Photoelectrochemical cell and energy system using the same

Abstract

A photoelectrochemical cell () includes: a semiconductor electrode () including a conductor () and an n-type semiconductor layer (); a counter electrode () connected electrically to the conductor (); an electrolyte () in contact with the surfaces of the n-type semiconductor layer () and the counter electrode (); and a container () accommodating the semiconductor electrode (), the counter electrode () and the electrolyte (). The photoelectrochemical cell () generates hydrogen by irradiation of the n-type semiconductor layer () with light. In the semiconductor electrode (), relative to the vacuum level, (I) the band edge levels of the conduction band and the valence band in the surface near-field region of the n-type semiconductor layer (), respectively, are equal to or higher than the band edge levels of the conduction band and the valence band in the junction plane near-field region of the n-type semiconductor layer () with the conductor (), (II) the Fermi level of the junction plane near-field region of the n-type semiconductor layer () is higher than the Fermi level of the surface near-field region of the n-type semiconductor layer (), and (III) the Fermi level of the conductor () is higher than the Fermi level of the junction plane near-field region of the n-type semiconductor layer ().