A biodegradable electrochromic display that reduces e-waste

A team at the Karlsruhe Institute of Technology has developed an experimental electronic display that can be composted when no longer needed

Spotted: Each year, the total amount of electronic equipment society uses grows by 2.5 million tonnes. As most of this equipment cannot be reused or recycled, this is constantly adding to the world’s growing mountain of e-waste. In 2019, 53.6 million tonnes of e-waste was generated globally and by 2030, it is likely to increase to 74.7 million tonnes. In an effort to minimise this problem, a team of scientists at Germany’s Karlsruhe Institute of Technology (KIT) have developed an experimental electronic display that can be composted when no longer needed. It is likely that this technology will be most applicable in short-lifecycle applications, such as disposable skin-worn sensors that monitor patients’ conditions, or food packaging that indicates when it has gone off.

The electrochromic display utilises an organic polymer known as PEDOT:PSS, which changes the amount of light absorbed, according to the amount of voltage that is applied. As a result, segments of the display will change between clear and opaque states. To produce the device, the polymer is deposited on a cellulose di-acetate substrate and sealed in an electrolyte gelatine, making it both flexible and adhesive, after which the electrical current is applied via gold electrodes. The production process is an inexpensive one as the displays can be produced using an inkjet printer, which can easily be scaled up for commercial production.

According to the researchers, this is the first demonstration of a biodegradable display produced by inkjet print, and they hope it will pave the way for sustainable innovations in other electronic components and also increase the production of eco-friendlier electronics.

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