In the coming years, the increasing use of electronic devices in everyday objects and new technologies in connection with the Internet of Things threaten to increase the production of electronic waste. More environmentally friendly production and a more sustainable life cycle are crucial here in order to save resources and minimize waste. Scientists at the Karlsruhe Institute of Technology (KIT) have succeeded for the first time in producing displays whose biodegradability has been independently tested and confirmed. Their results have been published in the "Journal of Materials Chemistry".

"With our development, we were able to show for the first time that it is possible to produce sustainable displays from predominantly natural materials using industrially relevant production methods. They therefore do not contribute to electronic waste after use, but on the contrary can be composted. In combination with recycling and reusability, this could help to minimize or completely prevent some of the environmental impacts of electronic waste," says Manuel Pietsch, first author of the publication and researcher at KIT's Light Technology Institute (LTI) at the InnovationLab in Heidelberg, describing the advantages of the new development.

Low energy consumption, simple component architecture

The function of the display is based on the so-called electrochromic effect of the organic base material used. If a voltage is applied to it, this leads to a change in the absorption of light and thus to a color change in the material. Electrochromic displays are characterized by low energy consumption and a simple component architecture compared to commercially available displays such as LEDs, LCDs and e-paper. Another advantage is that these displays can be produced using the inkjet printing process, enabling customized, cost-effective and material-efficient production. This process is also suitable for scaling processes with high throughput. The materials used are mainly of natural origin or biocompatible. Sealing with gelatine also makes the display adhesive and adaptable, allowing it to be worn directly on the skin on various parts of the body.

Indicator for sensors or simple displays

The display is generally suitable for short-lived applications as an indicator for sensors or simple displays in various areas. Particularly in diagnostic applications, where hygiene plays an important role, the sensors and their indicators have to be laboriously cleaned or disposed of after each use. In the case of the newly developed display, this does not result in electronic waste, but can simply be composted. The display could also be used as a compact display for quality-monitoring sensors in the area of food packaging, which must not be reused. The digital printing process also enables individual adaptation to people or complicated shapes without expensive process redesign, which again saves resources.

"The first demonstration of an inkjet-printed, biodegradable display, as far as we know, can therefore encourage sustainable innovations in other electronic components and thus pave the way for more environmentally friendly electronics," says Gerardo Hernandez-Sosa, Head of the Printed Electronics Group of the LTI at the InnovationLab in Heidelberg.

Original publication:
Manuel Pietsch, Stefan Schlisske, Martin Held, Noah Strobel, Alexander Wieczorek, Gerardo Hernandez-Sosa: Biodegradable inkjet-printed electrochromic display for sustainable short-lifecycle electronics. Journal of Materials Chemistry, DOI: 10.1039/d0tc04627b