Nanoporous Reduced Graphene Oxide and Polymer Composites as Efficient Counter Electrodes in Dye-Sensitized Solar Cells

The introduction of an efficient and precious platinum (Pt) free counter electrode (CE) for dye-sensitized solar cells (DSSCs) is an important aspect to address. In this report, we have employed nanoporous reduced graphene oxide (PG) containing PEDOT:PSS–PG composite on FTO substrate as CEs, which have shown excellent diffusion of I₃^–, remarkable photocatalytic activity, and better device performance along with desired stability. The investigated cathode material has been prepared by mixing PGs and highly conducting PEDOT:PSS. Experimental measurements and analyses such as electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and so on indicate that PEDOT:PSS–PG is a promising cathode material for a Pt-free CE in DSSCs. EIS indicates that the PEDOT:PSS–PGs have lower interfacial charge-transfer resistance because of their high electrical conductivity and superior electrocatalytic activity. The achieved photoconversion efficiency (η) of a DSSC employing the Pt-free PEDOT:PSS–PG/FTO CE is 9.57%, which is found to be comparable to that of Pt/FTO CE based DSSC (9.64%) under a simulated solar light illumination of 100 mW/cm².