K. Nakamura, S. Ishii and Y. Yoshida*

Faculty of Engineering, Toyo University
Kawagoe, Saitama 350-8585, Japan
yoshida@eng.toyo.ac.jp

Copper phthalocyanin is well-known as blue organic pigment or organic electronic material to be applied in the various field such as chemical industry, electronics, or medical field, etc. Metal porphyrin has the similar chemical structure and functionalities to metal phthalocyanin to be expected as the organic electronic material having higher functionalities than phthalocyanin compounds. Recently, thin films of various organic pigment has been noted in electronics field. In this paper, plasma polymerization of metal porphyrin complex (cobalt tetraphenylporphyrin; CoTPP) was investigated, and the chemical structure and electronic properties of CoTPP plasma-polymerized thin films were reported.

From the results of XPS spectra of CoTPP plasma-polymerized thin films, element ratios on surface of thin films, N/C, metal/C ratio, were found to decrease with increasing RF power. The composition ratios of CoTPP plasma polymerized thin film prepared by lower RF power were similar to that of CoTPP monomer, but N/C or metal/C of CoTPP films obtained by higher RF power decreased. O/C composition ratios of all plasma polymerized thin films increased as compared with that of vapor deposition thin film. It considered that residual radical activating species in plasma polymerized thin film reacted with oxygen or steam in air to form hydroxyl group or carboxyl group.

A sandwich type device of Au/plasma polymerized thin film/ ITO glass was prepared. Plasma polymerized CoTPP thin film at 10 RF power showed the property of semi-conductor.