Photovoltaic cell performance of 35.8% for Sharp

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Photovoltaic cell performance of 35.8% for Sharp
It isn't our custom to publish news off the usual beaten path of Folding@Home and computer tech, but today we'll make an exception. We now turn our attention to solar cells and other renewable energies.

The Japanese company Sharp has announced that it has developed a photovoltaic cell with a performance rating of 35.8%. This is a new world record in performance, without the use of concentrated solar rays.

This is a triple junction cell: it consists of 3 layers of semiconductor to increase the absorption potential; each layer being capable of absorbing a wavelength of its own. Most cells of this type use a layer of gallium phosphide, indium (InGaP), an intermediate layer of gallium arsenide, indium (InGaAs) and a lower layer of germanium (Ge).

Although germanium layers are very simple to fabricate, half of the electricity that appears in this layer cannot be used, and thus loses currents. Researchers at Sharp have therefore come up with the idea of replacing the material of the gallium-arsenide-indium with a much more effective combination. The new cell is composed of a layer of gallium phosphide, indium (InGaP), an intermediate layer of gallium arsenide (GaAs) and a lower layer of gallium arsenide, indium (InGaAs). The performance of this cell reached 38.5%, compared with other cells that have capped at 31.5%. This efficiency can be increased to 45% by using a concentrated light magnification of 1000.

Other features of the cell are:

  • Open circuit voltage (Voc): 3012 V
  • Short-circuit current (Isc): 12.27 mA
  • Form Factor (F.F.): 85.3%
  • Area: 1 cm²

These cells will be used initially in satellites by 2012. We are still far from the kind of returns from other energy sources, but progress is very real, and we hope to eventually yield enough solar energy to fully power our machines... and maybe even more besides.

Source: Bulletins Electroniques