Experimental demonstrations of spontaneous, solar-driven photoelectrochemical water splitting

Laboratory demonstrations of spontaneous photoelectrochemical (PEC) solar water splitting cells are reviewed. Reported solar-to-hydrogen (STH) conversion efficiencies range from 10% STH efficiency using potentially less costly materials have been reported. Device stability is a major challenge for the field, as evidenced by lifetimes of less than 24 hours in all but a few reports. No globally accepted protocol for evaluating and certifying STH efficiencies and lifetimes exists. It is our recommendation that a protocol similar to that used by the photovoltaic community be adopted so that future demonstrations of solar PEC water splitting can be compared on equal grounds