Fish scales could provide an eco-friendly alternative to plastic for use in flexible displays for electronic devices.
Flexibility is important for wearable electronics to enable the creation of displays that bend, fold or twist easily, says Hai-Dong Yu at Nanjing Tech University in China. Plastic has been the go-to material for achieving this kind of flexibility but because of its harmful impact on the environment, sustainable, low-cost alternatives are highly sought after.
Fish scales account for 3 per cent of the 70.5 million metric tonnes of fish produced globally each year. They usually don’t get eaten and go to waste, but Yu and his team saw potential in flexible electronics.
The team extracted gelatin from fish scales and used this to create an extremely thin film. Tiny silver nanowires were then incorporated into it, to act as electrodes, along with a light-emitting material made of zinc sulphide and copper, to provide light for the electronic display.
The result was a flexible electronic display, which fully biodegraded after 24 days in soil. A plastic display can takes centuries to break down. This means fish-scale films could also be useful for creating disposable wearable electronic devices, says Yu.
“We are excited about boosting the development of green flexible electronics, which may drive a paradigm shift in our daily life,” he says.
Yu says that, in addition to biodegradability, the fish-scale films have the advantages of high transparency, low surface roughness and low cost. They can also be recycled by dissolving them in warm water.
Dipankar Mandal at the Institute of Nano Science and Technology in Mohali, India, says we can expect to see more “bio-electronics” like this in the near future. Alongside fish scales, other biological materials are being explored for similar purposes, including cellulose from cotton fibres and silk protein from silk worms.