Electrochemical Properties of Electrodeposited PEDOT Counter Electrode for Dye-sensitized Solar Cells

Poly(3,4-ethylenedioxythiophene) (PEDOT) films were coated on fluorine-doped tin oxide (FTO) conductive glass by electrodeposition and applied as the counter electrode (CE) in dye-sensitized solar cells (DSSCs). Scanning electron microscopy (SEM) revealed the nanofiber-like structure of the PEDOT films. The maximum energy conversion efficiency obtained from the 0.5-mu m-thick PEDOT CE was 5.1%, which was almost equivalent to that of the standard Pt CE (5.2%). From electrochemical impedance spectroscopy (EIS) results, the large charge transfer resistance of direct current solar cells was attributed to the formation of unbounded PEDOT chains that minimized the I-3(-) reduction rate.