The US Department of Energy’s National Renewable Energy Lab, or NREL, has developed a new solar energy cell with an efficiency level so high that it could outperform classic fossil fuels, according to a recent report. The cell harvests wasted heat to perform better than classic solar cells.
The performance of a solar cell is often measured in external quantum efficiency – a measure of the number of electrons flowing through the cell versus the number of photons entering it. The more electrons flowing, the more energy the cell will produce. This new cell performed at a record efficiency of 114 percent, which could be better than fossil or even nuclear fuels.
The “wasted heat” technology is made possible by quantum dots, which are tiny crystals of a semiconductor rather than the traditional bulk semiconductors. These tiny crystals can harvest excess energy that would normally be lost in the form of heat and use the energy for power. Best of all, quantum dot solar cells would be inexpensive to manufacture and extremely efficient to use in residential and non-residential solar panels.