Development of reduced graphene oxide/carbon black nanocomposites as counter electrodes and porphyrin anodes for dye-sensitized solar cells

The continued reliance on fossil fuels has adversely affected the terrestrial atmosphere, necessitating the development of sustainable energy technologies. In this study, RGO/ACB/Zn and RGO/ACB/Zn/Cu nanocomposites (RGO = reduced graphene oxide, ACB = acetylene carbon black) were developed, characterized, and evaluated as low-cost counter electrodes (CEs) for dye-sensitized solar cells (DSSCs). Four porphyrin-based dyes, including free-base and copper(II) derivatives, were employed as photoanode sensitizers. The photovoltaic performance of the fabricated DSSCs was systematically investigated. Among the tested devices, the DSSC incorporating the RGO/ACB/Zn/Cu CE and the copper(II) 4-(10,15,20-tris(4-methoxyphenyl) porphyrin) benzoic acid (compound 3) exhibited the highest power conversion efficiency (PCE) of 2.11%, which is attributed to improved charge transfer and enhanced catalytic activity at the CE/electrolyte interface, as confirmed by electrochemical impedance spectroscopy (EIS) and Tafel polarization measurements. These findings demonstrate the potential of RGO-based nanocomposites as efficient alternatives to noble-metal counter electrodes in DSSCs.