The researchers at Hahn Meitner Institute in Berlin, Germany, have invented a new type of solar cell that is very thin and made from inexpensive materials. In collaboration with a colleague in the United States, this new device will be much cheaper to make and will use less-expensive semiconductor materials than conventional solar cells. This remarkable new breakthrough in solar cell technology had its details published in the Institute of Physics journal Semiconductor Science & Technology. The two scientists involved have used a layer of titanium dioxide that is full of tiny pores and therefore, a much more efficient device for harvesting the sun's energy.

It begins with an extremely thin layer of light-sensitive, cadmium telluride (CdTe) that forms the base for the solar cell on top of the porous titanium dioxide which is supported on a sheet of glass. On the back of this sandwich, they connected electrical contacts. The cadmium telluride layer absorbs the sunlight and the energy is converted into an electrical current which is tapped off using the electrical contacts. Inside the titanium-dioxide layer, a light bounces around inside the tiny pores and is scattered back into the cadmium-Telluride layer, thus making the device more efficient. This makes it 50 times more effective than a similar cell based on nonporous support material!

Typical solar cells produce between 0.5 and 1 V voltage. In this application, several cells are connected in series to provide higher voltage as needed. The inventors of this remarkable new solar device found if they alloyed the CdTe with mercury they could actually boost the current to 15 milliamps. Current solid-state devices can not offer the promise of renewable energy at a much lower cost, but this new invention does! There are bugs to be worked out of this new invention, but it offers promise of renewable energy at much lower cost.