An in situ polymerized PEDOT/Fe3O4 composite as a Pt-free counter electrode for highly efficient dye sensitized solar cells

Abstract

3,4-Ethylenedioxy thiophene (EDOT) precursor solution doped by Fe₃O₄ was spin-casted onto fluorine doped tin oxide (FTO) glass and formed poly(3,4-ethylenedioxy thiophene) (PEDOT)/Fe₃O₄ hybrid films by an in situ polyreaction. The films were utilized as the counter electrode in dye sensitized solar cells (DSSCs). Photoelectric conversion efficiency (PCE) for DSSCs based on PEDOT/Fe₃O₄ varied with the content of Fe₃O₄ in the precursor solution. When the content of Fe₃O₄ was 2 mg ml⁻¹ in the precursor solution (PEDOT/Fe₃O₄-2), the best performance (8.69%) was obtained. In comparison, that of a DSSC with a Pt counter electrode is 8.35%. According to the surface microtopography and electrochemical analysis, large active areas, consecutive electronic transmission channels and lower charge transfer resistance could be responsible for the high PCE.