[Image above] Credit: Diego Correa; Flickr CC BY 2.0


1202ctt jackie chan

The always-smiling Jackie Chan. Credit: Gage Skidmore; Wikimedia Commons

Jackie Chan must be smiling somewhere. (Then again, when isn’t Jackie Chan smiling?)

Chan’s 1992 film “Police Story 3: Super Cop” may be forgotten by many, but, thanks to the work of Northwestern University researchers, will long be remembered for its hand in improving solar cell efficiency.

Published in Nature Communications, their findings suggest that Blu-ray discs are not only a boost to one’s Saturday evening plans, but also to how solar cells can absorb light.

How, you ask?

According to a Northwestern news release, the secret is the supersecret patterns written on discs such as Super Cop.

“We had a hunch that Blu-ray discs might work for improving solar cells, and, to our delight, we found the existing patterns are already very good,” says Jiaxing Huang, author, materials chemist and an associate professor of materials science and engineering. “It’s as if electrical engineers and computer scientists developing the Blu-ray technology have been subconsciously doing our jobs, too.”

Unlike the technology of yesteryear—DVDs, CDs—Blu-ray discs boast data that is far more dense.

When applied to the solar cells’ surface, this “quasi-random pattern” of binary code 0s and 1s is just the “near-optimal surface texture” solar cells need for making light absorption more efficient—racking up an overall absorption of 21.8%. 

To demonstrate the efficiency, Huang and coauthor Cheng Sun, associate professor of mechanical engineering, used Super Cop as a blueprint for duplicating the Blu-ray pattern on a polymer solar cell. They found that the cell was “more efficient than a control solar cell with a random pattern on its surface.”

Though Chan’s Blu-ray was the first to be tested, it really doesn’t matter what content is on the disc. That means that whether you’re into action, rom-coms, or thrillers—and whether they’re in color or classics in black and white—your media cabinet contains discs that can enhance absorption and performance equally well.

“We found a random pattern or texture does work better than no pattern, but a Blu-ray disc pattern is best of all,” says Huang.

Sun says that the work holds application not just for polymer cells. “In addition to improving polymer solar cells, our simulation suggests the Blu-ray patterns could be broadly applied for light trapping in other kinds of solar cells,” he says.

“It has been quite unexpected and truly thrilling to see new science coming out of the intersection of information theory, nanophotonics, and materials science,” adds Huang.

Two cheers—and roundhouse kicks—for science!

The paper, also written by Alexander J. Smith, Chen Wang, and Dongning Guo, is “Repurposing Blu-ray Movie Discs as Quasi-random Nanoimprinting Templates for Photon Management” (DOI:10.1038/ncomms6517).