Scientists believe that fly eyes are perfectly shaped for manufacturing efficient solar cells. Specifically, copying the eye of the Blowfly would allow solar cells to "collect sunlight from a larger area than just light that falls directly on a flat surface".
Blowflies are desirable because their eyes are hemispherical. More importantly, within each half sphere, the surface is covered by "macroscale hexagonal eyes with nanoscale features". Basically they have the ability to take in a whole lotta light from a lot of different angles.
In order to replicate the blowfly's eye, a group of scientists took the corneas of nine flies and filled them with a polymer to maintain its shape. Then they mounted the cornea on glass and coated them with nickel. This process allowed them to create a mould with the exact pattern of a fly's eye. With these moulds, scientists expect future solar cells to be built with fly eyes to maximise efficiency. I hope they're less gross looking. [Wired.uk]