A research team at Osaka University has just created a combination of a 'high transparent paper' (nanocellulose, 90% visible light transmission) and a traditional 'white paper' supported by cellulose pulp. Highly transparent electrodes and white electrolyte with high visibility, and the production of paper-based electrochromic (EC) displays. The principle of electrochromic devices is that when a voltage is applied to an EC electrode, ions or electrons enter The EC layer (ionic solution) in the electrolyte shows the characteristic of dyeing or discoloration.
(Research picture 1: Osaka University has developed a new 'paper' electrolyte)
The known problem of conventional battery discoloration devices is that (1) In order to prevent leakage of the electrolyte, sealing must be done, but the production of the thin film is very difficult; (2) With the evaporation of the electrolyte, EC performance will also have The attenuation.
The good news is that the research team led by Hirotaka Koga has succeeded in creating a new type of paper electrolyte supporting non-volatile electrolytes on the surface of paper cellulose through hydrogen bonds.
Its name is 1-butyl-3-methylimidazolium-4-fluoroborate ionic liquid compound (BF4) and it is evenly coated with electricity on the entire surface of transparent paper made of nanocellulose. Color-changing conductive polymer (PEDOT:PSS)
(Study Diagram 2: Comparison of Traditional Electrochromic Displays with New Paper EC Solutions)
Through a sandwich-like sandwich structure, the team developed an EC paper device. This electrochromic solution not only solves the previously mentioned problems, but also possesses the flexibility and flexibility of the paper.
In addition, a white paper electrolyte with a high optical emission coefficient also improves the visibility of the EC display. The research team stated that it can take into account traditional writing media and electro-display properties.
(Study Diagram 3: Functional molecules play an important role in the development of high performance composites)
Combined with other paper-based electronic devices successfully developed, such as memory, transistors, antennas, and super capacitors, we can create a new type of 'paper electronic books'.
