Talk about a speculator's twofer! From the Economist:
MAKERS of solar cells face a dilemma. Purified silicon, the basic material of such cells, is expensive. The temptation, therefore, is to use less of it. As a result, the makers have developed a generation of cells whose silicon layers are only a micron or two deep, as opposed to the usual thickness of 200-300 microns. The thinner the cell, however, the less efficient it is. In particular, thin cells fail to capture much light at the red end of the spectrum. That means they produce up to 20% less electricity than standard cells of equivalent area. And that negates some of the advantage of their initial cheapness.
To remedy this problem, Kylie Catchpole of the Australian National University in Canberra and Albert Polman of the Institute for Atomic and Molecular Physics in Amsterdam have been trying to redirect the light that falls onto the surface of a cell in such a way that all colours are efficiently absorbed. Their chosen tools for this task are tiny particles of silver....MORE