One of the dreams of experts in technology and biomimetics has been to imitate the skin of the octopus or squid because of its ability to change color, allowing people or objects to disappear in the environment. And although we were not far from this, making flexible screens for large areas remained prohibitive because a very precise and multi-layered construction was necessary.
Now this has changed thanks to an advance made by a team of scientists led by Jeremy J. Baumberg. These are the smallest pixels ever created, a million times smaller than those on the screen of mobile phones. These mini-pixels could be used for new large-scale flexible screens: large enough to cover entire buildings.
The pixels developed by the Baumberg team are, according to the study published in Science Advances, compatible with the manufacture of flexible plastic films or sheets, which drastically reduces their production cost.
The study authors developed the pixels by coating small grains of gold (one thousand millionths of a meter in diameter) with an active polymer called polyaniline. This thin layer changes chemically when stimulated by electricity, which causes the pixel to change color, but not to just one, but to anyone within the spectrum.
They can be seen in sunlight and, because they do not need a constant power to maintain their established color, they have an energy efficiency that makes their use on large surfaces feasible and sustainable.
“These are not the normal tools of nanotechnology,” Baumberg explains in a statement. “But this kind of radical approach is necessary to make sustainable technologies feasible. The strange physics of light at the nanometric level allows the color to change, even if less than one tenth of the film is covered with our active pixels. This is because, for light, the apparent size of each pixel is many times larger than its physical area.”
These nano pixels could allow a lot of new applications, such as building-sized display screens, architecture that can turn off solar heat load, active camouflage clothing and coatings, or small indicators for the next Internet of things devices.