Blu-ray discs have become largely obsolete in the arena of digital downloads and streaming video. But they are now gearing up for a new and completely different return. It turns out that, the blue-bottomed discs are very good at enhancing the light-absorbing properties of solar panels.
The tiny patterns etched into the bottom of the discs are perfect for collecting and scattering light onto the energy absorption technologies of modern solar panels. While the actual Blu-ray discs cannot be used in the panels because of their light-blocking opacity, their pattern is simply borrowed and replicated on the panel.
The researchers also found that quasi-random patterns are perfect pattern templates for semi-random arrangements of microscopic grooves, ideal for capturing and dispersing light as it hits the surface of a solar panel. But producing such a pattern is rather expensive.
"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 press release. "It's as if electrical engineers and computer scientists developing the Blu-ray technology have been subconsciously doing our jobs, too."
Huang and his colleagues at Northwestern University first made impressions of the bottoms of the Blu-ray discs. They used these impressions to create copied patterns by pressing them into a thin coat of liquid plastic. Finally, the transparent plastic sheets were then placed on solar panels, and the light-absorbance was found to increase by almost 22 percent than any regular panels. The researchers said it was quite a surprise that the experiment worked so well.
The researchers experimented on a vast array of old discs containing various movies and TV shows including action films, dramas, cartoons and documentaries. They found that the content of the discs was irrelevant, they all performed equally well in their light absorption job. Huang and his colleagues concluded the blu-ray discs proved superior due to the algorithms used in their encoding process. These algorithms turn the data such as movies, music etc into quasi-random textured patterns that proved well-suited for capturing light over the whole solar spectrum.
The Blu-ray discs are much superior to DVDs in their data storage abilities. They compress a lot of information onto such a tiny surface using data processing algorithms that translate video signals into a sequence of zeros and ones. While seemingly random, the sequence actually has a bit of redundancy built in, limiting too many consecutive zeros or ones.
"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 added.