Xiang C.,210 Noyes Laboratory |
Kimball G.M.,210 Noyes Laboratory |
Grimm R.L.,210 Noyes Laboratory |
Brunschwig B.S.,210 Noyes Laboratory |
And 2 more authors.
Energy and Environmental Science | Year: 2011
P-Type cuprous oxide (Cu2O) photoelectrodes prepared by the thermal oxidation of Cu foils exhibited open-circuit voltages in excess of 800 mV in nonaqueous regenerative photoelectrochemical cells. In contact with the decamethylcobaltocene+/0 (Me10CoCp2 +/0) redox couple, cuprous oxide yielded open-circuit voltage, V oc, values of 820 mV and short-circuit current density, J sc, values of 3.1 mA cm-2 under simulated air mass 1.5 illumination. The energy-conversion efficiency of 1.5% was limited by solution absorption and optical reflection losses that reduced the short-circuit photocurrent density. Spectral response measurements demonstrated that the internal quantum yield approached unity in the 400-500 nm spectral range, but poor red response, attributable to bulk recombination, lowered the overall efficiency of the cell. X-Ray photoelectron spectroscopy and Auger electron spectroscopy indicated that the photoelectrodes had a high-quality cuprous oxide surface, and revealed no observable photocorrosion during operation in the nonaqueous electrolyte. The semiconductor/liquid junctions thus provide a noninvasive method to investigate the energy-conversion properties of cuprous oxide without the confounding factors of deleterious surface reactions. © 2011 The Royal Society of Chemistry.