Monday, December 4, 2023

Researchers develop the world’s first wood transistor

The nature of mass transport in plants has recently inspired the development of low-cost and sustainable wood-based electronics.

Researchers at Linköping University and the KTH Royal Institute of Technology have developed the world’s first electrical transistor made of wood – a move they claim could pave the way for further development of wood-based electronics and control of electronic plants.

Transistors are considered by some to be an invention just as important to humanity as the telephone, the light bulb, or the bicycle. They are a crucial component in modern electronic devices and are manufactured at the nanoscale.

This is not the first time researchers have attempted to produce wooden transistors, but previous trials resulted in wood transistors that regulate ion transport only. And when the ions run out, the transistor stops functioning. On the other hand, the new transistor developed by the Linköping researchers can function continuously and regulate electricity flow without deteriorating.

As the technology involved requires a grainless wood that is evenly structured throughout, the researchers used balsa wood to create their transistor. They removed lignin from the balsa wood, leaving only long cellulose fibers with channels where lignin had been. The remaining hollow channels were then filled with a conductive plastic polymer, resulting in an electrically conductive wood material.

The components of the wood transistor.
The components of the wood transistor. Credit: Thor Balkhed

The new wood transistor showed it is able to regulate electric current and provide continuous function at a selected output level. It could also switch the power on and off, albeit with a certain delay – activating the device takes around five seconds while deactivating it takes another second.

Despite this, researchers believe the concept has practical applications, including the regulation of electronics plants. Also, it could tolerate a higher current than regular organic transistors, which could be important for future applications.

“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,” says Isak Engquist, senior associate professor at the Laboratory for Organic Electronics at Linköping University. “We didn’t create the wood transistor with any specific application in mind. We did it because we could. This is basic research, showing that it’s possible, and we hope it will inspire further research that can lead to applications in the future.”

Journal reference:

  1. Van Chinh Tran, Gabriella G. Mastantuoni, Marzieh Zabihipour, Lengwan Li, Lars Berglund, Magnus Berggren, Qi Zhou, and Isak Engquist. Electrical current modulation in a wood electrochemical transistor. PNAS, 2023. DOI: 10.1073/pnas.2218380120