Physics group uses graphene to allow electron microscopy of liquid objects

April 6, 2012 by Bob Yirka report
Image(c) Alivisatos, Lee and Zettl research groups, LBNL.

( -- News of new uses for graphene continue to come in with remarkable regularity, and now a team of physicists, as they describe in their paper published in the journal Science, have figured out a way to use it to create a sandwich that can be used to study objects under an electron microscope that are immersed in liquid.

Up till now, studying so-called objects using an has been more than a little tricky. This is because such require specimens to be held in a vacuum while being dosed with electrons. Unfortunately, tend to vaporize when put into a vacuum, making them pretty hard to study. Up to now, researchers have been forced to use less than optimal substances to hold the materials in place, such as . Unfortunately, because such materials tend to be rather thick, the images created using them haven’t been of very high quality.

This shows TEM images of platinum nanocrystal coalescence and their faceting in the growth solution. Credit: KAIST

Graphene, as most know by now, is a single sheet of carbon atoms, highly touted for its unusual electrical properties, its transparency and of course it’s strength. It’s the second property that got this research team interested. They wondered what would happen if graphene was used to trap a liquid when placed in vacuum and then under an electron microscope. Because it’s just one atom thick, they figured, it should allow for the creation of much higher quality images than they’d managed with other materials.

To find out, they created a sealed sandwich made up of two layers of graphene, covering a layer of platinum ions in a liquid solution. They wanted to see if they could actually watch platinum nanocrystals being formed, which would go a long ways towards understanding how the whole process works. They then placed the sandwich into the electron microscope vacuum to see how things progressed.

To sum up, it worked quite well. The group reports that they were able to watch the nanocrystals grow with remarkable clarity and don’t see any reason why the same approach wouldn’t work for other wet chemistry samples, which would open up the use of electron microscopy to a whole new area of science, namely, biochemistry.

There is the problem of how biological specimens react to being bombarded with , essentially radiation, however. Thus far, no one really knows if the graphene will provide any protection for the material being studied, but this team is anxious to find out. No doubt once they do, another paper will be forthcoming describing those results as well.

Explore further: An easy way to see the world's thinnest material

More information: High-Resolution EM of Colloidal Nanocrystal Growth Using Graphene Liquid Cells, Science 6 April 2012: Vol. 336 no. 6077 pp. 61-64. DOI: 10.1126/science.1217654

We introduce a new type of liquid cell for in situ transmission electron microscopy (TEM) based on entrapment of a liquid film between layers of graphene. The graphene liquid cell facilitates atomic-level resolution imaging while sustaining the most realistic liquid conditions achievable under electron-beam radiation. We employ this cell to explore the mechanism of colloidal platinum nanocrystal growth. Direct atomic-resolution imaging allows us to visualize critical steps in the process, including site-selective coalescence, structural reshaping after coalescence, and surface faceting.

Related Stories

An easy way to see the world's thinnest material

December 23, 2009

It's been used to dye the Chicago River green on St. Patrick's Day. It's been used to find latent blood stains at crime scenes. And now researchers at Northwestern University have used it to examine the thinnest material ...

Bilayer graphene is another step toward graphene electronics

August 11, 2011

The Nobel Prize winning scientists Professor Andre Geim and Professor Kostya Novoselov have taken a huge step forward in studying the wonder material graphene and revealing its exciting electronic properties for future electronic ...

Recommended for you

Physicists develop new technique to fathom 'smart' materials

November 26, 2015

Physicists from the FOM Foundation and Leiden University have found a way to better understand the properties of manmade 'smart' materials. Their method reveals how stacked layers in such a material work together to bring ...

Mathematicians identify limits to heat flow at the nanoscale

November 24, 2015

How much heat can two bodies exchange without touching? For over a century, scientists have been able to answer this question for virtually any pair of objects in the macroscopic world, from the rate at which a campfire can ...

New sensor sends electronic signal when estrogen is detected

November 24, 2015

Estrogen is a tiny molecule, but it can have big effects on humans and other animals. Estrogen is one of the main hormones that regulates the female reproductive system - it can be monitored to track human fertility and is ...


Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Apr 06, 2012
One day I'm going to marry Graphene, make me a sammich.
not rated yet Apr 06, 2012
Graphene is a great toy and a huge job generator for contemporary physicists. If it wouldn't exist, they should invent it. But the practical applications of it are still much more modest.
not rated yet Apr 12, 2012
If the graphene layer is then provided with an array of sensors and circuitry to read it out you could directly readout the activities nearby without a vacuum or electron beam. Though maybe you would need bigraphene with an intact layer to protect the active electronics from the liquid.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.