Oleic acid-mediated synthesis of small-sized and monodisperse NiSe2 nanowires as counter electrode catalysts for triiodide reduction

Abstract

Developing a low-cost counter electrode (CE) catalyst with outstanding catalytic activity for the triiodide (I3−) reduction reaction (IRR) in dye-sensitized solar cells (DSSCs) is highly desirable. Herein, small-sized NiSe2 nanowires (NiSe2-W) were controllable synthesized by introducing the oleic acid (OA) as organic capping ligand into reaction system. Similarly, the monodisperse NiSe2 nanoparticles (NiSe2-P) with the small-sized were prepared by the same synthesis strategy under the absence of OA. The difference in morphologies between NiSe2-W and NiSe2-P can be attributed to the anisotropy and the oriented attachment of OA, and then the possible growth mechanism of them had been proposed. On the basis of the unique 1D nanostructure and chemical composition merits, power conversion efficiency (PCE) of 8.78 % was achieved when the NiSe2-W exploited as the CE catalyst for DSSCs, superior to that of the state-of-the-art Pt-based DSSCs (7.97 %) in parallel. Moreover, the relevant electrochemical measurements revealed that the as-prepared NiSe2-W displayed superior catalytic activity for IRR and good electrochemical durability in the redox electrolyte containing the I3−/I−. Then the NiSe2-W with unqiue 1D structure had been expected to replace Pt for the application of DSSCs, and could be a potential candidate in extensive new energy applications.