Bilayer electrode composition of TiO₂ film for dye-sensitized solar cell

Abstract
Nano-porous TiO₂ film as a photoelectrode plays an important role in dye-sensitized solar cell. The TiO₂ film is generally prepared from precursor paste including TiO₂ nano particles by heating. Additives in the precursor paste and "bilayer" compositions of TiO₂ films were studied. The reflectance of TiO₂ film prepared from nitric-acid added paste was higher than that from acetylacetone-added paste over visible light region. Energy conversion efficiency of cell using the former film as single layer electrode is low. However, in the case of bilayer, electrode consisting of film prepared from nitric-acid added paste on the substrate side showed much increase of efficiency compared with acetylacetone-added film. It is considered that nitric acid improves the electric contact of TiO₂ layers.