Tuning Interfacial Electron Transfer in Nanostructured Cuprous Oxide Photoelectrochemical Cells with Charge-Selective Molecular Coatings

The coating of nanostructured films of cuprous oxide with electroactive molecules strongly affects their photoelectrochemical performance in nonaqueous photocells, with photocurrent density increased up to an order of magnitude relative to bare cuprous oxide films or almost completely suppressed, depending on the choice of molecular adsorbant. Among adsorbants that enhance photocurrent, a strong variance of photoelectrochemical behavior is observed with changes in the molecular structure of the sensitizer, associated with differences in the reorganization energy and molecular size, which are interpreted to enhance forward electron transport and impede electrolyte/photocathode recombination, respectively. These results demonstrate that nanostructured cuprous oxide is a promising cathode material for p-type dye-sensitized solar cells.