Quantasol has now created GaAs [gallium arsenide] solar cells that can be tuned to the prevailing light conditions of a particular place, to get the most out of the cells wherever they are.
To do that, the firm added indium gallium arsenide (InGaAs) to pores just a few nanometres across on the surface of their cells, called quantum wells. Like the GaAs that makes up the rest of the cell, they can absorb light to produce electric current. But they do so at very specific frequencies.
The pores can be tuned to absorb light at the frequencies that are most common in a particular place but aren’t absorbed well by GaAs. Over time this strategy should extract more energy than an off-the-shelf solar cell.
In fact, this cell has achieved the first real efficiency gains in 21 years. Gallium arsenide cells are more expensive than the traditional silicon-based solar cells, but if the efficiency differences are high enough, they could actually be cost effective: