Film photoelectrodes

Claim 1

A photoactive film electrode comprising: a substrate; an electrical connector, and a film layer comprising a photoactive true solid/solid solution semiconductor mixed metal oxide material containing metal components all of which are derived from precursor substances selected from the group consisting of elemental metals, non-oxide metal compounds, and mixtures thereof; said mixed metal oxide material corresponding to the formula A r va M y vm O z -2 ; where said formula represents the stoichiometry of the basic repeating unit lattice cell; where M is the combination of component (a) metal and component (b) metal; A when present is at least one different metal which does not substantially alter the optical absorption accruing from M in the above formula; O represents oxygen, said formula being further characterized in that r, y, z, va and vm are defined by the relationship va(r)+vm(y)=2z, wherein r equals a value of from 0 to 2, inclusive, y is from 1 to 2, inclusive, z is from 1 to 7, inclusive, va equals the positive valence of A, vm equals the positive mean valence of M and the valence of oxygen is -2; and wherein all said metal components of said formula are selected from the group consisting of boron, aluminum, tin, lead, the transition metals of families 1b through 7b, inclusive, and 8 of the periodic table of elements and the lanthanide series; wherein M in the above formula comprises: (a) 50 to 99.9 mole percent, based on the total metals mole fraction, of one or more component (a) metals; and (b) 0.1 to 50 mole percent, based on the total metals mole fraction, of one or more component (b) metals; with the proviso that said component (b) metals are different than said component (a) metals and with the further proviso that said component (a) metals, when in comparable oxide form, have a larger band gap than said component (b) metals, when said component (b) metals are in their comparable oxide form; wherein said photoactive true solid/solid solution semiconductor mixed metal oxide material's optical absorption edge is thereby optimized to approximately 800 nanometers, corresponding to a band gap of about 1.4 eV.