The world’s first wooden transistor
(Nanowerk News) Researchers at Linköping University and KTH Royal Institute of Technology have developed the world’s first transistor made of wood. Their study, published in the journal PNAS (Modulation of electric currents in wood electrochemical transistors), paved the way for the further development of wood-based electronics and electronic factory control.
The transistor, invented nearly a hundred years ago, is considered by some to be as important an invention for humanity as the telephone, the light bulb, or the bicycle. Today, they are essential components in modern electronic devices, and are produced on the nanoscale. The transistor regulates the current through it and can also act as a power switch.
Researchers at Linköping University, together with colleagues from the KTH Royal Institute of Technology, have now developed the world’s first electric transistor made of wood.
“We came up with an unprecedented principle. Yes, the wooden transistor is slow and bulky, but it works, and has great development potential, ”says Isak Engquist, senior professor in the Laboratory of Organic Electronics at Linköping University.
In previous trials, transistors made of wood were only able to regulate ion transport. And when the ions run out, the transistor stops working. The transistors developed by the Linköping researchers, however, can function continuously and regulate the flow of electricity without breaking down.
The researchers used balsa wood to make their transistors, because the technology involved requires fiber-free wood to be uniformly structured. They remove the lignin, leaving only long cellulose fibers with channels where the lignin sits.
These channels are then filled with a conductive plastic, or polymer, called PEDOT:PSS, resulting in an electrically conductive wood material.
The researchers used this to build a wooden transistor and were able to show that it is able to regulate amperage and provide a continuous function at a selected output level. It can also turn the power on and off, albeit with a certain delay – turning it off takes about a second; on, about five seconds.
Possible applications could include electronics factory setting, which is another strong area of research at Linköping University. One advantage of such a large transistor channel is that it can potentially tolerate higher currents than typical organic transistors, which may be important for certain future applications. But Isak Engquist has something to emphasize:
“We did not build wooden transistors with any particular application in mind. We do it because we can. This is basic research, demonstrating that it is possible, and we hope it will inspire further research that may lead to future applications,” said Isak Engquist.