An efficient bilayer graphene-conducting polymer counter electrode for dye sensitized solar cells

Abstract

A counter electrode was fabricated for dye sensitized solar cells (DSSCs) by the layer-by-layer approach that included reduced graphene oxide (rGO) and poly (3,4-ethylene dioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS). This design aimed to substitute the conventionally used high-cost, scarce, and complex method to produce platinum (Pt) counter electrode. This bilayer structure was developed by simple doctor blade and spin coating methods. The electrochemical performance of rGO/PEDOT:PSS counter electrode characterised by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and Tafel polarisation studies showed significant results in electrochemical stability and catalytic activity comparable to Pt counter electrode. Photovoltaic analysis of the DSSC assembled with rGO/PEDOT:PSS counter electrode revealed a V_oc, J_sc, and FF of 0.66 V, 25.3 mA/cm², and 56.9%, respectively. An overall efficiency of 9.5% was obtained with the rGO/PEDOT:PSS counter electrode, which was slightly less than that of Pt counter electrode (9.8%). The results demonstrated that this counter electrode can achieve comparable performance to Pt, which makes it a suitable alternative for easily manufacturable, cost-effective and high-performance DSSCs.