This news is a week old, but I just saw it. A team at Princeton has developed a new kind of solar cell and dramatically increased its efficiency. This new cell uses nanotechnology to be almost 3 times more efficient than the best cells out there today.
Quote:
Chou, the Joseph C. Elgin Professor of Engineering, said the research team used nanotechnology to overcome two primary challenges that cause solar cells to lose energy: light reflecting from the cell, and the inability to fully capture light that enters the cell.
With their new metallic sandwich, the researchers were able to address both problems. The sandwich — called a subwavelength plasmonic cavity — has an extraordinary ability to dampen reflection and trap light. The new technique allowed Chou's team to create a solar cell that only reflects about 4 percent of light and absorbs as much as 96 percent. It demonstrates 52 percent higher efficiency in converting light to electrical energy than a conventional solar cell.
That is for direct sunlight. The structure achieves even more efficiency for light that strikes the solar cell at large angles, which occurs on cloudy days or when the cell is not directly facing the sun. By capturing these angled rays, the new structure boosts efficiency by an additional 81 percent, leading to the 175 percent total increase. Chou said the system is ready for commercial use although, as with any new product, there will be a transition period in moving from the lab to mass production.
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In a nutshell, there is a tiny mesh on the top surface of the cell, and light waves can get through the holes in the mesh, but can't bounce back out because the holes are too small. So they get trapped inside and generate electricity.
The conventional cell reflects a ton of light, but the new cell traps it. These new cells look pitch black and work well even on cloudy days.
Electron microscope view of the mesh on the surface of the cell.
Nanotechnology sounds expensive to manufacture, but solar cells are already expensive to manufacture, so maybe these new cells can compete on price too. I hope so.