Preparation of Multilayer TiO2 Thin Films for Dye-Sensitized Solar Cells

Abstract

We adopt TiO2 materials with three different morphologies to fabricate multilayer thin films for dye-sensitized solar cell (DSSC) photoelectrodes. The three different TiO2 morphologies are (1) titania nanotubes (Tnt) hydrothermally fabricated by 550 °C calcinating treatment to form an anatase phase (Tnt-C550), (2) TiO2 nanoparticles (H200) prepared by subjecting Tnt to two cycles of hydrothermal treatment, and (3) a TiO2 nanofluid (SF) fabricated by our developed submerged arc nanofluids synthesis system (SANSS). Experimental results showed that DSSCs fabricated with Tnt photoelectrodes tested with AM 1.5 light to simulate sunlight (100 mW/cm2) had a photoelectric conversion efficiency of 2.84%. The thin-film photoelectrode was prepared using Tnt-C550 calcined at 550 °C. Its photoelectric conversion efficiency increased to 5.77%. The photoelectric conversion efficiency of DSSCs with photoelectrodes fabricated using H200 reached 5.91%. Moreover, the photoelectric conversion efficiency of DSSCs with photoelectrodes prepared using SF reached 4.45%. Finally, the TiO2 materials with three different morphologies were used to prepare a three-layer photoelectrode with the structure of H200/Tnt-C550/SF, which was combined with a counter electrode to assemble DSSCs. These DSSCs had a photoelectric conversion efficiency of as high as 7.07%.