Facile, room-temperature synthesis of NiSe2 nanoparticles and its improved performance with graphene in dye-sensitized solar cells

•Through a facile, room-temperature process to prepare NiSe2 nanoparticles.•NiSe2 nanoparticles exhibited good PCE as CEs for Pt-free DSSCs.•Grapheme as a dopant could promote the electrocatalytic activity of DSSCs.•NiSe2 + 6 wt% graphene CE exhibited better PCE compared with Pt CE.

Metal selenides have been proposed as counter electrodes (CEs) to substitute for Pt in dye-sensitized solar cells (DSSCs) due to their good catalytic activity for the reduction of triiodide. In this paper, NiSe2 nanoparticles were synthesized by a facile, room-temperature process and used as the CEs. In order to further enhance the photovoltaic property, graphene was introduced by facile physical mixing. Eventually, with the assistance of graphene, NiSe2 + 6 wt% graphene CE exhibited better power conversion efficiency (PCE) compared with Pt CE.