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World’s ‘greenest green’ could make ultra high-definition displays even sharper

Not all greens are created equal. There’s lime green, mint green, British racing green. And now there’s practically pure green, thanks to chemical engineers at ETH Zurich, who have created the world’s greenest green. They say it will improve color quality in the ultra high-definition displays of the future.

“To date, no one has succeeded in producing green light as pure as we have,” Chih-Jen Shih, a chemical engineering professor who co-created the light-emitting diode in his lab, said in a statement.

The screens of today’s ultra high-def (UHD) TVs, computers, and smartphones are a sight to behold, and yet there’s still room for improvement. But, in order to make that progress, researchers first have to develop pure red, blue, and green light, which will be able to display images in unparalleled detail and with more nuanced color ranges. Pure red and blue have been achieved, according to the researchers, but green remained elusive until now.

This is because the human eye is able to pick up more green hues than we can with red and blue.

“This makes the technical production of ultra-pure green very complex, which creates challenges for us when it comes to developing technology and materials,” said Sudhir Kumar, who helped Shih create the light in his lab.

The purity of Shih and Kumar’s green can be grasped by comparing it to the technical standards, known as Rec. 2020. The purest TV displays currently available don’t exceed 80 percent, and average between 73.11 and 77.72. The ETH Zurich green falls within the 97 and 99 range.

But Shih and his team’s efforts didn’t stop there. They also created an ultra-thin, bendable light-emitting diode that can emit this pure green light at room temperature, whereas previous LED technology required high temperatures to generate the pure light.

“Because we were able to realize the entire process at room temperature, we’ve opened up opportunities for the simple, low-cost industrial production of ultra-green light-emitting diodes in the future,” said co-creator Jakub Jagielski.

As with most breakthroughs, there’s a bit of a catch — the LED converts electricity to light at just three percent efficiency, compared to commercial TV screen, which work at five to ten percent. That means he and his team will have to focus on making their technology more efficient before it’s ready for commercial application.

A paper detailing the research was published in the journal Nano Letters.

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