Scientists has been attempting for years to develop a technology that mimics the color changing skin of an octopus or a squid allowing it to blend into the natural background. Just recently, a team of scientists made a breakthrough discovery. There had been several similar attempts to develop the technology but the cost has always been a major hurdle for all of them, until now.
Led by the University of Cambridge, a team developed the smallest pixels yet created - a million times smaller than those being used in smartphones. This is the basic unit that makes up a large-area flexible display screen that would allow the long-coveted color-changing ability.
The members of the team came from a variety of fields, including physics, chemistry, and manufacturing. Initially, they coated vats of golden grains with an active polymer called polyaniline and sprayed them onto flexible mirror-coated plastic. This was what drove the cost of production down dramatically.
"We started by washing them over aluminized food packets, but then found aerosol spraying is faster," said co-lead author Hyeon-Ho Jeong from Cambridge's Cavendish Laboratory.
A tiny particle of gold a few billionths of a meter across lies at the center of the pixels. It sits on top of a reflective surface and is surrounded by a thin sticky coating which changes chemically when electrically switched, which would cause the pixel to change color across the spectrum. The pixels can be seen in bright sunlight and since they do not need constant power to keep their color they then have an energy performance that makes large areas feasible and sustainable.
"These are not the normal tools of nanotechnology, but this sort of radical approach is needed to make sustainable technologies feasible," said Professor Jeremy J Baumberg of the NanoPhotonics Centre at Cambridge's Cavendish Laboratory, who led 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."
Applications for the said technology is boundless. It ranges from creating building-sized display screens, building architecture which can switch off solar heat load, creating active camouflage clothing and coatings, to creating tiny indicators for coming internet-of-things devices.
The research itself was funded as part of a UK Engineering and Physical Sciences Research Council (EPSRC) investment in the Cambridge NanoPhotonics Centre, as well as the European Research Council (ERC) and the China Scholarship Council.
