Welsh solar cells are not based on silicon which makes them very inexpensive

Via Phila of Bouphonia's Friday Hope Blog:

Their solar cell works in a different way from most, and is not based on silicon - the expensive raw material for conventional solar cells. G24 Innovations (G24i), the company making the new cells, says it can produce and sell them for about a fifth of the price of silicon-based versions. At present, it makes only small-scale chargers for equipment such as mobile phones and MP3 players. But it says larger panels could follow - large enough to replace polluting fossil fuels by generating electricity for large buildings.

"This has been at the laboratory stage for 18 years and now we are ready to take it into a huge amount of applications," says Clemens Betzel, president of G24i.

G24i's technology is based on a coloured dye and tiny crystals of titanium oxide - a common pigment in white paint. It exploits a discovery made in 1991 by a Swiss chemist called Michael Graetzel, who found that the combination could be used to copy photosynthesis. When struck by sunlight, the dye spits out an electron, which is immediately captured by the specks of titanium oxide. By collecting the electrons at one side of his new solar cell, and replacing them at the other with an iodide electrolyte solution, Graetzel produced an electric current.

The new so-called Graetzel cells offered a simpler and potentially cheaper way to generate solar power. (Traditional silicon cells are more complicated because they require the generation of an electric field within the silicon to carry away the liberated electrons.) And because they work in a different way, Betzel says the new cells offer other advantages too. They work better in low light levels, including indoors, he says, and they are lighter and less fragile than silicon cells, which are usually mounted on glass or rigid plastic.