Synthesis of Amorphous Er 3+ -Yb 3+ Co-doped TiO 2 and Its Application as a Scattering Layer for Dye-sensitized Solar Cells

TiO2 doped with Er3+ and Yb3+ was used for fabricating a scattering layer and a nano-crystalline TiO2 electrode layer to be used in dye-sensitized solar cells. The material was prepared using a new sol-get combustion hybrid method with acetylene black as fuel. The Er3+-Yb3+ co-doped titanium oxide powder synthesized at 700 degrees C had embossed structure morphology with a size between 27 to 54 nm that agglomerated to produce micron size particles, as observed by the scanning electron micrographs. The XRD patterns showed that the Er3+-Yb3+ co-doped titanium oxide had an amorphous structure, while using the same method without doping Er3+ or Yb3+, TiO2 was obtained in the crystallite form with thea dominance of rutile phase. Fabricating a bilayer structure consisting of nano-crystalline TiO2 and the synthesized Er3+-Yb3+ co-doped titanium oxide showed better scattering property, with an overall increase of 15.6% in efficiency of the solar cell with respect to a single nano-crystal line TiO2 layer