The highest efficiency for a solar panel has been achieved by Alta Devices, the California-based solar company proudly announced on Monday.
The efficiency rating of 23.5 percent, meaning that the panels are able to convert 23.5 percent of energy captured from the sun into electrical output, was verified by the National Renewable Energy Laboratory (NREL).
“This is the highest solar panel efficiency yet achieved and demonstrates Alta’s progress toward its objective of developing solar photovoltaic (PV) solutions that are competitive, without subsidies, with fossil fuels,” the company wrote in a press release.
Toward that end, Alta Device’s highest-efficiency panel was created based on an innovative, even counter-intuitive idea about how to maximize energy conversion: The panels themselves emit fluorescent light, as TPM reported in November 2011, when the research was in its earlier stages.
The idea makes sense when one considers that conventional polysilicon solar panels and cells lose energy as heat, reducing their efficiency. But when Alta’s panels lose any energy, it’s in the form of external fluorescence, which is less detrimental to the conversion process.
Back in November 2011, Alta’s panels had managed to hit an astounding 28.4-percent efficiency, approaching the maximum 33.5 percent Shockley-Queisser efficiency limit, though that was just for an individual solar cell. The full panel itself contains several cells, decreasing its efficiency slightly.
The panels themselves are made of gallium arsenide (GaAs), a byproduct of aluminum smelting combined with arsenic, a combination that is ideal for solar cell production due to the fact that it can withstand high temperatures and yet be cut extremely flexible and extremely thin, one micron thick in the case of Alta’s panels. That’s about 1/40th the thickness of a human hair, according to the company, allowing it to be used for a variety of applications, where conventional polysilicon panels can’t go.
Alta Devices itself is the result of solar technology research breakthroughs achieved at the University of California Berkeley. The company was founded in 2007 and has received venture capital funding. It plans to produce its panels for commercial use later this year.