Facile fabrication of polypyrrole/functionalized multiwalled carbon nanotubes composite as counter electrodes in low-cost dye-sensitized solar cells

This paper reports facile fabrication of polypyrrole (Ppy)/functionalized multiwalled carbon nanotube (f-MWCNT) nanocomposite films on rigid fluorine-doped tin oxide (FTO) and flexible ITO-coated polyethylene naphthalate (PEN) substrates by a drop casting method, and their application as counter electrodes in dye-sensitized solar cells (DSSCs). The electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) measurements of this solution processed Ppy/f-MWCNT nanocomposite film display good catalytic performance for I3−/I− solution. The photoelectric conversion efficiency of the DSSCs with the Ppy/f-MWCNT counter electrodes on FTO and PEN substrates reaches 7.02% and 4.04%, respectively, under AM1.5 illumination of 100 mW cm−2, comparable to that of the DSSCs based on sputtered Pt electrodes. The fabrication method of such counter electrodes is simple under room temperature and can be applicable in large-scale production.