IBM is hoping to use its experience with semiconductors and nanotechnology to reduce the cost of concentrator photovoltaics (CPV) technology for large-scale electricity generation.
The company recently achieved a record of capturing 230 W onto a centimetre square solar cell and is hoping to move the project forward tomanufacturing. The breakthough would bring significant cost advantages if it can overcome some additional challenges, says IBM.
CPV technology involves the use of a large lens to concentrate the sun’s power. It has the potential to offer the lowest cost solar electricity for large-scale power generation provided that the temperature of the cells can be controlled and that cheap and efficienct optics can be developed for concentrating the light to very high levels.
“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.”
IBM’s lab results represent a leap to the development of a 2300 sun system, where one sun is a measurement equal to the solar power incident at noon on a clear summer day. Such concentrations would cut the number of photovoltaic cells and other components required by a factor of ten, compared with a 200 sun system.
But the challenge lies in cooling the solar cells, and IBM says it has borrowed innovations from its research and development into computer chip cooling technology to achieve results.
Concentrating the equivalent of 2000 suns on such a small area generates enough heat to melt stainless steel, but IBM says that it has been able to cool the solar cell from 1600°C to just 85°C. Its research team achieved this by coupling a commercial solar cell to an advanced IBM liquid metal thermal cooling system using methods developed for the microprocessor industry.
Specifically, IBM used a very thin layer of a liquid metal made of a gallium and indium compound and applied it between the chip and a cooling block. Such layers, called thermal interface layers, transfer the heat from the chip to the cooling block so that the chip temperature can be kept low.
IBM is exploring four main areas of photovoltaic research: using current technologies to develop cheaper and more efficient silicon solar cells, developing new solution processed thin film photovoltaic devices, concentrator photovoltaics, and future generation photovoltaic architectures based upon nanostructures such as semiconductor quantum dots and nanowires.
The goal of the projects is to develop efficient photovoltaic structures that would reduce the cost, minimise the complexity, and improve the flexibility of producing solar electric power.
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