Blu-ray Discs get repurposed to improve solar cells

Polymer imprinted with movies' etchings captures more sunlight

Microscope image of a Blu-ray Disc

LIGHT-FETCHING PATTERN  Bumps and pits that encode data on a Blu-ray Disc, seen here in a false-color microscope image, can be imprinted on solar cells to improve light absorption, a new study shows.

Jiaxing Huang

Using Blu-ray Discs to watch movies is so 2006. Now they can boost the efficiency of solar cells. Imprinting the discs’ data-storing etchings onto solar cells increases the cells’ absorption of sunlight, according to a study published November 25 in Nature Communications.

Previous research has shown that making nanometer-sized etchings onto a solar cell’s surface helps trap more light, so Jiaxing Huang, a materials chemist at Northwestern University in Evanston, Ill., looked to Blu-ray Discs, which store data in the form of tiny bumps and pits. He and his team collected various movies and TV shows, and used a mold of the discs to imprint their patterns onto polymer solar cells.

The patterned solar cells that Huang’s team tested absorbed nearly 22 percent more light than smooth cells. By coincidence, Huang says, the manufacturing process to compress data and prevent scratches from ruining discs creates etching patterns that help absorb light.

The results suggest that Blu-ray Discs collecting dust could cheaply improve the performance of many varieties of solar cells. It appears that any mass-produced Blu-ray will do: The PBS documentary The Dust Bowl works just as well as the TV cartoon Family Guy, and a widely panned movie (The Room) fares no worse than Citizen Kane.

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