solar cells tuned to their location

The new Quantasol gallium arsenide solar cells are more efficient than the common silicon solar cells but do so at specific light frequencies. The cells have been engineered to allow them to be tuned to the light conditions at their location. From the New Scientist article:

That may only be one-tenth of a percentage point higher than the previous world-record holder, but it's the first advance in 21 years. Commercial silicon solar cells are much cheaper than GaAs, but have an efficiency of just 10 to 12 per cent and are also bulkier. The Quantasol device can cope with much brighter light without becoming overloaded, making it possible to use a very small solar cell to absorb light collected by a system of cheap lenses and mirrors.

Gallium is a by-product of aluminum or zinc refinement, and arsenic from copper or gold refinement. I wish I knew more about the energy debt incurred in making a solar cell, and more about the pollution, etc. involved with making these versus silicon chips.