Enhanced Performance of Supported HfO2 Counter Electrodes for Redox Couples Used in Dye-Sensitized Solar Cells

Mesoporous-graphitic-carbon-supported HfO2 (HfO2-MGC) nanohybrids were synthesized by using a soft-template route. Characterization and a systematic investigation of the catalytic properties, stability, and catalytic mechanism were performed for HfO2-MGC counter electrodes (CEs) in dye-sensitized solar cells (DSSCs). The new HfO2-MGC as a CE in DSSCs showed a surprisingly high efficiency of 7.75% for the triiodide/iodide redox couple and 3.69% for the disulfide/thiolate redox couple, greater than the Pt electrode in the corresponding electrolyte system, which opens up a possibility for its practical application.