Chemically deposited polypyrrole-nanoparticle counter electrode for inorganic I−/I3− and organic T−/T2 dye-sensitized solar cells

Pure polypyrrole (PPy) and composited PPy-nanoparticles (multiwall carbon nanotubes (MWCNTs), nickel (Ni) or, titanium dioxide (TiO2)) films were coated on conductive glass by a chemical deposition method. They were used as dye-sensitized solar cell counter electrodes. The performance of pure PPy based dye-sensitized solar cells (DSSCs) was ∼6.00% and ∼2.81% for I−/I3− and T−/T2 electrolytes, respectively. The efficiencies increased after MWCNTs and Ni nanoparticle incorporation for both electrolytes, but decreased with TiO2 addition. PPy-MWCNTs DSSCs delivered the highest efficiency; ∼7.20% and ∼3.19% for I−/I3− and T−/T2 electrolytes, respectively. The improvement of the energy conversion efficiency after MWCNTs and Ni incorporation is attributed to an increase in the electrode surface area and/or a reduction of charge-transfer resistance at the electrolyte/counter electrode interface.