Friday, January 9, 2015

New Graphene Compound Could “Revolutionise” Clean Tech

The beauty of GraphExeter is the combination of the new and exotic — graphene — with a widely used, commercially available material. Also called iron chloride, ferric chloride is a common industrial material used for copper etching, sewage treatment, and water purification among other things.

The Next Step For Clean Tech, Via Graphene

So, here’s where things get interesting. It’s been two years since the development of GraphExeter was announced, and the folks over at Exeter haven’t been cooling their heels since then.

Apparently the team was not initially aware that GraphExeter was particularly durable, partly because ferric chloride has a tendency to melt at room temperature. Also it dissolves easily in water, which is a problem.

In other words, you can’t use ferric chloride all by itself, because it falls apart when exposed to air and weather.

When the team started putting GraphExeter through some stress tests, they found that graphene provides the stability that ferric chloride lacks. The results showed that their new graphene compound could even beat out indium tin oxide (ITO), which is commonly used as a conductive material in solar cells, LEDs, and other clean tech applications.

Specifically, they found that GraphExeter could hold up under high humidity, to the tune of 100 percent at room temperature, for 25 days.

They also found that it could withstand temperatures of up to 150 degrees Celsius (that’s 302 degrees Fahrenheit for those of you in the US).

In a vacuum, GraphExeter showed even better results, performing at up to 620 degrees Celsius (1,148 degrees Fahrenheit).

The figure below shows the results of subjecting a GraphExeter sample to heat at room temperature and up. The white scale bar corresponds to five nanometers (a nanometer is one billionth of a meter):

graphene cousin GraphExeter
Results of GraphExeter stress test (courtesy of University of Exeter).
Here’s lead researcher Dr. Monica Craciun enthusing over the results:

By demonstrating its stability to being exposed to both high temperatures and humidity, we have shown that it is a practical and realistic alternative to ITO. This is particularly exciting for the solar panel industry, where the ability to withstand all weathers is crucial.

New Used For Graphene-Enhanced Materials

Did we mention that GraphExeter is transparent? We didn’t? We must have skipped that part in the press materials, but we looked up the study online and we finally put two and two together.

ITO (indium tin oxide) is a transparent material, which makes it ideal for solar cells, LEDs, “smart” windows, and display electronics, but it has a couple of limitations, one major one being its brittleness.

If you can find something to sub in for ITO that’s flexible as well as transparent, and can at least equal ITO in efficiency and cost, then you’re talking transformation.

If you’re interested, the results of the study have just been published at Nature, in the journal Scientific Reports, under the title “Unforeseen high temperature and humidity stability of FeCl3 intercalated few layer graphene.”

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