,2-dicyanobenzene. A thin film of the product was prepared by vacuum deposition on KCl single-crystalline substrate and its structure and epitaxy were examined by electron microscopy. The crystal structure of the thin film was the same as the orthorhombic structure reported previously. The film grew epitaxially on KCl substrate as expected from point-on-line coincidence. The UV-vis spectrum of the film was measured and compared with that of an as-synthesized powder sample. The UV-vis spectrum of the thin film of Tl₂Pc showed some differences from that of the powder in the visible region, which may result from the difference in molecular orientation. The electrical resistance of a Tl₂Pc thin film deposited on mica was about 10¹⁰Ω in our measuring set-up, which means that the film does not show high conductivity.