Experimental Solar Cell Sets Efficiency Record
A photovoltaic device with a solar cell that converts 40.8 percent of light that hits it into electricity has set a world record and become the highest confirmed efficiency of any photovoltaic device to date.
A photovoltaic device with a solar cell that converts 40.8 percent of light that hits it into electricity has set a world record and become the highest confirmed efficiency of any photovoltaic device to date.
The inverted metamorphic triple-junction solar cell was designed, fabricated and independently measured at the U.S. Department of Energy's National Renewable Energy Laboratory (NREL).
The 40.8 percent efficiency was measured under concentrated light of 326 suns. One sun is about the amount of light that typically hits Earth on a sunny day. The new cell is a natural candidate for the space satellite market and for terrestrial concentrated photovoltaic arrays, which use lenses or mirrors to focus sunlight onto the solar cells.
The new solar cell differs significantly from the previous record holder, NREL says. Instead of using a germanium wafer as the bottom junction of the device, the new design uses compositions of gallium indium phosphide and gallium indium arsenide to split the solar spectrum into three equal parts that are absorbed by each of the cell's three junctions for higher potential efficiencies.
This is accomplished by growing the solar cell on a gallium arsenide wafer, flipping it over, then removing the wafer. The resulting device is extremely thin and light and represents a new class of solar cells with advantages in performance, design, operation and cost, according to NREL.
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