PHOTOCONDUCTIVITY OF COPOLYIMIDE FILMS CONTAINING TETRAPHENYLPORPHYRIN AND CARBAZOLE MOIETIES

A series of polyimide copolymers based, on pyromellitic dianhydride, 3 ,6-diaminocarbazole, and terta(4-aminophenyl)porphyrin were synthesize d. The ''precursors'', copolyamic acids, and the copolyimides were cha racterized by IR, UV-visible, and emission spectra and thermogravimetr y. The mole ratios of tetraphenylporphyrin (TPP) to carbazole (Cz)in t he polymers calculated from the UV-visible spectra indicate that TPP a nd Ct were incorporated into the polymer backbones as expected. The co polyimide films were fabricated into bilayer photoreceptors as a charg e-generating layer to investigate their photoconductivity. It was foun d that the photosensitivity of the copolyimides increases with the inc orporation of TPP into the polymer chains. These results were compared with those of the tetraphenylporphyrin-doped pyromellitic/3,6-diamino carbazole polyimide film and explained on the basis of charge-transfer complex formation.