Abstract: The deposition of a thin insulating layer around the TiO₂ film to form a"core-shell"structure is a promising approach for the modification of electrodes. This is currently one of the focuses in the dye sensitized solar cell (DSC), which has received much attention for development of low-cost and simple assembly technology. In this paper, yttrium oxide (Y₂O₃), as a shell material, was coated onto the TiO₂ film by a dipping method. The Y₂O₃/TiO₂"core-shell"electrode was then used to fabricate the DSC. The composition and structure of the Y₂O₃/TiO₂ film were measured. The effects of the Y₂O₃ layer on the flat-band potential, electron recombination, and the characteristics of DSC were investigated in detail. Results suggest that the flat-band potential of the film shifted negatively when TiO₂ was coated with Y₂O₃ while electron recombination loss at the TiO₂/electrolyte/dye interface was effectively reduced. As a result, the"core-shell"electrode provided a longer electron lifetime value compared with the uncoated TiO₂ electrode and ultimately the open-circuit voltage increased dramatically. Studies show that the cell performance can be improved by the introduction of a proper amount of Y₂O₃ to the DSC.

Key words: Yttrium oxide, Electron recombination, Flat-band potential, Dye sensitized solar cell