Oriented single-crystalline nickel sulfide nanorod arrays: two-in-one counter electrodes for dye-sensitized solar cells

An oriented millerite nickel sulfide (NiS) nanorod array was successfully grown on bare glass substrate. Metallic conductivity and outstanding electrocatalytic activity make it possible to function as a new type of two-in-one counter electrode (CE) in dye-sensitized solar cells (DSCs) to replace both the transparent conductive oxide (TCO) and Pt electrocatalyst. When applied in DSCs, an impressive power conversion efficiency of 7.41% was achieved, comparable to that of TCO supported Pt CE (7.55%). The NiS nanoarray film could be a potential candidate to realize a two-in-one CE in DSCs, which is highly desirable to reduce the fabrication cost of DSCs while retaining a comparable conversion efficiency.