Morphology-controlled growth of NiCo2O4 ternary oxides and their application in dye-sensitized solar cells as counter electrodes

- NiCo2O4 nanosheets, nanotods and nanoflowers have been synthesized.
- NiCo2O4 nanoflowers achieved a excellent PCE of 8.48%.
- This study offers a self-assembled synthetic route to prepare NiCo2O4 nanoflowers.
- The NiCo2O4 nanoflowers demonstrated remarkable catalytic activity.

In this article, ternary oxides NiCo2O4 with morphologies of nanosheets, nanorods and nanoflowers have been synthesized by the thermal treatment of the precursors which were fabricated via a hydrothermal process. The materials were then used as counter electrodes (CEs) in dye-sensitized solar cells (DSSCs). The DSSCs equipped with NiCo2O4 nanoflowers CE achieved excellent power conversion efficiency (PCE) of 8.48%, which is higher than that of counter parts of NiCo2O4 nanosheets (3.57%), NiCo2O4 nanorods (6.84%) and Pt (8.11%) CEs. Transmission electron microscopy image shows that the NiCo2O4 nanoflowers have the best porous 3-dimensional spatial structure. This study offers a self-assembled synthetic route to prepare NiCo2O4 nanoflowers. The unique structure exhibits high efficient performance and excellent catalytic activity, which may open a new window to use ternary oxides for greatly extending potential applications in dye-sensitized solar cells and other related fields.

We propose a facile process to fabricate NiCo2O4 nanosheets, nanotods and nanoflowers. The NiCo2O4 nanoflowers demonstrated remarkable electrocatalytic ability and faster kinetic reduction capability. And the photovoltaic performance of NiCo2O4 nanoflowers is higher than the Pt.137