Pt-sputtering-like NiCo2S4 counter electrode for efficient dye-sensitized solar cells

Abstract

A facile method is developed to prepare NiCo2S4 counter electrode (CE) which is in-situ grown on SnO2: F transparent conductive glass (FTO) with mirror-like smooth surface. As demonstrated by analyses, the electrocatalytic activity, electrical conductivity and light reflectivity of the NiCo2S4 CE exceed or approach to those of Pt-sputtering CE, and are much better than those of Pt-pyrolysis CE. Thus the conversion efficiency (η) of the dye sensitized solar cell (DSSC, 8.10%) based on NiCo2S4 CE is higher than the cell based on Pt-sputtering CE (7.60%), and is superior to the one based on Pt-pyrolysis CE (7.01%). Remarkably, NiCo2S4 CE also exhibits excellent chemical and mechanical stability. There are almost no changes on morphology and interfacial adhesion between NiCo2S4 film and FTO substrate after sequential 1000-time scans of cyclic voltammetry and 100 cycles of 3M Scotch tape detachment. The η of DSSC drops a little from 8.10% to 7.94%. The numerous superiorities of the Pt-sputtering-like NiCo2S4 CE permit its promising application in DSSCs.