Thin-film solar companies may not like questions about their conversion efficiency, but two new studies out this week from MIT and UCLA could eventually help solar cell manufacturers achieve numbers worth bragging about.
In a study published in this week’s Journal of the American Chemical Society, UCLA researchers developed a new plastic that could be an important step in creating more flexible and affordable solar cells. Plastic and polymer solar cells are not new (the lead researcher on today’s study came out earlier this year with a method for producing semi-transparent versions of the cells), but their efficiency has for years been less than impressive.
The new technology from UCLA, which could make solar installations possible on more varied surfaces, isn’t breaking efficiency record. While about 5.1 percent of the light hitting UCLA’s new cell gets converted to energy, the global leader in thin-film technology, First Solar, reports efficiency of more than twice that.
The MIT team used computer modeling to design thin-film crystalline silicon cells that, according to the researchers, are up to 50 percent more efficient than today’s commercial offerings. They have an antireflective coating on the front, and layers of reflective coatings, plus tightly-spaced lines called diffraction grating, on the back.
Slated to present the innovation at a conference in Boston next week, the MIT scientists say their design remains far from mass production. But according to researcher Peter Bermel, refining the design (and reducing its cost) could give the team a technology ripe for licensing to companies like CSG Solar and Oerlikon Solar, which work with thin-film solar cells around the same thickness (5 microns) as MIT’s layered cells.