Nanotechnology is making great contributions in various fields including harvesting solar energy through solar cells since nanostructured solar cells can provide high performance with lower fabrication costs. The transition from fossil fuel energy to renewable sustainable energy represents a major technological challenge for the world. The solar cells industry has grown rapidly in recent years due to strong interest in renewable energy in order to handle the problem of global climate change that is now believed to occur due to the use of fossil fuels. Cost is an important factor in the eventual success of any solar technology since inexpensive solar cells are needed to provide electricity especially for rural areas and for underdeveloped countries. Therefore, new developments in nanotechnology may open the door to the production of cheaper and more efficient solar cells by reducing the manufacturing costs of solar cells. This chapter covers a review of the progress that has been made to-date to enhance efficiencies of various nanostructures used in solar cells including utilizations of all the wavelengths present in of the solar spectrum.