The most advanced LED screens look amazing compared to what was on the market even a couple of years ago. But a Princeton engineer found a cheap new way of making LEDs not only brighter and more efficient but also five times as clear. It even makes them last longer.
Professor Stephen Chou is renowned for his 2012 nanotechnology breakthrough that increased solar cell efficiency by 175 per cent. Now, he’s applied the same principle to LED technology. “From a view point of physics, a good light absorber, which we had for the solar cells, should also be a good light radiator,” said Chou in a press release. “We wanted to experimentally demonstrate this is true in visible light range, and then use it to solve the key challenges in LEDs and displays.”
That key challenge is one that scientists have been struggling with since the invention of the LED. While the technology is extremely energy efficient, only 2- to 4-per cent of the light generated by an LED is actually emitted. The rest becomes trapped in the LED casing, the same way that light gets trapped underwater in a swimming pool.
Chou’s nanotechnology changes the equation. It uses nanostructure called a plasmonic cavity with subwavelength hole-array (PlaCSH) to direct and focus light towards the viewer. It’s basically just a wire mesh created out of wire that’s just 15 nanometers thick. The light-emitting surface below that then shines through brighter, and since less light is trapped less heat is generated, extending the lifespan of the LED.
Thanks to a method that Chou himself invented, it’s very cheap to manufacture organic and inorganic LEDs with a PlaCSH technology. He and Princeton are just waiting on their patent applications to go through, and then you might start seeing this stuff pop up in smartphones. You might just have to wait a few years, too. [IEEE Spectrum]