Researchers at Oxford University developed a phase-change based display. These materials, the same materials used to make some rewrite-able DVD discs, may enable ultra-low-power (non-volatile) full-color displays with a much faster refresh rate compared to E Ink displays.
The researcher use small jolt of power to change the crystal structure of the material, which changes the way light bends when it hit it, and so it changes the color of the material. Light reflects of each of the layers in different ways, canceling some wavelengths and amplifying others—green and blue light might be eliminated, leaving red, for example. Varying the thickness of the layers, or the voltage applied to the phase change material, affects what colors each pixel in a display shows.
This research is still at an early stage - currently they used an atomic force microscope to 'manually write' images on phase-change material, they didn't yet fabricate a real display that can display an image.