Wood transistor using balsa wood
Van Tinh Trang
Electrical switches made of conductive wood could be building blocks for future electronic devices embedded in living trees and other plants.
“There is a new field of research called electronic plants, where scientists are looking at different ways to send signals inside plants or to integrate functions such as sensors into plants and living plants.” says Isak Engquist of Linköping University in Sweden.
Engquist and his colleagues developed the wood equivalent of a transistor. This is an electronic component that can amplify current or act as a switch for electrical signals. A single computer chip the size of a fingernail contains billions of tiny transistors. It is made of a semiconductor material such as silicon. Each semiconductor transistor can be switched on and off billions of times per second. Compared to silicon transistors, Wood transistors are quite large, each 3 cm long. It also has a very slow switching speed and can be switched off in about 1 second and switched on in about 5 seconds.
However, wood transistors may prove more sustainable and biocompatible for certain electronic applications in agriculture and forestry, such as monitoring plant resistance to environmental stress and climate change. I have.
To create the wood transistor, Engquist and his colleagues used heating and chemical processes to remove lignin, an organic binding substance in wood and plants, from balsa wood. This process freed up spaces within and between the natural network of tubes called lumina that carry water within the wood.
The wood was then soaked in a liquid solution containing a conductive polymer, allowing the polymer to penetrate the wood and coat it with lumina. This created a conductive wood that could interact with electrolytes (chemicals that conduct electricity when dissolved in water) and was used as the basis for building wood transistors.
Researchers have demonstrated and measured the behavior of the Wood transistor during multiple switching test runs. This represents “exciting engineering possibilities for utilizing wood” as scaffolding “where electronic materials can be incorporated into devices,” said Tian Li, of Purdue University in Indiana. increase. He was not involved in this research.
The team initially tried several types of wood, including birch and ash. However, balsa wood offers ideal properties for this approach, such as maintaining structural integrity after lignin removal, absorbing conductive polymers without problems, and no significant seasonal differences between summer and winter wood. It turned out that I have
Researchers may eventually grow conductive wood with the polymer already inside, says Enquist. This could involve using various conductive polymers to impregnate the wood without first removing the lignin.
“Each piece of wood, or each plant, most likely contains just a few wood electrochemical transistors, and these would be on the millimeter-size scale,” says Engquist.
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