Proceedings of 6th International Conference on Hybrid and Organic Photovoltaics (HOPV14)
Publication date: 1st March 2014
Today Ru(II)-bipyridinic complexes are among the most efficient sensitizers for dye sensitized solar cells (DSSCs). Their main weak point is the presence of thiocyanate as ancillary ligand: it is a monodentate ligand that can be easier replaced by other competing ligands such as I- ion or 4-t-butylpyridine (often used to raise the conduction band of TiO2 as well as the photovoltage [1,2]), giving less efficient species. This issue has prompted innovative research on the synthesis of "thiocyanate-free" Ru(II) complexes.
The first example of a DSSC based on a simple pyridyl-tetrazolate ruthenium dye (the complex [Ru-(tetrazpy)(dcbpy)2]Cl where dcbpy is 2,2′-bipyridine-4,4′-dicarboxylic acid) was recently reported by some of us [3], with a conversion efficiency of 3%. This is a promising data considering the simplicity of the tetrazpy ligand.
As a further development, we synthetized and characterized new Ru(II) complexes with substituted and p-delocalized pyridyl-tetrazolate ligands with the aim of enhancing the intensity of the sensitizer's absorption; the pyridyl ring was also replaced by an isoquinoline.
[1]. Boschloo, G.; Haggman, L.; Hagfeldt, A. J. Phys. Chem. B 2006, 110, 13144-13150. [2]. Kusama, H.; Konishi, Y.; Sugihara, H.; Arakawa, H. Sol. Energy Mater. Sol. Cells 2003 80, 167-179. [3]. Dragonetti, C.; Colombo, A.; Magni, M.; Mussini, P.; Nisic, F.; Roberto, D.; Ugo, R.; Valore, A.; Valsecchi, A.; Salvatori, P.; Lobello, M. G.; De Angelis, F. Inorganic Chemistry 2013 52, 10723-10725.