Flexible Nanoribbons of Crystalline Phosphorus are a World First – They could Revolutionize Electronics and Fast-Charging Battery Technology.


Phosphorous Nanoribbons 5cadc15c710a9
Credit: University College London

Tiny, individual, flexible ribbons of crystalline phosphorus have been made by UCL researchers in a world first, and they could revolutionise electronics and fast-charging battery technology.

Since the isolation of 2-dimensional phosphorene, which is the phosphorus equivalent of graphene, in 2014, more than 100  have predicted that new and exciting properties could emerge by producing narrow ‘ribbons’ of this material. These properties could be extremely valuable to a range of industries.

In a study published today in Nature, researchers from UCL, the University of Bristol, Virginia Commonwealth and University and École Polytechnique Fédérale de Lausanne, describe how they formed quantities of high-quality ribbons of phosphorene from crystals of black phosphorous and lithium ions.

“It’s the first time that individual phosphorene nanoribbons have been made. Exciting properties have been predicted and applications where phosphorene nanoribbons could play a transformative role are very wide-reaching,” said study author, Dr. Chris Howard (UCL Physics & Astronomy).

The ribbons form with a typical height of one , widths of 4-50 nm and are up to 75 μm long. This  is comparable to that of the cables spanning the Golden Gate Bridge’s two towers.

“By using advanced imaging methods, we’ve characterised the ribbons in great detail finding they are extremely flat, crystalline and unusually flexible. Most are only a single-layer of atoms thick but where the ribbon is formed of more than one layer of phosphorene, we have found seamless steps between 1-2-3-4 layers where the ribbon splits. This has not been seen before and each layer should have distinct electronic properties,” explained first author, Mitch Watts (UCL Physics & Astronomy).

While nanoribbons have been made from several materials such as graphene, the phosphorene nanoribbons produced here have a greater range of widths, heights, lengths and aspect ratios. Moreover, they can be produced at scale in a liquid that could then be used to apply them in volume at low cost for applications.

The team say that the predicted application areas include batteries, solar cells, thermoelectric devices for converting waste heat to electricity, photocatalysis, nanoelectronics and in quantum computing. What’s more, the emergence of exotic effects including novel magnetism, spin density waves and topological states have also been predicted.

Wonder material—individual 2-D phosphorene nanoribbons made for the first time

Credit: University College London

The nanoribbons are formed by mixing black phosphorus with lithium ions dissolved in  at -50 degrees C. After twenty-four hours, the ammonia is removed and replaced with an organic solvent which makes a solution of nanoribbons of mixed sizes.

“We were trying to make sheets of  so were very surprised to discover we’d made ribbons. For nanoribbons to have well defined properties, their widths must be uniform along their entire length, and we found this was exactly the case for our ribbons,” said Dr. Howard.

“At the same time as discovering the ribbons, our own tools for characterising their morphologies were rapidly evolving. The high-speed atomic force microscope that we built at the University of Bristol has the unique capabilities to map the nanoscale features of the ribbons over their macroscopic lengths,” explained co-author Dr. Loren Picco (VCU Physics).

Wonder material—individual 2-D phosphorene nanoribbons made for the first time

Credit: University College London

“We could also assess the range of lengths, widths and thicknesses produced in great detail by imaging many hundreds of ribbons over large areas.”

While continuing to study the fundamental properties of the nanoribbons, the team intends to also explore their use in energy storage, electronic transport and thermoelectric devices through new global collaborations and by working with expert teams across UCL.


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Rice University: Graphene-Nano Ribbons Composite Could Keep Wings/ Helo Blades/ Transmission Lines Ice-Free


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Rice University scientists embedded graphene nanoribbon-infused epoxy in a section of helicopter blade to test its ability to remove ice through Joule heating. Credit: Tour Group/Rice University 

A thin coating of graphene nanoribbons in epoxy developed at Rice University has proven effective at melting ice on a helicopter blade.

The coating by the Rice lab of chemist Dr. James M. Tour may be an effective real-time de-icer for aircraft, , transmission lines and other surfaces exposed to winter weather, according to a new paper in the American Chemical Society journal ACS Applied Materials and Interfaces.

In tests, the lab melted centimeter-thick ice from a static helicopter rotor blade in a minus-4-degree Fahrenheit environment. When a small voltage was applied, the coating delivered electrothermal heat – called Joule heating – to the surface, which melted the ice.

The nanoribbons produced commercially by unzipping nanotubes, a process also invented at Rice, are highly conductive. Rather than trying to produce large sheets of expensive graphene, the lab determined years ago that nanoribbons in composites would interconnect and conduct electricity across the material with much lower loadings than traditionally needed.

Previous experiments showed how the nanoribbons in films could be used to de-ice radar domes and even glass, since the films can be transparent to the eye.

Graphene composite may keep wings ice-free
 (L-Click to Enlarge Image)

Lab tests at Rice University on a section of a helicopter rotor chilled to minus-4 degrees Fahrenheit show that a thin coat of nanoribbon-infused epoxy can be used as a de-icer. The composite, imbedded between an abrasion shield and the …more

 

“Applying this composite to wings could save time and money at airports where the glycol-based chemicals now used to de-ice aircraft are also an environmental concern,” Tour said.

In Rice’s lab tests, nanoribbons were no more than 5 percent of the composite. The researchers led by Rice graduate student Abdul-Rahman Raji spread a thin coat of the composite on a segment of rotor blade supplied by a helicopter manufacturer; they then replaced the thermally conductive nickel abrasion sleeve used as a leading edge on . They were able to heat the composite to more than 200 degrees Fahrenheit.

For wings or blades in motion, the thin layer of water that forms first between the heated composite and the surface should be enough to loosen ice and allow it to fall off without having to melt completely, Tour said.

The lab reported that the remained robust in temperatures up to nearly 600 degrees Fahrenheit.

As a bonus, Tour said, the coating may also help protect aircraft from lightning strikes and provide an extra layer of electromagnetic shielding.

Explore further: Researchers create sub-10-nanometer graphene nanoribbon patterns

More information: Abdul-Rahman O. Raji et al. Composites of Graphene Nanoribbon Stacks and Epoxy for Joule Heating and Deicing of Surfaces, ACS Applied Materials & Interfaces (2016). DOI: 10.1021/acsami.5b11131