Efficiency improvement of TiO2 nanowire arrays based dye-sensitized solar cells through further enhancing the specific surface area

Abstract

Vertically aligned nanowire arrays (NWAs) assembled by monocrystalline rough-surface rutile TiO2 nanowires have been prepared by simple solvothermal methods. Compared with smooth-surface TiO2 NWAs, the large specific surface area of rough-surface TiO2 NWAs is more beneficial to dye absorption which is closely related to the photoelectric conversion efficiency (PEC) of dye-sensitized solar cells (DSSCs). The PEC of DSSCs based on the rough-surface TiO2 NWAs we prepared could reach 8.28%. Prolonging the etching treatment time could increase the specific surface area of TiO2 NWAs, but meanwhile the increased photogenerated electron recombination caused by more contact area between photoanode and electrolyte would decrease the PEC of DSSCs. Furthermore, in combination with a light-scattering layer, the performance of the rough-surface rutile TiO2 NWAs based DSSC can be further enhanced, reaching an impressive PCE of 9.39%, which is a remarkable conversion efficiency for DSSCs based on rutile TiO2 NWAs heretofore.