Magic Rocks

After a "breakthrough" in nanocrystal research, what's next?

2 min read

This week comes news of a breakthrough in nanocrystal research.  Scientists at the United State's Energy Argonne National Laboratory and the Carnegie Institution of Washington report finally being able to watch nanocrystals grow into form. "We have not been able to see how different conditions affect the particles," said Wenge Yang of the Carnegie Institution's Geophysical Laboratory, "much less understand how we can tweak the conditions to get a desired effect."

"Nanocrystal growth is the foundation of nanotechnology," said lead researcher Yugang Sun, "Understanding it will allow scientists to more precisely tailor new and fascinating nanoparticle properties."  As the so-called "foundation of nanotechnology," nanocrystals have fascinating prospects, as I learned from an engineer working in the field in Princeton.  Nanocrystals are in your socks, your Armani suit.  They're making his way into your cosmetics, your credit cards, your smart car.   And if you have lung cancer, he could be inside her chest too.

Entrepreneurial physicists are making and selling nanocrystals: programmable particles that are infiltrating our everyday lives.   Once a security measure of the Department of Treasury, nanocrystals are now going wide and transforming our lives. Grown from patent-protected mixtures of rare-earth elements – with names like Ytturbium, Prometheum, and Neodymium – these crystals measure as small as one nanometer.  Together they create something extraordinary, light.  Each mixture of elements produces a unique optical signature that can be detected with an infrared sensor.  With infinite combinations possible, there are countless types of light that can be produced – different colors, sizes, wavelengths.  And this is where the burgeoning applications come in. 

At first, nanocrystals were used to fight counterfeiters  The Department of Treasury puts nanocrystals in cash for added security.  If you hold a $20 bill up to an infrared sensor, you’ll see faint streaks of blue and green light – impossible to duplicate. A major credit card company will be putting the crystals into credit cards next year.  Lycra puts nanocrystals in its clothing to detect knockoffs.  If you hold a sensor up to your socks right now, you’ll see the crystals glow.

But the magic rocks aren’t just for security anymore.  They can be used  to improve the efficiency of solar cells.  Researchers are using nanocrystals to illuminate and track lung cancer cells in patients (a key development, because tumors can now be tracked without cutting open a patient’s chest).  Cosmetics companies could create nanocrystal infused makeup that creates a pinkish glow when exposed to sunlight.  Carnegie Mellon’s Robotics Institute developed an auto-guiding car that senses and follows a trail of nanocrystals on a white line on the road. 

Is this the dawn of the Rare Earth age?

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The Transistor at 75

The past, present, and future of the modern world’s most important invention

1 min read
A photo of a birthday cake with 75 written on it.
Lisa Sheehan
LightGreen

Seventy-five years is a long time. It’s so long that most of us don’t remember a time before the transistor, and long enough for many engineers to have devoted entire careers to its use and development. In honor of this most important of technological achievements, this issue’s package of articles explores the transistor’s historical journey and potential future.

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