Research Leads to the 3D Printing of Pure Graphene Nanostructures

 Graphene  

Researchers in Korea have successfully 3D printed graphene nano-structures without the use of any other material. With the entire printed structure being composed of graphene, the strength, as well as full conductivity of the material can be taken advantage of.

There is no question that graphene, has enormous potential, from solar cell technology, to electronics to medicine.  A key factor in developing practical and commercial applications of the one-atom thick carbon sheets is in aligning the material in the desired form depending on the application.

Now 3D printing of graphene is nearing a feasible stage and companies such as Graphene 3D Lab, are at the forefront of the technology.

However, there is a difference between 3D printing pure graphene, and 3D printing a graphene/thermoplastic composites like Graphene 3D has been doing.

While printing with composite materials, using a typical FDM/FFF or powder based laser sintering process, will keep some of graphene’s superior properties intact, most will be lost. The plastic will eventually break down leaving any prints weak, and not much different from a typical object you’d print with a MakerBot Replicator.

Now, researchers, led by Professor Seung Kwon Seol from Korea Electrotechnology Research Institute (KERI), recently published a paper in Advanced Materials where they describe a new process of directly 3D printing pure graphene.

Their techniques mean that graphene nano-structures can be fabricated without the use of any other material. With the entire printed structure being composed of graphene, the strength, as well as full conductivity of the material can be realized.

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"We developed a nanoscale 3D printing approach that exploits a size-controllable liquid meniscus to fabricate 3D reduced graphene oxide (rGO) nanowires," Seol told Nanowerk. "Different from typical 3D printing approaches which use filaments or powders as printing materials, our method uses the stretched liquid meniscus of ink. This enables us to realize finer printed structures than a nozzle aperture, resulting in the manufacturing of nanostructures."

"We are convinced that this approach will present a new paradigm for implementing 3D patterns in printed electronics."

“So far, to the best of our knowledge, nobody has reported 3D printed nanostructures composed entirely of graphene,” says Seol. “Several results reported the 3D printing (millimeter- or centimeter-scale) of graphene or carbon nanotube/plastic composite materials by using a conventional 3D printer. In such composite system, the graphene (or CNT) plays an important role for improving the properties of plastic materials currently used in 3D printers. However, the plastic materials used for producing the composite structures deteriorate the intrinsic properties of graphene (or CNT).”

"We are convinced that this approach will present a new paradigm for implementing 3D patterns in printed electronics," says Seol.

For their technique, the team grew graphene oxide (GO) wires at room temperature using the meniscus formed at the tip of a micropipette filled with a colloidal dispersion of GO sheets, then reduced it by thermal or chemical treatment (with hydrazine).

The deposition of GO was obtained by pulling the micropipette as the solvent rapidly evaporated, thus enabling the growth of GO wires. The researchers were able to accurately control the radius of the rGO wires by tuning the pulling rate of the pipette; they managed to reach a minimum value of ca. 150 nm.

Using this technique, they were able to produce arrays of different freestanding rGO architectures, grown directly at chosen sites and in different directions: straight wires, bridges, suspended junctions, and woven structures.

Seol points out that this 3D nanoprinting approach can be used for manufacturing 2D patterns and 3D geometry in diverse devices such as printed circuit boards, transistors, light emitting devices, solar cells, sensors and so on.

A lot of work remains to reduce the 3D printable size to below 10 nm and increase the production yield. A short video of Seol's process is below:



SOURCE  Nanowerk

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