A transistor made of wood: Sign of a future revolution in materials?

It may be bulky but the first wood transistor works. Image: Courtesy of Linköping University / Thor Balkhed

The first ever transistor made of wood, capable of regulating an electrical flow, has been developed in a laboratory in Sweden. More ecological than traditional transistors, it opens the door to other developments while a practical use case has yet to be established.

Researchers at Linköping University, in association with the Royal Institute of Technology, Stockholm (KTH) have succeeded in developing the world's first wooden transistor. A transistor is a basic electronic component, usually made of pure silicon, which controls or amplifies electrical voltages and currents. They are found in all electronic devices, sometimes on microscopic scales. The challenge here was to make the wood capable of conducting electricity.

To achieve this technological feat, the researchers used balsa, a grainless wood with an even structure. They extracted the lignin from it, thus accentuating the presence of cellulose fibers. They then filled the empty channels with a conductive polymer or plastic (PEDOT:PSS) so that the wood block itself would become electrically conductive.

In the end, this first-ever wooden transistor is "slow" and "bulky," the researchers admitted. But the main accomplishment is that it functions, that it is able to regulate electricity flow without deteriorating. Therefore it can serve as a basis for other exciting future developments.

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Indeed, there are numerous advantages to this type of wooden transistor. Compared to silicon, wood is a sustainable and renewable material, which means that it's a much more environmentally friendly solution. Secondly, the large transistor channel could be suitable for regulating electric plants. However the researchers took care to point out that they "didn't create it with any specific application in mind," rather it falls into the category of "basic research," showing that something is possible.

The research is published in an article in the journal PNAS.