Characteristics of a dye-sensitized solar cell based on an anode combining ZnO nanostructures with vertically aligned carbon nanotubes

Electrical conductivity and a high surface area in the anode are of primary importance for the enhancement of photoelectric conversion efficiency (η) in dye-sensitized solar cells (DSSCs). This study reports on the fabrication of a DSSC anode using ZnO nanostructures. These ZnO nanostructures are coated on vertically aligned carbon nanotubes (CNTs) on stainless steel substrates using thermal chemical vapor deposition. The resulting CNTs provided a good electric connection between the ZnO overlayer and the stainless steel substrate. The photoelectric characteristics of the DSSCs were optimized with the immersion of dye for 15 hrs. Compared to the η of ZnO nanostructures on randomly distributed CNTs, the η of ZnO nanostructures on vertically aligned CNTs increased approximately 4-fold. This result showed that the vertically aligned CNTs coated with ZnO nanostructures had improved the performance of DSSC.

Research Highlights
► The resulting carbon nanotubes provided a good electric connection between the ZnO overlayer and the stainless steel substrate.
► The different dye immersion times affected the dye adsorption properties of the ZnO-coated vertically aligned carbon nanotube anode.
► This study determined the optimum dye immersion time and provided a novel strategy to improve the photoelectric conversion efficiency of dye-sensitized solar cells.