Dye sensitized solar cells based on ZnO nanorod/TiO₂ nanoparticle composite films

ZnO nanorod/TiO₂ nanoparticle composite films were prepared by a sol-gel method, in which the slurry of TiO₂ nanoparticles (NPs) were penetrated into ZnO nanorod arrays. The agglomerate size of TiO² NPs was controlled with tetraethylammonium hydroxide. Lowering ZnO nanorod array density was an effective way to fill TiO₂ NPs in the space of ZnO nanorod array. The presence of ZnO and TiO₂ was confirmed by scanning electron microscopy and X-ray diffraction. Triblock copolymer (P123) was added as a template agent to obtain high specific surface area, and the solar cell performance was improved. However, the viscosity of the TiO₂ slurry was increased by addition of P123, and TiO₂ content in the composite film was reduced. Low concentration TiO2 slurry was preferable to be penetrated into ZnO nanorod array and solar cell performance was further improved.