Cuprous oxide (Cu2O) nanorod arrays have been prepared via a novel templated electrodeposition process and were characterized for their photocatalytic behavior in nonaqueous photoelectrochemical cells. Zinc oxide (ZnO) nanorod films serve as sacrificial templates for the in situ formation of polymer nanopore membranes on transparent conductive oxide substrates. Nitrocellulose and poly(lactic acid) are effective membrane-forming polymers that exhibit different modes of template formation, with nitrocellulose forming conformal coatings on the ZnO surface while poly(lactic acid) acts as an amorphous pore-filling material. Robust template formation is sensitive to the seeding method used to prepare the precursor ZnO nanorod films. Photoelectrochemical cells prepared from electrodeposited Cu2O films using methyl viologen as a redox shuttle in acetonitrile electrolyte exhibit significant charge recombination that can be partially suppressed by a combination of surface passivation methods. Surface-passivated nanostructured Cu2O films show enhanced photocurrent relative to planar electrodeposited Cu2O films of similar thickness. We have obtained the highest photocurrent ever reported for electrodeposited Cu2O in a nonaqueous photoelectrochemical cell.

An unsymmetrical (A3B) palladium porphyrin bearing a cyanoacrylic acid at one meso position has been synthesized for evaluation as a photosensitizer in dye-sensitized solar cells based on titanium dioxide ( TiO 2) as a comparison to other metalloporphyrins and as a proxy for other potential triplet-state photosensitizer compounds. The synthesis of this palladium porphyrin has provided new insight into the mechanism and product distribution of decarboxylative hydrolysis of malonic acid when attached at the porphyrin meso position. A crystal structure determination for a meso-formyl palladium porphyrin has been determined, showing saddle-distortion of the porphyrin core. The photophysical behavior of the palladium porphyrin sensitizer and its performance in photoelectrochemical cells are described and interpreted in the context of bimolecular excited state quenching pathways including oxygen sensitization, triplet–triplet annihilation and electron transfer events. Palladium porphyrins are proposed as a sensitizer class with potential for high efficiency dye-sensitized solar cells, but with the caveat that some overpotential for electron injection is necessary to compete against the multiple decay pathways that are specially available to triplet state photosensitizers.