The schematic schematics for the making of wood electrochemical transistors (B) and conductive wood preparation (A). (C) Front view shot of a WECT, front view of the WECT arrangement, and zoomed-in segment of a wood fiber (conceptual image of transistor’s channel) displaying the electrolyte-transporting lumen and PEDOT:PSS-coated cell wall. Acknowledgment: National Academy of Sciences Proceedings (2023). DOI: 10.1073/pnas.2218380,00020
Swedish engineers and organic chemists from Linköping University and KTH Royal Institute of Technology have shown that treated wood may be used to create functional transistors. The findings have been released in the National Academy of Sciences Proceedings.
Electronics called transistors are used in bigger electronics to either switch or amplify electrical impulses. Over time, scientists have developed techniques to reduce their size to the point where billions of them can fit on a single computer chip. The majority of transistors can only be used with specific materials; transistors on chips, for instance, are based on silicon, a semiconducting material. In its latest endeavor, the Swedish researchers investigated the potential for developing transistors for use in bioelectronic goods or perhaps solely plant-based electronics. They built a transistor out of wood and a few other materials to test the theory.
After testing several tree species, the team concluded that balsa’s strength, permeability, and low density made it the best choice for their purposes. To make the wood more porous, they first soaked thin strips of it in a chemical solution to extract some of its lignin. Then, scientists pushed a conductive material known as PEDOT:PSS, which coated the vessel walls, into the tiny wooden vessels that are typically used for water transportation.
Three slats of the treated wood were all that were required; two of the wide ones were used as control electrodes, and they were set atop one another. The third, which acted as a conduit between the power supply and the current drain, was positioned perpendicularly between the two wider slabs. To enable the passage of ions and electrons, the scientists additionally filled the channel’s voids with an electrolyte gel. Furthermore, a cellulose-based thin cloth was used to divide the strips. A transistor with a cross shape was the end product.
By using 2.5 volts of current to test their gadget, the team discovered that the flow could be stopped as intended. The group admits that, in comparison to other devices in use, theirs is slow—it takes about one second to switch off the current and five seconds to switch it back on—but they suggest it shows that construction of bio-transistors is possible.