A Californian company, Twin Creeks Technologies, has developed a technology which it claims could halve the cost of pphotovoltaic cells and make solar pv technology price competitive with fossil fuels.
Currently, most photovoltaic cells are made by slicing blocks of silicon into 200 micron thick wafers. Electrodes are attached and the silicon wafers are covered with protective glass.
Because silicon crystals are brittle, it cannot be sliced thinner than 200 microns. And the process of slicing it wastes almost half of the silicon as "sawdust".
In the Twin Creeks technology, standard wafers of silicon are bombarded with high energy protons. The protons embed themselves precisely 20 microns below the surface of the silcon. This allows ultra-thin laminas of silicon, 20 microns thick, to lift off. The original silicon wafer is re-used to produce more ultra-thin laminas.
The silicon laminas are then attached to a metal backing.
Twin Creeks Technologies claims that this process can produce solar cells for about 40 cents per watt – about half the current price.
To achieve this, Twin Creeks has developed its own particle accelerator which it says can process over 1.5 million thin wafers a year, enough for more than 6 megawatts worth of solar cells.