One of promising candidates for the next generation display devices is electronic paper (e-paper), a smart and convenience alternative to traditional paper, has already been used for many applications, one prominent example being the Amazon Kindle e-reader. This technology only requires power when generating and refreshing display content, as it is designed to memorize the content even after the device is turned off.
E-papers have already been commercialized for black-and-white displays, but color e-papers have been unprecedented so far because of the lack of fundamentals. Now, Takuzo Aida, Yoshimitsu Itoh and co-workers at University of Tokyo, RIKEN Center for Emergent Matter Science, and Tokyo Institute of Technology (all in Japan), report the first promising strategy to realize liquid-crystalline displays that are capable of memorizing structural colors even after the applied voltage is switched off. The presented method makes use of “electrophoretic deposition” of a tailored ionic chiral dopant that allows for memorization as well as modulation of the reflection colors of liquid crystals. This research could contribute greatly to sustainable electronics, because displays in principle are the most equipped and the most energy-demanding component in electronic devices in our daily life.