Still a better fate than VHS: Unwanted Blu-ray discs repurposed for solar power

Engineers find Blu-ray discs at the “intersection of information theory, nanophotonics, and materials science” and copy their microscopic patterns in solar panels to improve light absorbance.

by John Tyburski

Copyright © Daily Digest News, KPR Media, LLC. All rights reserved.

First published at Daily Digest News on November 26, 2014

Blu-ray discs had their day in the sun, but they may be gearing up for a new, completely different return. While video streaming offered by services such as Netflix continue to send Blu-ray sales down the tubes, scientists are casting some new light on these information-packed plastic discs and how they can advance solar technology. Apparently, the blue-bottomed discs are very good at increasing the light-absorbing properties of solar panels.

The feature of the discs that grabbed the interest of solar scientists is the tiny patterns etched into data side. These microscopic patterns are perfect for collecting and scattering photons onto the energy-absorbing materials of modern solar panels. While the actual Blu-ray discs cannot be used in the panels because of their light-blocking opacity, their patterns are replicated in the panels. In other words, they are perfect pattern templates for semi-random arrangements of microscopic grooves, features that are expensive to manufacture otherwise.

“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,” Jiaxing Huang, a materials chemist and solar panel expert at Northwestern University, said in a statement. “It’s as if electrical engineers and computer scientists developing the Blu-ray technology have been subconsciously doing our jobs, too.”

The primary qualities that make Blu-ray discs great templates is that their data patterns are semi-random and densely arranged. To copy the patterns, Huang and his coworkers first made impressions of the bottoms of the Blu-ray discs. They used these impressions to create copied patterns by pressing them into liquid plastic spread in thin coats. These films were then placed on solar panels, and the light-absorbance was found to increase by almost 22 percent.

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