Oxide semiconductor materials for solar light energy utilization

Two approaches for harvesting solar light energy effectively using oxide semiconductor materials are introduced. The one is water splitting using new types of oxide semiconductor photocatalyst systems. By Na2CO3 addition method, it was firstly demonstrated that water is decomposed to H-2 and O-2 steadily and stoichiometrically using NiO/TiO2 photocatalyst under the solar light. A new two-step water splitting system using photocatalysis is also introduced. The other is dye-sensitized oxide semiconductor solar cells in order to convert visible light energy to electricity. Combinations of various types of oxide semiconductors and organic dyes, such as Eosin-Y, suggests the appearance of promising and cheap solar cells.