dye and cobalt electrolyte interaction effect on the performance of dye-sensitized solar cell

The effects of changing ligand structures of cobalt complexes as electrolytes on the performance of the dye-sensitized solar cell were investigated. in this paper, cobalt(ii/iii) tris(2,2′-bipyridine), cobalt(ii/iii) tris(4,4′-dimethyl-2,2′-bipyridine) and cobalt(ii/iii) tris(4,4´- dimethoxy-2,2′-bipyridine) complexes as electrolytes in conjugate with organic dye d149 were investigated to consider the correlation of the cobalt complexes structural on the efficiency of the dye-sensitized solar cell. the voc values of the prepared cells are related to the redox potential of their complexes and the maximum voc was observed with cobalt(ii/iii) tris(2,2′-bipyridine) electrolyte. the obtained results represented that the cobalt(ii/iii) tris(4,4´-dimethyl- 2,2′-bipyridine) electrolyte has the highest efficiency in the solar cell compared with other cobalt complexes. these observed results have been interpreted by a possible interaction between the dye and cobalt complexes, which is more pronounced in the cobalt(ii/iii) tris(4,4´-dimethoxy-2,2′-bipyridine) cell. this interaction should be fine-tuning with the structure of dye and complex to increase the efficiency of the dye-sensitized solar cell. in addition, the results demonstrated that a thinner layer of the tio2 film decrease both the effects of mass transport issues and the charge recombination, therefore, it has significant advantages for cobalt electrolyte.