Multistep electrochemical deposition of hierarchical platinum alloy counter electrodes for dye-sensitized solar cells

•PtM (M = Ni, Fe, Co) alloy CEs are synthesized by a multistep electrodeposition.•The resultant PtM alloy CEs are fabricated into DSSCs.•The PtM alloy CEs have markedly enhanced catalytic activity.•The optimized DSSC yields a maximum efficiency of 8.65%.

The preferred platinum counter electrode (CE) has been a burden for commercialization of dye-sensitized solar cell (DSSC) due to high expense and chemical corrosion by liquid electrolyte. In the current study, we have successfully realized the multistep deposition of platinum alloy CEs including PtNi, PtFe, and PtCo for liquid-junction DSSC applications. The preliminary results demonstrate that the enhanced electrochemical activities are attributable to high charge-transfer ability and matching work functions of the PtM (M = Ni, Fe, Co) alloy CEs to redox potential of I−/I3− electrolyte. The resultant DSSCs yield impressive power conversion efficiencies of 8.65%, 7.48%, and 7.08% with PtNi, PtFe, and PtCo CEs, respectively. On behalf of the competitive reactions between transition metals with liquid electrolyte, the PtM alloy CEs display enhanced long-term stability.