IBM researchers set sights on cooler CPV technology

As part of wider plan to leverage advanced research at IBM to significantly reduce the cost-per-watt of solar photovoltaics from silicon cells, thin-film and concentrator photovoltaics (CPV), IBM scientists are developing a more powerful CPV technology that they claim could lead to a significant breakthrough for utility-scale applications.

A paper presented by IBM at the IEEE Photovoltaic Specialists conference last week highlighted an innovative cooling technique to keep solar cells operating at high efficiency levels. The IBM team used a very thin layer of a liquid metal made of a gallium and indium compound that they applied between the chip and a thermal interface layer.

The result was a solar cell operating at a controlled 85 degrees Celsius, significantly less than a typical CPV device. The researchers noted that without the thermal interface layer the temperatures would reach 1600 degrees.

“We believe IBM can bring unique skills from our vast experience in semiconductors and nanotechnology to the important field of alternative energy research,” said Dr. Supratik Guha, the scientist leading photovoltaics activities at IBM Research. “This is one of many exploratory research projects incubating in our labs where we can drive big change for an entire industry while advancing the basic underlying science of solar cell technology."

With the development of the liquid metal cooling technology, IBM is developing a concentrator lens that is more powerful and lower in cost than conventional CPV lens technologies to achieve lower cost-per-watt systems.

Currently, IBM claims to have produced 70 watts of usable electrical power from a typical solar cell, which they claim is about five times the electrical power density generated by typical cells using CPV technology in solar farms.

IBM lab results are claimed to have produced a 2300 sun system, where approximately 230 watts per square centimeter are concentrated onto the cell system. This cuts the number of photovoltaic cells and other components by a factor of 10, according to IBM.

Further development work is being carried out before the cooling and lens technology can be commercialized.