Nav: Home

Graphene substrate improves the conductivity of carbon nanotube network

October 09, 2019

Transparent conductive films (TCFs) have many applications in touch screens, organic light emitting diodes and solar cells. These applications need materials that are strong, energy efficient and stable, which is why companies and researchers are interested in carbon-based materials. This applies especially to networks of single-walled carbon nanotubes, which are expected to replace the metal-oxide films that are currently used.

Graphene is the thinnest imaginable material, it is just one atomic layer of carbon atoms. Rolling this into a cylinder makes a carbon nanotube, which is better suited to carrying electricity in real-world applications. In an article published in ACS Nano, scientists at Aalto University and the University of Vienna introduce a hybrid material made by combining carbon nanotubes and graphene, which improves the conductivity of the film beyond what is possible when using each of these component structures separately.

Professor Kauppinen's group at Aalto has years of experience in making carbon nanotubes for TCFs. This new work applies the techniques they have developed to place densely-packed and clean random nanotube networks on graphene. "This is another application of the technologies we have developed over the past decades. Put simply, this work is about how the two materials are put together without solvents," Kauppinen explains.

In the study, the scientists used a process called thermophoresis to deposit nanotubes on prefabricated graphene electrodes. The hybrid films' conductivities were roughly twice as high as predicted.

The experiments conducted by the team at the University of Vienna, led by Jani Kotakoski, showed that the strong electrical interactions of graphene enhanced the flow of electrons between the nanotubes by encouraging charge-tunneling. The team used a scanning transmission electron microscope to look at the material on the scale of individual atoms, and saw that the van der Waals interaction between the graphene and nanotubes was strong enough to collapse the circular nanotube bundles into flat ribbons.

The lead scientist from the Vienna group, Kimmo Mustonen, explains: "This is really an ingenious approach. The charge transport in nanomaterials is very sensitive to any external factors. What you really want is to avoid unnecessary processing steps if your goal is to make the ideal conductive film." Mustonen adds, "It actually is quite remarkable. We of course knew that the interaction is quite strong. For instance, think of graphite; it is just a large number of graphene layers bound together by the same mechanism. Yet we did not expect that it has such a strong impact on conductivity."

The results provide opportunities to improve the conductivity of similar hybrid nanomaterials. The article was published in "ACS Nano" in September 2019.

Aalto University

Related Graphene Articles:

How to stack graphene up to four layers
IBS research team reports a novel method to grow multi-layered, single-crystalline graphene with a selected stacking order in a wafer scale.
Graphene-Adsorbate van der Waals bonding memory inspires 'smart' graphene sensors
Electric field modulation of the graphene-adsorbate interaction induces unique van der Waals (vdW) bonding which were previously assumed to be randomized by thermal energy after the electric field is turned off.
Graphene: It is all about the toppings
The way graphene interacts with other materials depends on how these materials are brought into contact with the graphene.
Discovery of graphene switch
Researchers at Japan Advanced Institute of Science and Technology (JAIST) successfully developed the special in-situ transmission electron microscope technique to measure the current-voltage curve of graphene nanoribbon (GNR) with observing the edge structure and found that the electrical conductance of narrow GNRs with a zigzag edge structure abruptly increased above the critical bias voltage, indicating that which they are expected to be applied to switching devices, which are the smallest in the world.
New 'brick' for nanotechnology: Graphene Nanomesh
Researchers at Japan advanced institute of science and technology (JAIST) successfully fabricated suspended graphene nanomesh (GNM) by using the focused helium ion beam technology.
Flatter graphene, faster electrons
Scientists from the Swiss Nanoscience Institute and the Department of Physics at the University of Basel developed a technique to flatten corrugations in graphene layers.
Graphene Flagship publishes handbook of graphene manufacturing
The EU-funded research project Graphene Flagship has published a comprehensive guide explaining how to produce and process graphene and related materials (GRMs).
How to induce magnetism in graphene
Graphene, a two-dimensional structure made of carbon, is a material with excellent mechani-cal, electronic and optical properties.
Graphene: The more you bend it, the softer it gets
New research by engineers at the University of Illinois combines atomic-scale experimentation with computer modeling to determine how much energy it takes to bend multilayer graphene -- a question that has eluded scientists since graphene was first isolated.
How do you know it's perfect graphene?
Scientists at the US Department of Energy's Ames Laboratory have discovered an indicator that reliably demonstrates a sample's high quality, and it was one that was hiding in plain sight for decades.
More Graphene News and Graphene Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: IRL Online
Original broadcast date: March 20, 2020. Our online lives are now entirely interwoven with our real lives. But the laws that govern real life don't apply online. This hour, TED speakers explore rules to navigate this vast virtual space.
Now Playing: Science for the People

#574 State of the Heart
This week we focus on heart disease, heart failure, what blood pressure is and why it's bad when it's high. Host Rachelle Saunders talks with physician, clinical researcher, and writer Haider Warraich about his book "State of the Heart: Exploring the History, Science, and Future of Cardiac Disease" and the ails of our hearts.
Now Playing: Radiolab

There are so many ways to fall–in love, asleep, even flat on your face. This hour, Radiolab dives into stories of great falls.  We jump into a black hole, take a trip over Niagara Falls, upend some myths about falling cats, and plunge into our favorite songs about falling. Support Radiolab by becoming a member today at