Open Access Nano Express

Influence of electrolyte co-additives on the performance of dye-sensitized solar cells

Thomas Stergiopoulos1*, Evangelia Rozi1, Chaido-Stefania Karagianni2 and Polycarpos Falaras1*

Author Affiliations

1 Institute of Physical Chemistry, NCSR "Demokritos", Aghia Paraskevi Attikis, Athens 15310, Greece

2 School of Chemical Engineering, National Technical University of Athens, 9 Iroon Polytechniou St., 15780 Zografou, Athens, Greece

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Nanoscale Research Letters 2011, 6:307  doi:10.1186/1556-276X-6-307

Published: 7 April 2011

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.