Solar cells are made of layers of several different semiconductors stacked together to absorb nearly 40 percent light at different wave lengths. Commercially available solar cells have much lower efficiencies (15-20%). Nanotechnology could help increase the efficiency of light conversion by using nanostructures with a continuum of bandgaps. Scientists have recently developed tetrad-shaped nanoparticles that, when applied to a surface, instantly transform it into a solar collector. Nanocrystals are an ideal light harvester in photovoltaic devices that absorb sunlight more strongly than dye molecules or bulk semiconductor material, therefore high optical densities can be achieved while maintaining the requirement of thin films.In the new area of solar cells research using dye-sensitized materials, cells are unique as they mimick photosynthesis, using TiO2 nanoparticles, dyes and electrolyte. Although these cells produce a modest 11% efficiency they are still plagued with practical challenging such as electrolyte leakage and cell stability due to TiO2 - dye interactions. Solar cell made using Si nanowires to reduce Si quantity (as its cost has increased due to dramatic Si solar cell demand increase) using plasmonics to confine solar energy can reduce film thickness.