Where is the future of electronics? on the tree
Wood-derived nanocellulose paper semiconductors made
Science and Technology Daily, Beijing, May 4 (Reporter Zhang Mengran) Japanese researchers have developed a nanocellulose paper semiconductor that exhibits nano-micro-macro cross-scale designability of 3D structures and extensive tunability of electrical properties.
The findings were recently published in ACS Nano, a core journal of the American Chemical Society.
Semiconductor nanomaterials with 3D network structures possess high surface areas and a large number of pores, making them ideal for applications involving adsorption, separation, and sensing.
However, it remains challenging to simultaneously control electrical properties, create useful micro- and macro-structures, and achieve excellent functionality and end-use versatility.
Cellulose is a natural and readily available material derived from wood.
Cellulose nanofibers (nanocellulose) can be made into sheets of flexible nanocellulose paper (nanopaper) with dimensions similar to standard A4 paper.
Nanopaper does not conduct electricity, but heating can introduce conductive properties.
However, this heating can also damage the nanostructures.
In collaboration with the University of Tokyo, Kyushu University and Okayama University, Osaka University researchers have devised a treatment process that enables nanopaper to be heated without damaging the paper structure from the nanoscale to the macroscale.
"An important property of nanopaper semiconductors is tunability, as this allows design for specific applications." Study author Associate Professor Koga Hirono explained that the iodine treatment was very effective in protecting the nanostructure of the nanopaper.
Combining this with spatially controlled drying means that the pyrolysis treatment does not significantly alter the structure of the design, and selected temperatures can be used to control electrical properties.
The researchers used origami and kirigami techniques to provide the flexibility of nanopaper at the macroscopic level.
They folded birds and boxes, stamped out shapes like apples and snowflakes, and laser-cut them to create more complex structures.
This is a testament to the level of detail possible with the new process, and that the heat treatment did not cause damage.
Examples of successful applications are nanopaper semiconductor sensors incorporated into wearable devices to detect moisture exhaled through masks and moisture on the skin.
Nanopaper semiconductors are also used as electrodes in glucose biofuel cells, producing energy that lights up a small light bulb.
The structural maintenance and tunability demonstrated by the new study to turn nanomaterials into actual devices is very encouraging, and the new method lays the foundation for the next step in sustainable electronics made entirely from plant materials, says Koga Boron.
[Editor-in-chief's circle]
Nano has magical magic.
When everything goes down to the micro level, things change, cellulose is a natural material, make nanocellulose into paper and you have a prototype for sustainable electronics.
How to make this nanopaper have electrical properties?
The answer is heating.
Researchers in Japan have used iodine treatment to allow nanopaper to maintain its micro and macro structure after being heated, and the nanopaper can also produce different electrical conductivity depending on the temperature.
Researchers have initially applied it to wearable devices.
Although the functions are not particularly complete, it would be cool to have an electronic product from nature in the future.