Photoconducting polymers containing covalently attached ruthenium complexes as a photosensitizer

Abstract

We have prepared photoconducting polymers that have ruthenium (Ru) complexes as photosensitizers. Ru complexes were introduced to utilize their high quantum yield and the long lifetime of the lowest energy metal–ligand charge transfer (MLCT) state for photo-charge generation. Ru(bpy)2(m-COOH-4-methylbpy)(PF6)2 was covalently attached to poly (N-vinylcarbazole) (PVK) using Friedel–Crafts acylation. Ru(bpy)2[m-(oxo-PVK)bpy](PF6)2 was prepared to have various weight percentages of Ru complexes. We have measured photo-charge generation efficiency and photoconductivity of PVK-Ru complexes with 632.8nm He–Ne laser and xenon lamp of the visible region. The wavelength dependence of photo-charge generation efficiency and photoconductivity was similar to their 3MLCT absorption spectra. It was expected that Ru complexes would extend the photosensitivity of polymers to the region of longer wavelengths through the presence of their lowest MLCT energy. The photo-charge generation efficiency and photoconductivity of these polymers was found to be greater than that of PVK: Ru-complex composites.