Electrochemically Prepared Poly(3,4‐ethylenedioxy‐ thiophene)/Polypyrrole Films with Hollow Micro‐/Nanohorn Arrays as High‐Efficiency Counter Electrodes for Dye‐Sensitized Solar Cells

Abstract

A two‐step approach is employed for quick and controllable electropolymerization of poly(3,4‐ethylenedioxythiophene) (PEDOT)/polypyrrole (PPy) hollow micro‐/nanohorns on fluorinated tin oxide (FTO) glass substrates as counter electrodes (CEs) for Pt‐free dye‐sensitized solar cells (DSCs). PPy films with hollow micro‐/nanohorn arrays are grown on FTO glasses by a modified pulse potentiostatic method in the first step. Then PEDOT is potentiostatically polymerized onto them as the CEs. Owing to the relatively high catalytic activity of PEDOT and the high specific surface area of hollow micro‐/nanohorn PPy (hPPy), the compound film shows electrocatalytic activity for I3− reduction similar to that of Pt. Therefore, DSCs assembled with this CE exhibit comparable power conversion efficiency (7.08 %) to DSCs with Pt CEs (6.88 %). The PEDOT/PPy film with hollow micro‐/nanohorn arrays can be considered to be a promising alternative CE material for Pt‐free DSCs.