SOLAR ENERGY:IBM HAS developed a solar cell with a light absorption layer made of cheaper, readily available metals rather than the rare, more expensive metals currently being used in thin film solar cell modules.
The thin film solar cell modules currently on offer are based upon compound semiconductors which operate at 9 to 11 per cent efficiency levels, and are primarily made from two costly compounds – copper indium gallium selenide or cadmium telluride.
In contrast IBM’s new cell is comprised of copper, tin, zinc, sulphur or selenium, all of which are relatively abundant earth metals. It has achieved a 9.6 per cent efficiency rating, which is about 40 per cent better than earlier attempts using these materials.
The solar cell development also sets itself apart from its predecessors as it was created using a combination of solution-based and nanoparticle-based approaches, rather than the popular – but expensive – vacuum-based technique.
This is expected to lower production costs and make the manufacturing process - which involves printing, dip and spray coating and slit casting - faster, less wasteful and more efficient.
