I can surgest a book Materials for Sustainable Energy: A Collection of Peer-Reviewed Research and Review Articles from Nature Publishing Group, 2011, Vincent Dusastre
World Scientific. This would form an interesting introduction into solar cell based research.
The ability to tune the bandgap is what makes quantum dots desirable for solar cell use. QDs absorb photons of a shorter wavelength (blue region) and emit them back at a longer wavelength (red region) where the device has high quantum efficiency. This enhances the photo response and efficiency of the cell.
There is some link which could be useful in this area:-