ZnO hierarchical nanostructures and application on high-efficiency dye-sensitized solar cells

Uniform hierarchical ZnO nanostructures are synthesized on a large scale based on a solution approach at low temperature. The primary ZnO hexagonal prisms are firstly produced by the reaction of Zn(NO3)2 with hexamethylenetetramine, and then ZnO branches grow on the primary prisms by using ethylenediamine molecules as an evocator. The morphology of the hierarchical nanostructure can be controlled conveniently by adjusting the molar ratio of [EDA]/[Zn2+]. The hierarchical structure provides an effective pathway for carrier transport as well as larger surface area for dye adsorption, when ZnO hierarchical nanostructures serve as photoanode materials, the solar cells show higher conversion efficiency than that of primary ZnO nanowires.