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Unlike previous attempts, the transistor developed by researchers at Linköping University and the KTH Royal Institute of Technology, both in Sweden, can reportedly function continuously and regulate electricity flow without deteriorating.
Transistors are crucial components in modern electronic devices, regulating the current that flows through them and functioning as power switches. They are often manufactured at the nanoscale.
In previous trials, the researchers said that transistors made of wood could only regulate ion transport. When the ions ran out, the transistors stopped functioning.
“We’ve come up with an unprecedented principle. Yes, the wood transistor is slow and bulky, but it does work, and has huge development potential,” said Isak Engquist, senior associate professor at the Laboratory for Organic Electronics at Linköping.
The researchers used balsa wood to create their transistor, as the technology requires a grainless wood that is evenly structured throughout. They removed the lignin, leaving only long cellulose fibres with channels where the lignin had been. Those channels were then filled with a conductive polymer called PEDOT:PSS, creating an electrically-conductive wood material.
The team used that to build the wood transistor, showing that it can regulate electric current and provide continuous function at a selected output level. It could also switch power on and off, with a slight delay – switching it off took about a second, while switching it on took about five seconds.
Possible applications could include regulating ‘electronic plants’, which are a strong focus of research at Linköping. Integrating electronics into plants could create ‘biohybrid’ systems, or enable plant monitoring and optimisation.
One advantage of the transistor channel being so large is that it could potentially tolerate a higher current than regular organic transistors, the researchers said.
“We didn’t create the wood transistor with any specific application in mind,” said Engquist. “We did it because we could… we hope it will inspire further research that can lead to applications in the future.”
The study was financially supported by the Knut and Alice Wallenberg Foundation through the Wallenberg Wood Science Centre.
A paper on the work was published in PNAS.
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