A solar cell absorbs a small range of light wavelengths based upon the density and width of silicon crystals. Light strikes the crystals and causes electrons to propagate along the network. We call this flow of electrons electricity.
More crystals of different widths in the network mean that more different wavelengths can be absorbed and more power can be generated. Adding different layers of crystals to absorb a wider range of wavelength is one way to increase the power, but the process to spread these crystals over a surface is very expensive and energy intensive.
Prism Solar Technologies is going a different path by splitting the incoming sunlight and concentrating specific wavelengths onto a variety of cells designed to collect those specific wavelengths, yielding 25% greater electricity yields. These concentrators and splitters are orders of magnitude cheaper to produce than solar cells and increase the power of each solar cell. Oh, by the way, the Prism splitter is clear.