Golden (CO) - Scientists at the U.S. Department of Energy's (DoE) National Renewable Energy Laboratory (NREL) claim to have set a new world record in solar cell efficiency: A new photovoltaic device can convert 40.8% of the light it is exposed to into electricity – which is more than twice as much as average solar cells can achieve today.
Improving the efficiency of solar cells is a key research area in the photovoltaic segment, as current mas market solar cells are converting less than 20% of sunlight into electricity, but high-end solar cells made by Boeing-Spectrolab and used by the DoE and NASA have been approaching 40%. A new material now allowed the NREL to increase the efficiency by a few more percentage points.
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 new “inverted metamorphic triple-junction solar cell” design proved to be highly effective, hitting an efficiency of 40.8% under concentrated light of 326 suns (326 times the amount of light that hits Earth on a sunny day.)
The NREL said that the solar cell is “extremely thin and light and represents a new class of solar cells with advantages in performance, design, operation and cost.” Just don’t expect this device to become available for the roof of your home or a future Toyota Prius anytime soon: According to the NREL, the solar cell technology will be targeting the space satellite market as well as photovoltaic arrays which are typically sued by solar cell power plants and use lenses or mirrors to focus sunlight onto the solar cells.
It may take some time until consumers will see similarly efficient solar cells. There are research projects that claim to increase solar cell efficiency with relatively simple enhancements above 23% and nano-flakes may improve this value to 30% at some point. For the near future, solar cell efficiency enhancements such as a new technology from National Semiconductor could have an impact on solar cells and further out we hope that nanoantennas may complement solar cells to convert created heat into electricity.