Bipolar CdSe/CoS semiconductor photoelectrode arrays for unassisted photolytic water splitting

Bipolar CdSe/CoS semiconductor photoelectrode panels, capable of vectorial electron transfer, have been used in series arrays to photodecompose water to yield hydrogen and oxygen in stoichiometric ratio with a maximum equivalent solar efficiency of about 1%. The use of bipolar photoelectrode arrays obviates the problems of the location of the semiconductor band edges relative to the water decomposition potentials and the requirement of semiconductor stability during photohole generation and oxygen production in aqueous solutions.