Have you ever imagined that you can pick an electronic component from a tree just like a fruit? If the work of Osaka University researchers can yield results, we will indeed be able to ‘grow on trees’ electronic hardware components in the future.
Universities of Tokyo and Kyushu, together with Okayama University, have developed a semiconductor nanocellulose paper in which 3D structures can be designed on a nano-micro-macro scale and electrical properties can be adjusted. So what does this mean?
‘In the future we will grow electronic parts on trees’
Cellulose is a natural and easily obtained material derived from wood. Cellulose nanofibers (nanocellulose) can be produced in sheets of flexible nanocellulose paper (nanopaper) with dimensions similar to those of standard A4. In fact, nanopapers do not conduct electric current, but it is possible to gain conductive properties with heat treatment. Unfortunately, exposure to heat can also damage the nanostructure.
Therefore, Okayama University researchers have developed a heat treatment process that allows them to heat nanopaper from nanoscale to macroscale without damaging the paper’s structures. Hirotaka Koga, spokesperson and author of the study, says:
“An important property of nanopaper semiconductor is that it is tunable because it allows devices to be designed for specific applications. An iodine process that is very effective for preserving the nanostructure of nanopaper. Combining this with spatially controlled drying meant that the pyrolysis process did not significantly disrupt the designed structures and the chosen temperature could be used to control the electrical properties.”
Researchers used origami (paper folding) and kirigami (paper cutting) techniques to provide examples of nanopaper flexibility at the macro level. The experiment used materials such as a folded paper bird and box, a paper cut apple, and a snowflake. This showed what could be the level of detail possible, as well as minimizing the damage caused by heat treatment.
The produced semiconductor nanopaper was used as an electrode in a glucose biofuel cell, and the energy produced lit a small light bulb. “The structure and tunability we’ve been able to demonstrate is a beacon for transforming nanomaterials into practical devices. We believe our work is an important step toward being able to produce electronic hardware made entirely from plant materials,” says Koga, research spokesperson. Although we will not actually be able to collect electronics from wood, it may be possible for us to use devices made entirely of plant materials.
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