HOUSTON -- (Nov. 19, 2012) -- Serendipity proved to be a key ingredient for the latest nanoparticles discovered at Rice University. The new "lava dot" particles were discovered accidentally when researchers stumbled upon a way of using molten droplets of metal salt to make hollow, coated versions of a nanotech staple called quantum dots.
The results appear online this week in the journal Nanotechnology. The researchers also found that lava dots arrange themselves in evenly spaced patterns on flat surfaces, thanks in part to a soft outer coating that can alter its shape when the particles are tightly packed.
"We're exploring potential of using these particles as catalysts for hydrogen production, as chemical sensors and as components in solar cells, but the main point of this paper is how we make these materials," said co-author Michael Wong, professor of chemical and biomolecular engineering at Rice. "We came up with this 'molten-droplet synthesis' technique and found we can use the same process to make hollow nano-size particles out of several kinds of elements. The upshot is that this discovery is about a whole family of particles rather than one specific composition."
Like their quantum dot cousins, Rice's lava dots can be made of semiconductors like cadmium selenide and zinc sulfide.
Wong's lab has been working steadily to improve the synthesis of quantum dots for more than five years. In 2007, Wong's team discovered a cleaner and cheaper way to synthesize four-legged quantum dots -- particles smaller than a living cell that look like tiny versions of children's jacks. These "nanojacks," which are also called quantum tetrapods, can be used to harvest sunlight in a revolutionary new kind of solar panel.
The key step in the 2007 discovery was the use of a surfactant called CTAB. In 2010 Rice graduate student Sravani Gullapalli was attempting to refine the "nanojack" synthesis even further when she discover
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