Display technologies are at the heart of the technology revolution that has swept the world over the past decades. From dagguereotypes and celluloid through to LCDs and electrophoretic displays, the requirement to exchange and manipulate information conveniently has demanded continual progress towards lightweight, robust, colour displays with low power consumption and every higher brightness, resolution, and refresh-rate. Increasingly there is a demand for flexible or semi-transparent displays, and daylight-readable displays that do not require backlighting.
Now the group of Harish Bhaskaran at the University of Oxford of introduced a new technology that promises to deliver on many of these fronts. In a recent letter published in Nature, they demonstrate the use of ultra-thin phase change materials - which alter their crystal structure in response to heat - to create high resolution, fast, flexible and semi-transparent colour displays. The researchers used nm-thick layers of germanium antimony tellurium alloy (GST) to dynamically control the optical path length within a dielectric stack, enabling electrically-controlled colour changes. The very thin materials could be controlled rapidly and with very low power consumption, which could enable e-readers to display video. The layers were also thin enough that they could be bent, enabling flexible displays.