Abstract: A photocatalyst material and a photocatalyst device capable of generating hydrogen from water by radiation of sunlight at high efficiency. The photocatalyst material according to the present invention includes a nitride-based compound semiconductor obtained by replacement of part of Ga and/or Al by a 3d-transition metal. The nitride-based compound semiconductor has one or more impurity bands. A light absorption coefficient of the nitride-based compound semiconductor is 1,000 cm?1 or more in an entire wavelength region of 1,500 nm or less and 300 nm or more. Further, the photocatalyst material satisfies the following conditions: the energy level of the bottom of the conduction band is more negative than the redox potential of H+/H2; the energy level of the top of the valence band is more positive than the redox potential of O2/H2O; and there is no or little degradation of a material even when the material is irradiated with light underwater.

Abstract: There is provided a new light-absorbing material and a photoelectric conversion element using the same, which are capable of improving conversion efficiency of a solar cell. The light-absorbing material in the present invention is made up of a GaN-based compound semiconductor with part of Ga replaced by a 3d transition metal, and has one or more impurity bands, and whose light absorption coefficient over an overall wavelength region of not longer than 1500 nm and not shorter than 300 nm is not lower than 1000 cm?1.

Abstract: A photocatalyst material and a photocatalyst device capable of generating hydrogen from water by radiation of sunlight at high efficiency. The photocatalyst material according to the present invention includes a nitride-based compound semiconductor obtained by replacement of part of Ga and/or Al by a 3d-transition metal. The nitride-based compound semiconductor has one or more impurity bands. A light absorption coefficient of the nitride-based compound semiconductor is 1,000 cm?1 or more in an entire wavelength region of 1,500 nm or less and 300 nm or more. Further, the photocatalyst material satisfies the following conditions: the energy level of the bottom of the conduction band is more negative than the redox potential of H+/H2; the energy level of the top of the valence band is more positive than the redox potential of O2/H2O; and there is no or little degradation of a material even when the material is irradiated with light underwater.

Abstract: A new light-absorbing material which can increase the conversion efficiency of a solar cell and a photoelectric conversion element using same are provided. The light-absorbing material of the present invention comprises a nitride-based compound semiconductor obtained by replacement of part of Al and/or Ga in a compound semiconductor expressed by a general formula Al1?yGayN (0?y?1) by at least one kind of 3d-transition metals, the nitride-based compound semiconductor having one or more impurity bands between a valence band and a conduction band, and whose light absorption coefficient over an overall wavelength region of not longer than 1500 nm and not shorter than 300 being not lower than 1000 cm?1.

Abstract: There is provided a new light-absorbing material and a photoelectric conversion element using the same, which are capable of improving conversion efficiency of a solar cell. The light-absorbing material in the present invention is made up of a GaN-based compound semiconductor with part of Ga replaced by a 3d transition metal, and has one or more impurity bands, and whose light absorption coefficient over an overall wavelength region of not longer than 1500 nm and not shorter than 300 nm is not lower than 1000 cm?1.