Graphene Nanoplatelets–Nickel Nanoparticles Hybrid Counter Electrodes for Low-Cost and Efficient Dye-Sensitized Solar Cells

Abstract

Reducing the cost of dye-sensitized solar cells (DSSCs) by replacing the expensive platinum (Pt) counter electrode (CE) with low-cost and earth-abundant materials without sacrificing their power conversion efficiency (PCE) is a topic of high interest. Herein, we prepared graphene nanoplatelets/nickel nanoparticles (GnPs/NiNPs) hybrid as a CE for DSSCs by electrochemical deposition of NiNPs onto fluorine-doped tin oxide (FTO) followed by spin coating of GnPs onto NiNPs/FTO electrodes. The optimal GnPs/NiNPs-CE with homogeneously distributed NiNPs with well-defined crystallinity exhibited excellent catalytic activity toward the I−/I3 − redox mediator with low charge transfer resistance at the electrode∣electrolyte interface. The DSSCs with an optimized GnPs/NiNPs-CE electrode exhibited a substantial improvement in efficiency to 7.24%, which is similar to the PCE of the cells with Pt-CE (ca. 7.99%). The GnPs/NiNPs-CE is a promising replacement for the expensive Pt used in DSSCs.