Big Blue boffins hatch dirt-cheap solar cells
'Earth abundant' materials
IBM researchers have developed a new class of solar-powered electricity-generating cells that they claim will bring photovoltaic cells closer to cost parity with conventional energy sources.
The researchers from IBM's T. J. Watson Research Center in Yorktown Heights, New York have published their findings in a paper entitled "High-Efficiency Solar Cell with Earth-Abundant Liquid-Processed Absorber," available here (PDF).
The materials used in the new cell are copper, zinc, tin, selenium, and sulfur - the latter two "earth-abundant" materials being in a chalcogenide compound, key to the photovoltaic properties of the cell.
The use of these materials bypasses problems inherent in the more-common components of solar cells. The heavy metal cadmium, for example, has toxicity complications, and indium and tellurium (also a chalcogen) are rare and therefore unable to support, as the paper says, more than "a small fraction of our growing energy needs, which are expected to double to 27TW by 2050."
Another advantage of the new cell is that it's manufactured using a simple, non-vacuum process based on what the researchers call a "slurry-based coating method" that allows the photovoltaic layer to be applied by printing, spraying, spin-coating, or other liquid-based techniques.
The efficiency of the new experimental cell is currently at 9.6 per cent, which approaches that of most commerically available solar cells today. IBM's research, however, is still at an early stage, and the new "earth-abundant" cells may very well match or surpass current - relatively expensive - cells and do so at a lower cost and with higher availability. ®
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