A new method for manufacturing solar cells could halve the cost of converting the sun’s rays to electricity, its UK developers claimed this week.
The technique, under investigation at the University of Bath, is based on the use of electroplating processes more typically used in metal finishing applications such as chrome plating to produce thin-film solar cells.
Electroplating is the process of attaching a metallic coating to a bar surface through the use of a liquid solution or other substance, which conducts electricity.
Most commercially available solar cells are made from very pure wafers of either polycrystalline or monocrystalline silicon. such cells can exhibit efficiencies of around 20 per cent, but the financial and environmental cost of making a pure silicon wafer is high.
Many claim it is this that has prevented solar power from fulfilling its potential as a clean and reliable competitor to grid-supplied electricity from conventional sources.
An alternative is to deposit a thin layer of semiconductor material on to a supporting material such as glass. The Bath team is looking into the use of existing electroplating methods to deposit copper indium sulphide and copper indium gallium sulphide, both of which are semiconducting materials, on to large area panels.
Prof Laurie Peter, who is heading the Bath project, explained that while the high-temperature silicon solar cell fabrication processes are expensive, electroplating can be scaled up at relatively low cost.
He added that the material is deposited only on the object that is connected to a voltage source so there is very little waste, and the thickness of the deposited film is also extremely simple to control via the current and deposition time.
In addition to the efficiency of the process, Peter also claimed that electroplating has environmental benefits. The solutions used for the electroplating process are easily stored and handled, and the recycling of the liquids is straightforward, he said.