Biodegradable displays enable eco-friendly electronics

Scientists from the Karlsruhe Institute of Technology (KIT) have produced electronic displays whose biodegradability has been checked and certified by an independent office. Their research, published in the Journal of Materials Chemistry C, points to a future where electronic devices can have a more sustainable life cycle, rather than being dumped as e-waste.

“For the first time, we have demonstrated that it is possible to produce sustainable displays that are largely based on natural materials with the help of industrially relevant production methods,” said first author Manuel Pietsch, a researcher at KIT’s Light Technology Institute (LTI) who is based at the Heidelberg InnovationLab.

“After use, these displays are no electronic scrap, but can be composted. In combination with recycling and reuse, this might help minimise or completely prevent some of the environmental impacts of electronic scrap.”

Functioning of the display is based on the so-called electrochromic effect of the initial organic material. When voltage is applied, light absorption is modified and the material changes its colour. Electrochromic displays have a low energy consumption and simple component architecture compared to commercially available displays, such as LED, LCD and e-paper.

Another advantage is that these displays can be produced by inkjet printing in a customised, inexpensive and material-efficient way. Moreover, this process is suited to scaling with a high throughput. The materials used are mainly of natural origin or biocompatible, and sealing with gelatine makes the display adhesive and flexible, such that it can be worn directly on the skin.

The display is generally suitable for short-lifecycle applications in various sectors. In medical diagnostics, for instance, where hygiene plays an important role, sensors and their indicators have to be cleaned or disposed of after use. The newly developed display will not be dumped as e-waste as it is compostable. It can also be used for quality monitoring in food packaging, where reuse is not permitted. Digital printing allows the displays to be adapted to different people or complex shapes without any expensive modification of the process, reducing the consumption of resources.

“As far as we know, this is the first demonstration of a biodegradable display produced by inkjet printing,” said Gerardo Hernandez-Sosa, Head of LTI’s Printed Electronics Group at the InnovationLab. “It will pave the way to sustainable innovations for other electronic components and to the production of eco-friendlier electronics.”

Image caption: Thanks to its flexibility and adhesion, the biodegradable display can be worn directly on the hand. Image credit: Manuel Pietsch, KIT.

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