Hexagonal ZnO nanodisks, nanorings and porous nanodisks were synthesized by a simple hydrothermal method. The morphologies, structure and their optical properties of the various ZnO disk-like structures were characterized and their growth mechanism was investigated. The prepared ZnO disk-like nanostructures were used in the fabrication of the dye-sensitized solar cells. Improved photovoltaic properties were achieved for the porous disk solar cells due to their special geometry enabled better light harvesting and reduced recombination.