Tiny Light Bulbs

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The electrospinning technique offers multiple advantages. Using the method, one should be able to make fibers with diameters of 50 nanometers or less, which could lead to even smaller light sources, Malliaras says. Plus, the technique should make fabricating nanoscale light emitters on practical lab-on-a-chip devices relatively easy, although one would still need to etch the gold electrodes.

"The distinguishing and extremely interesting aspect of this work is the minute size of the light sources they describe," says John de Mello, who researches nanoscale organic light-emitting devices at Imperial College London. Until now, organic light-emitting devices have typically been about one square millimeter in size, he says, which is ideal for standard lab-on-a-chip applications, such as detecting bacteria or proteins. But the nanometer-sized light sources would be important for niche applications requiring speed and a very small resolution--for example, monitoring how a chemical reaction is proceeding as chemicals flow through microfluidic channels. "This approach offers a means of dramatically improving the resolution of such measurements," de Mello says.

Much research remains to be done, however. For any practical application, the researchers would need to precisely control the arrangement of the fibers on the silicon substrate. But the work is a first step in making nanoscale light sources using a straightforward method, Malliaras says.

Says de Mello, "Once it's known there's a low-cost route to making sub-wavelength light sources, you can be sure somebody will find a use for them. That's the real excitement of this kind of work."