Effective photogeneration in TiO2/VO2/TiO2 multilayer film electrodes prepared by a sputtering method

The effective separation of photogenerated electrons and holes in the TiO2/VO2/TiO2 multilayer film electrodes prepared by a sputtering method is studied, in which a very thin VO2 layer is inserted into the space charge layer of a TiO2 electrode. An enhanced photogeneration is observed by inserting the thin VO2 layer of ~2 nm in thickness at a position where the electric field gradient is considered to be large and by adjusting the Fermi level of the system to the 3d-levels of V (super 4+).