Influence of electropolymerized polypyrrole optical properties on bifacial Dye-Sensitized Solar Cells

In this work the effect of different doping anions on transparency, photovoltaic efficiency and interface properties of electropolymerized polypyrrole (PPy) films as counter electrode in bifacial DSSCs was study. The transparency of the counter electrode becomes relevant in order to enhance the final device efficiency and for alternative application area like of Building-Integrated Photovoltaic. PPy was prepared by electrochemical process with doping anions: chloride, perchlorate, sulfate and dodecylbenzenesulfonate. PPy doped with high concentration (0.5 M) of small anions (chloride) produced the highest transparency film (65% at 525 nm), the DSSCs with highest efficiency ratio (close to 70%) and lowest device reflectance (11%). Considering all of these results, not only the transparency of counter electrode was found to influence the efficiency of the bifacial DSSCs, but also the optical properties of PPy/electrolyte interface. This interface is probably strictly affected to the PPy morphology produced by different doping anions and the electropolymerization process used. (C) 2017 Elsevier Ltd. All rights reserved.