A multifunctional pentlandite counter electrode toward efficient and stable sensitized solar cells

Counter electrode at the cathode side of sensitized solar cells (SSCs) plays a critical key role in determining the device performance. Active and stable counter electrodes that can work over a wide range of electrolyte systems are highly desired for SSCs. Here, we report a mixed ternary pentlandite, Ni 3 Co 6 S 8 , as an efficient multifunctional counter electrode for SSCs with various redox mediators (I 3 − /I − , T 2 /T − , Co(bpy) 3 3+/2+ and S n 2− /S 2− ). Ni 3 Co 6 S 8 shows not only similar catalytic activity to Pt for I 3 − /I − redox shuttle but also superior catalytic activity for T 2 /T − , Co(bpy) 3 3+/2+ , and S n 2− /S 2− redox mediators. Furthermore, SSCs assembled with Ni 3 Co 6 S 8 also exhibit good performance preservation in conjunction with various electrolyte systems. This work highlights that SSCs are fully compatible with pentlandites and paves the way towards the realization of high efficiency and stable SSCs. Graphical abstract Ni 3 Co 6 S 8 demonstrates excellent catalytic activity towards various redox mediators, highlighting the full compatibility of pentlandites with sensitized solar cells.