The scientific group from Japan managed to create electronic paper from a simple paper. The novel technology is based on the combining of the transparent paper with the clarity about 90%, which is produced from cellulose nanofibers, and a simple paper that is produced from cellulose pulp fibers. As a result, combining a highly transparent electrode and a white electrolyte with high transparency, they managed to create paper-based electrochromic (EC) displays. Furthermore, with the help of this technology, scientists have already made various paper-based electronic devices, for example, memory, supercapacitors, and transistors. They hope this newest development will provide the ability to create paper-based electronic books.
The technology was developed by the scientific team, led by Ph.D. Hirotaka Koga, from the Osaka University.
Functional molecules are the highly important element in the producing of high-performance composite materials. In EC devices, when a voltage is applied to a transparent EC electrode, ions or electrons transfer into the EC layer in the ionic liquid or electrolyte. As the result, the coloration or decoloration happens. Nevertheless, current EC devices have some problems. The sealing was required in order to prevent the outflow of the electrolyte. Consequently, the effectiveness of EC device depends on the evaporation of the electrolyte.
Scientists decided to combine the nonvolatile ionic liquid and an easy-to-handle cellulose paper substrate in order to solve this problem. The paper electrolyte is supported by the non-volatile electrolyte on the surface of cellulose pulp fibers with the help of the hydrogen connections. The photochromic molecule was attenuated in the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide. The produced paper composites demonstrate reversible, rapid, uniform and vivid coloration and bleaching upon ultraviolet and visible light irradiation. Consequently, this innovative EC device has the ability to solve these problems, which were previously mentioned, but it is flexible and easily curve due to its paper-basis. Furthermore, the white paper electrolyte with high optical reflectance increases the visibility of the device.
In additions, with the help of this innovational technique, they have already produced various paper-based electronic devices such as supercapacitors and transistors. This technology will allow researchers to create paper-based electronic books.