Polypyrrole and Polypyrrole-Multi Wall Carbon Nanotube for Alternative Counter Electrodes in Dye-sensitized Solar Cells

Abstract

In our present study, the composite film of PPy/MWCNT (polypyrrole and multi-wall carbon nanotubes) and PPy were proposed as counter electrodes (CEs) in dye-sensitized solar cells (DSSCs) to replace the precious Pt CE. The PPy and PPy/MWCNT composite films were fabricated on fluorine-doped tin oxide substrates by using a facile electrochemical polymerization route, and served as CEs in DSSCs. The electrochemical impedance spectroscopy and Tafel measurements revealed that the PPy/MWCNT CE possessed more excellent electrocatalytic activity and lower charge transfer resistance of 171.06 Ω in comparison with a PPy CE (338.6 Ω). The DSSC assembled with the PPy/MWCNT CE exhibited a better power conversion efficiency (PCE) of 4.17% under the illumination of 100 mW cm2, comparable to that of the DSSC based on reference Pt CE (6.86%). Compared with a DSSC using PPy CE with PCE of 3.45%, the PCE of DSSC using PPy/MWCNT CE was increased by 20%. Therefore, the PPy/MWCNT composite film can be considered as a promising alternative CE for DSSC due to its high electrocatalytic performance and excellent electrochemical stability.