Improvement of photoelectric conversion efficiencies of dye‐sensitized solar cells consisting of hemispherical TiO2 films

To improve the photoelectric conversion efficiency (PCE) of dye‐sensitized solar cells (DSSCs), we fabricated hemispherical TiO2 films using a poly(dimethylsiloxane) mold and improved the light harvesting efficiency in DSSCs by a large light‐scattering effect caused by the hemispherical structure. In addition, the amount of the adsorption density of the dye in TiO2 increased due to the larger surface area of the hemispherical structure. Consequently, the short‐circuit current of DSSCs containing hemispherical TiO2 film increased even though the open‐circuit voltage was not changed. As a result, the overall PCE value was improved to about 1.2 times larger than a DSSC containing a flat TiO2 film. In addition, polyethylene glycol‐doping in TiO2 effectively improved the DSSC performance comprised of hemispherical TiO2 films.