Mesoporous NiCoO nanoflower constructed from nanosheets as electroactive materials for dye-sensitized solar cells.

Binary metal compounds with a spinel structure could improve the electron transport, activating adsorption and active sites for electrocatalytic reaction. Furthermore, the electrocatalytic activity of electroactive materials also depends on their morphology and nanostructure. Herein, this work reported the fabrication of NiCoO mesoporous nanoflowers and mesoporous nanospheres and their application as promising counter electrode (CE) electrocatalysts in dye-sensitized solar cells (DSSCs). The as-prepared NiCoO mesoporous nanoflower contains abundant open space between nanosheets, generating the 3D porous nanostructure. When investigated as CE materials, NiCoO nanoflowers exhibited high charge-transfer ability and intrinsic catalytic activity. The DSSC with NiCoO nanoflowers displayed a much higher power conversion efficiency (PCE) of 7.32% than that based on the NiCoO nanosphere CE (PCE = 5.58%), even comparable with that of commercial Pt CE (7.54%).