Application of a Schottky barrier to dye-sensitized solar cells (DSSCs) with multilayer thin films of photoelectrodes

► Au and TiO 2 nanoparticles are to combine to form a Schottky barrier. ► Titanium nanotubes prepared by using hydrothermal treatment. ► TiO 2 nanoparticles prepared by subjecting Tnt to two cycles of hydrothermal treatment. ► Three layers of photoelectrode thin films enhanced the photoelectric efficiency of DSSCs by as high as 21%. This study combines Au nanoparticles with TiO 2 nanoparticles to form a Schottky barrier, and applies it to the photoelectrode thin film of dye-sensitized solar cells (DSSCs). First, commercial TiO 2 powder (Degussa P25) is put in the alkaline solution to prepare for TiO nanotubes (Tnt) by using hydrothermal treatment. Tnt are sintered at 550 °C to obtain Tnt-C550 particles. In addition, TiO 2 nanoparticles (H180) prepared by subjecting Tnt to two cycles of hydrothermal treatment. H180 served as the first layer, and Tnt-C550 as the second. The third layer adopts salt reduction method to prepare for Au nanoparticles. Experimental results show that the DSSCs prepared with three layers of photoelectrode thin films (H180/Tnt-C550/Au) enhanced the light-to-electricity efficiency of DSSCs by as high as 21% (6.34–7.65%).