IBM, Broadband up efficiency and drop costs with thin-film solar experiments

Recent advances in materials and design have resulted in thin-film solar modules that are more efficient and affordable than ever. Now IBM has developed its own thin-film product that uses common metals instead of pricey silicon. And a Stanford spinoff called Broadband Solar is using cheaper amorphous silicon coatings toward the same end.
Amorphous silicon coatings have been proven to up solar module efficiency by as much as 50 percent during advanced testing, according to Broandband. Containing nanoscale metallic particles, they actually absorb more sunlight, the company claims. Competitively priced with standard gallium-indium coatings, the amorphous silicon (which is more plentiful of a material) regularly increases module efficiency from 8 percent to 12 percent — a substantial change. Conveniently, the new coatings can be applied with the same machinery that has always been used in thin-film manufacturing plants.
It’s unlikely that Broadband will produce its own thin-film, or panels. It will probably make the bulk of its revenue by licensing its coating technology to other companies. By applying the company’s coatings, lesser-known thin-film makers could potentially achieve efficiencies equal to those reached by top dog First Solar at a reduced cost.
IBM’s alternative thin-film chemistry (pictured above), on the other hand, has a slightly lower efficiency rating — converting 9.6 percent of the sunlight absorbed into energy, compared to the 11 percent achieved by most commercial thin-film modules. However, similar metal films have hit efficiencies of nearly 20 percent during laboratory testing.
What makes IBM’s new product special is that it is 40 percent more efficient than typical common-metal modules, which are much cheaper than their silicon competitors. The computing giant plants to continue development of its copper, zinc, tin, sulfur and selenium concoction until it tops a 12 percent efficiency. At that point, its modules would be much more powerful and a lot cheaper than many of the market leaders.
In addition to being much cheaper, the materials in IBM’s pioneering thin-film are much greener too. Current technologies using cadmium, tellurium, gallium and indium aren’t easy to recycle, and have previously resulted in toxic contamination problems.
Like Broadband, IBM isn’t interested in manufacturing its own solar panels either — it will also be licensing its thin-film design to companies that are equipped to churn out utility-scale volumes of photovoltaics. Now if only Broadband’s coating could be applied to IBM’s eventual material, a veritable uber-film could result.
[Image via Inhabitat]