NiCo2O4 Nanostructures as a Promising Alternative for NiO Photocathodes in p‐Type Dye‐Sensitized Solar Cells with High Efficiency

NiCo2O4 nanostructures were directly grown on fluorine‐doped tin oxide (FTO) conductive substrates by using a facile, low‐temperature hydrothermal process and their morphology was precisely adjusted from nanowires (NW) to nanosheets (NS) and novel nanowire‐woven nanosheet (NW–NS) arrays. Such nanostructures were then explored for photoelectrodes of p‐type dye‐sensitized solar cells (DSSCs), in which the conversion efficiency demonstrated a strong dependence on the morphology. NiCo2O4 NW–NS based p‐DSSCs showed a high conversion efficiency of 0.785 %, which is higher than the values reported for NiO and other materials in p‐DSSCs based on the classical I3−/I− electrolyte. The mechanism of enhanced performance was analyzed in detail and mainly attributed to synergistic effects in the photoelectrodes, with a significantly improved efficiency of light harvesting and fast hole transport.