Metal containing polymers with wide absorption range for photovoltaic applications

Abstract

We report the synthesis of a series of conjugated polymers that contain transition metal complexes at the pendant chain. The complexes are based on ruthenium or rhenium metal center coordinated with different aromatic diimine ligands. Optical absorptions by the metal complexes and conjugated main chain cover most of the visible region, resulting in a wide photosensitization range. Energy transfer from the conjugated main chain to metal complex in some polymers was also observed. The polymers were fabricated into single layer photovoltaic devices. The roles of the metal complexes in the photosensitization process were studied by measuring the external quantum efficiency at different wavelength. It was found that both the pi-conjugated system and metal complex participated in the sensitization process. From time-of-flight experiment, the hole and electron carrier mobilities of the polymers were found to be in the order of 10e-4 cm2/Vs.