Modification of graphene based on a Ba2Cu8Ni2Se12 catalyst with CoS nanospheres for a counter electrode for dye-sensitized solar cells

A novel graphene-Ba2Cu8Ni2Se12 catalyst with CoS nanospheres (GBC) was synthesized via a facile hydrothermal method for use as a counter electrode (CE) in dye-sensitized solar cells (DSSCs). In this work, Ba2Cu8Ni2Se12 (BCNS) and CoS nanospheres were directly grown on graphene sheets showing strong interactions. The morphology and electrochemical and photovoltaic performances of GBC were studied. The GBC CE in bifacial DSSCs showed higher power conversion efficiency (12.37%), which is comparable to that of a traditional Pt electrode (4.07%). This result shown that the synergistic effects of the GBC structure provides a large catalytic active area and an excellent electron transfer pathway. The GBC CE exhibits good device performance and can serve as a low-cost CE as compared to Pt in the DSSCs.