Pyridine-carboxylates as new anchoring groups for organic sensitizers in DSSCs

In recent years, metal-free organic sensitizers for dye-sensitized solar cells (DSSC) have been shown to have reached an interesting level of efficiency, while not having all the problems associated with the presence of a metal. Often DSSCs have a "donor-?-acceptor" (D-?-A) architecture, where the acceptor groups is also involved in the interaction with titanium oxide1. In most of metal-free organic sensitizers, the acceptor/anchor group is a cyanoacrylate moiety but recently acceptors with different structural features, such as pyridine carboxylate, have been reported2. In this work, different dyes with a pyridine portion as acceptor group were synthesized and characterized, varying the position of the carboxyl group and the group D-? in the pyridine moiety. The isomers prepared showed significant differences both in absorption/emission spectra and in TiO2 up taking. The results was compared with analogues dye with cyanocrilate mojety as anchoring group. Moreover we have been showed as inserting a appropriate substituent on the pyridine ring is possible to adjust the optical properties of the dyes.