title: Influence of electrolyte co-additives on the performance of dye-sensitized solar cells.
abstract: The presence of specific chemical additives in the redox electrolyte results in an efficient increase of the photovoltaic performance of dye-sensitized solar cells (DSCs). The most effective additives are 4-tert-butylpyridine (TBP), N-methylbenzimidazole (NMBI) and guanidinium thiocyanate (GuNCS) that are adsorbed onto the photoelectrode/electrolyte interface, thus shifting the semiconductor's conduction band edge and preventing recombination with triiodides. In a comparative work, we investigated in detail the action of TBP and NMBI additives in ionic liquid-based redox electrolytes with varying iodine concentrations, in order to extract the optimum additive/I2 ratio for each system. Different optimum additive/I2 ratios were determined for TBP and NMBI, despite the fact that both generally work in a similar way. Further addition of GuNCS in the optimized electrolytic media causes significant synergistic effects, the action of GuNCS being strongly influenced by the nature of the corresponding co-additive. Under the best operation conditions, power conversion efficiencies as high as 8% were obtained.
authors.affiliation: Institute of Physical Chemistry, NCSR "Demokritos", Aghia Paraskevi Attikis, Athens 15310, Greece. stergt@chem.demokritos.gr.
authors.forename: Thomas
authors.initials: T
authors.lastname: Stergiopoulos
authors.forename: Evangelia
authors.initials: E
authors.lastname: Rozi
authors.forename: Chaido-Stefania
authors.initials: CS
authors.lastname: Karagianni
authors.forename: Polycarpos
authors.initials: P
authors.lastname: Falaras