Tag Archives: nanomaterials

Graphene nanoribbons can be transformed into carbon nanotubes by twisting. Photo: Pekka Koskinen

Scientists discover novel way of making carbon nanotubes

A team of researchers comprised of scientists at the NanoScience Center of the University of Jyväskylä, Finland, and at Harvard University, US, have shown through computer simulations a novel technique for generation nanomaterials. The whole process revolves around the extremely simple idea of twisting narrow graphene nanoribbons until they become rolled up into carbon nanotubes, which are 20 times stronger than steel and offer a diverse array of high-tech application – truly one of the most marvelous materials developed by scientists in the past few decades.

The mechanism is trivial, indeed – twisting a ribbon until it becomes a tube. You can check it out for yourself simply by twisting the end strap of your backpack and see what happens. Being a classical mechanism, it renders the same effect both in the macro- and micro-scale. The mechanism also enables experimental control, which has earlier been impossible.

Graphene nanoribbons can be transformed into carbon nanotubes by twisting. Photo: Pekka Koskinen

Graphene nanoribbons can be transformed into carbon nanotubes by twisting. Photo: Pekka Koskinen

Since their development more than twenty years ago, carbon nanotubes have been described as “rolled-up graphenes”, even though there wasn’t any rolling implied in the manufacturing process. Currently, they’re made by atom-by-atom growth, just like most other nanomaterials available today.

The new technique can be use to make various kinds of novel carbon nanotubes, to encapsulate molecules insides the tubes, or to make tubules from ribbons made out of other planar nanomaterials, opening a new realm of manufacturing possibilities, one that could lead to more affordable nanomaterials.

The results were published in Physical Review B. The research was funded by the Finish Academy.

 

Smallest Storage Device in the World to Revolutionize Computing Developed

Miniaturization seems to be the buzzword of the 21st century in this global village.

Thanks to the genius of German and American scientists who have pioneered a revolutionary technique that could be used to develop a new class of hard disk drives with nanomaterials which could store larger amounts of information in a tiny space and at the same time consume lesser energy in computing.

“It could take a few more years before the technique leads to new consumer goods. But once perfected, this method could lead to new types of nanomaterials able to store large amounts of information in tiny spaces, and to consume less energy while doing it,” the researchers claimed.

The researchers in Hamburg and California have built the smallest magnetic storage device in the world, signaling a potential breakthrough for computing.

In a paper published Thursday in the journal ‘Science’, researchers from the Institute of Applied Physics at the University of Hamburg in Germany and an IBM research lab in California demonstrated how they could store a bit, the smallest possible piece of digital information, in a set of 12 atoms.

Normally a bit, either a one or zero, in computer terminology, would require about one million atoms in one of today’s smallest silicon-based storage devices. However, In the new technique, only two rows of six iron atoms on a surface of copper nitride are needed.

“We have built up atom-by-atom data storage,” said Andreas Heinrich, manager of the IBM laboratories in Almaden, California, in an interview with Germany’s Deutsche Welle.

Deutsche Welle is Germany’s international broadcaster that produces television, radio and online content in 30 languages. It provides a European perspective to its global audience and promotes intercultural dialogue.

Instead of using normal Ferromagnets made of iron, nickel or cobalt, the new method relies on anti-ferromagnets, which repel those same elements, granting them various magnetic orientations.

Traditionally, the ferromagnetic approach creates a magnetic field which limits how small a device can be shrunk.

But without the presence of this field, the sets of atoms can be configured in any way without such interference, explained Sebastian Loth, a physicist at the Max Planck Department for Structural Dynamics in Hamburg and a researcher at the IBM research lab in California.

“This new memory principle has the potential to revolutionize the computer technology,” he said.

The new result has already impressed other physicists.

“Current magnetic memory architectures are fundamentally limited in how small they can go,” said Will Branford, a physicist at Imperial College London, in an interview with the BBC.

“This work shows that, in principle, data can be stored much more densely using antiferromagnetic bits.”

However, the researchers note that this is just a very early step in creating smaller memory chips.

For the moment, this 12-atom array is only stable at a temperate of -268 degrees Celsius, near absolute zero. Loth said that at the moment the method would need a setup of about 150-200 atoms per bit of information to make it work at room temperature.

“It’s as if we’ve opened a new door into the next room,” Heinrich added. //EOM//

 

World’s smallest battery created with a nanowire

A team led by Sandia National Laboratories researcher Jianyu Huang created the smallest battery in the world, with a single nanowire 7000 times thinner than a human hair as an anode. The battery was formed inside a transmission electron microscope (TEM) at the Center for Integrated Nanotechnologies (CINT) to allow researchers to better understand the anode’s characteristics.

“This experiment enables us to study the charging and discharging of a battery in real time and at atomic scale resolution, thus enlarging our understanding of the fundamental mechanisms by which batteries work.”, says Huang.

Nanowire technology used in lithium based batteries could offer significant improvements in power and energy density, ultimately leading to a whole new generation of hybrids, laptops, mobile phones, etc.

“What motivated our work,” says Huang, “is that lithium ion batteries [LIB] have very important applications, but the low energy and power densities of current LIBs cannot meet the demand. To improve performance, we wanted to understand LIBs from the bottom up, and we thought in-situ TEM could bring new insights to the problem.”

Battery research groups often use nanomaterials as anodes, but they use them in bulk rather than individually, a process elegantly defined by Huang as “looking at a forest and trying to understand the behavior of an individual tree”. The nanobattery created by the researchers practically consists of a tin oxide nanowire anode 100 nanometers thick and 10 micrometers long a bulk lithium cobalt oxide cathode three millimeters long, and an ionic liquid electrolyte; it’s pretty much the most basic battery you can build. The work can also be conducted with other kind of materials for anode or cathode studies.

“The methodology that we developed should stimulate extensive real-time studies of the microscopic processes in batteries and lead to a more complete understanding of the mechanisms governing battery performance and reliability,” he said. “Our experiments also lay a foundation for in-situ studies of electrochemical reactions, and will have broad impact in energy storage, corrosion, electrodeposition and general chemical synthesis research field.”