World Half Full
Solar cells reach highest efficiency ever
Three records have been broken by two different solar cells, including one that pushes solar conversion efficiency to the highest ever at just over 47%.
That honour went to researchers at the US National Renewable Energy Laboratory (NREL), which published its results in Nature Energy. The cells comprise six different types of photoactive layer, which collect energy from different parts of the light spectrum. In total, there are around 140 layers packed into a solar cell that’s thinner than a human hair.
While the record was broken under light focused about 143 times stronger than natural sunlight — meaning the efficiency would obviously be lower in real-world applications — the team says the device could be built with a mirror to focus sunlight onto the cell. They also tested a variation of the cell under light equivalent to one Sun, and it still achieved an efficiency record of 39.2%. That’s equal to or better than coal, gas or nuclear.
Elsewhere, researchers from Germany’s Helmholtz Zentrum Berlin (HZB) broke a different efficiency record, this time for a new type of tandem solar cell, achieving a peak efficiency of 24.16%. The thickness, or rather, thinness, of this technology means flexible solar modules could be produced, which, being extremely light, would be well suited to a wide variety of applications, including in space.
While these are the world’s most efficient solar cells to date, that claim may not last long. These records have a tendency to be broken quite regularly.
ABOVE NREL researchers John Geisz (left) and Ryan France with the solar cell that broke the efficiency record
PHOTO Dennis Schroeder, NREL