A NEW kind of colour e-paper can present bright, high-resolution, full-colour images and video while using minimal energy, pointing to a possible future for display devices.
While traditional LED screens emit red, green and blue light to produce images, e-paper screens use tiny molecules. Until recently, these devices were limited to black and white, but colour screens are now available. Still, they struggle to refresh fast enough to display video.
To address this, Kunli Xiong at the University of Uppsala, Sweden, and his colleagues have developed e-paper with pixels made from tungsten oxide nanodiscs (Nature, doi.org/qbdk). Each pixel is around 560 nanometres across, giving the paper a resolution of 25,000 pixels per inch (PPI). By contrast, smartphones typically have a PPI in the hundreds.
The tungsten-oxide nanodiscs are made with…