The role of the dye in the DSC consists in absorbing the solar radiation and to pump electrons into the semiconductor. The dye is regenerated by accepting an electron from the redox couple. In order to increase the efficiency of the cell, dyes must present some spefic characteristics:

- Strong absorption of the solar spectrum on the visible and near-IR.
- Effective binding to the semiconductor.
- Excited State Oxidation Potential energy higher (more positive) than the semiconductore CB edge to efficiently inject photoexcited electrons.
- Ground State Oxidation Potential lower  (more negative) than the that of the redox mediator for a fast regeneration step.
- Rapid electron injection with respect to the decay times of the excited state.


Up to now, the renowned N3 and N719 Ru(II)-polypyridyl photosensitizers, have shown the highest performances, with solar energy-to-electricity conversion efficiencies exceeding 11%. To achieve higher efficiencies, new dyes and a deeper understanding of the interaction between the dye and the TiO2 nanoparticle are essential. There is a tremendous impetus in the design of new and more efficient sensitizers and to this end, we have employed molecular engineering together with advanced quantum chemical calculations.

Fully organic sensitizers have been only recently received attention for application in DSC. Due to the lack of systematic computational investigations on organic dyes, we have carefully investigated many aspects concerning their photophysical properties highlighting some problems with “conventional” theoretical approaches that need to be properly addressed for a thorough understanding of this extremely important class of dye-sensitizer.



Nazeeruddin, M. K.; De Angelis, F.;  Fantacci, S.;  Selloni, A.;  Viscardi, G.;  Liska, P.;  Ito, S.; Bessho,  T.; Graetzel, M.  J. Am.Chem. Soc. 2005, 127, 16835-16847.

De Angelis, F.; Fantacci, S.;  Selloni, A. Nanotech., 2008, 424002

Pastore, M.; Fantacci, S.; De Angelis, F. J. Phys. Chem. C 2010, 114, 22742-22750.

Pastore, M.; Mosconi, E.; De Angelis, F.; Graetzel, M. J. Phys. Chem. C 2010, 114, 7205-7212.