Improvement of the photovoltaic performance of solid-state dye-sensitized device by silver complexation of the sensitizer cis-bis(4,4′-dicarboxy-2,2′bipyridine)-bis(isothiocyanato) ruthenium(II)

The photovoltaic performance of solid-state dye-sensitized solar cells based on 2,2′7,7′-tetrakis(N,N-di-p-methoxyphenyl-amine)-9,9′-spiro-bifluorene has been improved to 3.2% overall conversion efficiency under air mass (AM) 1.5 illumination by performing the dye adsorption in the presence of silver ions in the dye solution. The enhancement in overall device efficiency is a result of increased open circuit potential and short circuit current. Different spectroscopic methods, such as x-ray photoelectron, Fourier-transform infrared and UV-visible spectroscopy have been employed to scrutinize the impact of the silver on the dye-sensitized device. From spectroscopic evidence it is inferred that the silver is mainly binding to the sensitizer via the amphidentate thiocyanate, allowing the formation of ligand-bridged dye complexes.