Taking inspiration from squids’ color-changing skin, researchers have created pixels that are a million times smaller than the ones in your phone’s OLED screen. The invention opens the path to awesome practical applications, from giant wallpapers that can change a room’s look in real time to health monitors that you can view on the surface of your own skin.
Published in the journal Science Advances, the research says that this new technology is “highly competitive” with current displays, both OLED and persistent electronic ink ones. The paper claims that the technology can show any color in the visible spectrum, has extremely low power requirements, very high contrast, can be easily seen under direct sunlight, and has a refresh rate of 50Hz. This is not as high as the current 60Hz standards, but is good enough for video and impressive for a persistent display technology.
Called active plasmonic metasurface, this new display technology uses extremely tiny pixels made of single gold nanoparticles. The pixels are laid down using aerosol spraying on a reflective surface rather than employing expensive lithography processes that would make large scale displays prohibitively expensive.
The scientists — working at the NanoPhotonics Centre, the NanoManufacturing Group, and the Bio-inspired Photonics Group at the University of Cambridge — then applied a coating that changes depending on the current, changing the pixels’ color. The pixel can basically show any color you can imagine — and even go into the ultraviolet.
But while the pixel size is tiny, the color area is much larger than the actual size. According to Professor Jeremy J Baumberg, one of the authors of the research, “the strange physics of light on the nanoscale allows it to be switched, even if less than a tenth of the film is coated with our active pixels. That’s because the apparent size of each pixel for light is many times larger than their physical area when using these resonant gold architectures.”
The researchers describe that its unique characteristics make it ideal for real-world applications like color-changing wallpapers, smart windows, traffic management systems, electrical signage, and many types of display panels.
Credit: Science Advances