To produce
energy from sunlight, light can be converted directly via a photovoltaic cell,
or the sun's heat can be used to boil water to drive turbines
producing energy.
But a third way could be developed. This would be a more direct one. It would avoid us the constraints of the first method, with which the conversion can be done with certain frequencies of light. It would also avoid us a complicated process that results from the water boiling technique.
Researchers at the Massachusetts Institute of Technology (MIT) have developed a kind of trap to direct sun; the device consists of a thin layer of tungsten (a very resistant metal). A surface of this layer is facing the sun, and is covered with microscopic traps. The other surface is facing a special type of solar cell and is carved in a structure called a photonic crystal. This crystal allows the structure to emit infrared radiation at a frequency with which they are best absorbed by the solar cell. These two surfaces are created by photolithography which is the same process that allows the manufacture of computer chips.
The tiny traps on the first layer capture the sun's rays, especially when they are aligned with it. The heated tungsten becomes much warmer than it would otherwise be. To be transformed into energy, the heat is directed to the solar cell through the photonic crystal, whose property is to modify the propagation of electromagnetic waves.
But a third way could be developed. This would be a more direct one. It would avoid us the constraints of the first method, with which the conversion can be done with certain frequencies of light. It would also avoid us a complicated process that results from the water boiling technique.
Researchers at the Massachusetts Institute of Technology (MIT) have developed a kind of trap to direct sun; the device consists of a thin layer of tungsten (a very resistant metal). A surface of this layer is facing the sun, and is covered with microscopic traps. The other surface is facing a special type of solar cell and is carved in a structure called a photonic crystal. This crystal allows the structure to emit infrared radiation at a frequency with which they are best absorbed by the solar cell. These two surfaces are created by photolithography which is the same process that allows the manufacture of computer chips.
The tiny traps on the first layer capture the sun's rays, especially when they are aligned with it. The heated tungsten becomes much warmer than it would otherwise be. To be transformed into energy, the heat is directed to the solar cell through the photonic crystal, whose property is to modify the propagation of electromagnetic waves.
Basma –
Green Energy International Correspondent – 04/01/12
Solar energy has gone from being the great white hope, to an impediment, to a reliable energy supply. Solar farm operators and homeowners with solar panels on their roofs collected more than €8 billion ($10.2 billion) in subsidies in 2011, but the electricity they generated made up only about 3 percent of the total power supply, and that at unpredictable times.
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