Solar concentrator, artwork. The inset images show how a cost-effective solar concentrator (on roof at lower left) can help make existing technology more efficient. The inset at upper centre shows an upper layer of solar cells producing a high voltage, and a lower layer of those producing a low voltage. The inset at lower right shows how dye molecules on the upper, glass layer absorb sunlight, and re-emit it at a different wavelength. The light is trapped and transported within the glass until it is captured by solar cells at the edge. Some light passes through the concentrator, and is absorbed by lower voltage solar cells underneath. Image published in 2008.