07/11/11 Baltimore, Maryland – Cheap solar panels. The most powerful transistors ever. Even the ability to make a fighter jet invisible.
One barrier to solar breakthrough – its cost – is going down
Each of these breakthroughs has been announced in the last two weeks. Each relies on one of the most basic elements mined from the earth. And each could line your pockets with cash if you move quickly enough.
They all involve a wonder substance called graphene. It’s made from graphite – the same stuff you find in the center of a pencil. Except graphene consists of a single layer of carbon atoms.
Let’s hopscotch through these new developments…
Researchers in India have discovered how to build solar panels using graphene – a development that could finally make widespread solar energy economical.
Graphene solar panels have several advantages over silicon solar panels – starting with a better ability to absorb light. The problem is that up to now, they’ve been a lot more expensive – because the graphene requires other materials to move the electrons around just right.
The Indian scientists put two and two together. They realized that you can also build solar panels using “quantum dots” – microscopic quantities of particles like cadmium or lead. The problem with that is that cadmium and lead are highly toxic.
So…they wondered…what if they built “graphene quantum dots”?
Graphene quantum dots, seen really close-up. “20 nm” is 20 nanometers – about 1/5,000th the width of a human hair
Here’s what makes the scientists’ findings, published in the Journal of the American Chemical Society, so promising: The graphene quantum dots can transport electrical current more quickly than silicon.
That makes it much more efficient. So instead of waiting 10 years for silicon-based solar panels to “pay for themselves,” you might have to wait only five years or less.
Meanwhile, researchers at MIT have figured out a way to make more graphene more quickly.
Up to now the process has involved – literally – taking sticky tape to a chunk of graphite and flaking it off. The MIT scientists have gone this one better, adding chemicals like iodine chloride or iodine bromide to make the atoms flake off in more-even layers.
These flakes are already good enough to build transistors, although more work still needs to be done.
This is the biggest promise of graphene – as a replacement for the silicon that’s been used to make transistors for over 50 years. With graphene transistors, almost any electronic device will work faster and use less power.
You could download a 3-D high-definition movie in mere seconds; using today’s technology, it’s 45 minutes.
Here’s the most far-out graphene development of the last two weeks – a cloak of invisibility, just like those Klingon warships had on Star Trek.
Researchers at the University of Texas are manipulating graphene to develop an “active, dynamically tunable invisibility cloak.” Basically, it involves bombarding the graphene with microwaves.
While it’s possible to use this graphene to make aircraft invisible, a more likely near-term use is noninvasive sensors – think medical imaging devices that won’t do the harm X-rays do.
No wonder the discovery of graphene won the 2010 Nobel Prize in physics.
But here’s the thing: For something that goes into a plain old No. 2 pencil, graphite is a lot less common a substance than you’d think…
“Good graphite is not that easy to find,” remarks our resident geologist Byron King. “Graphite prices have more than doubled in recent years. Based on recent quotes, a ton of 97% pure graphite goes for over $2,000. A ton of ultra-pure, 99.99% graphite will set you back over $20,000.”
Another wrinkle: “China controls 80% of the global graphite market – just like China runs 97% of the world supply of rare earths. But the Chinese are running low on graphite reserves – same story as with rare earths.”
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