Researchers Make White LED Light Bulbs using Salmon DNA : TreeHugger

I'm Not Kidding
By now there's little doubt that LED-based lightbulbs are the future, and while a lot of cool LED technology still needs to make its way from the lab to the store, it's exciting to see that engineers are still finding new ways to squeeze more performance out of those semiconductor diodes. The latest breakthrough comes from the University of Connecticut, and it uses salmon DNA to create very long-lasting white LEDs (though they can be tuned to other colors). Read on for more details.

dna double helix image

A Bit More Technical Information About the Salmon DNA LEDs
Fluorescent dyes (two different ones, spaced between 2 and 10 nanometers from each other) are added to the DNA molecules, which are then spun into nanofibers. These are very durable because DNA is a particularly strong polymer (it has to be!) (they should last 50 times longer than acrylic, for example).

A LED emitting ultra-violet light is then coated with the DNA nanofibers: "When UV light is shined on the material, one dye absorbs the energy and produces blue light. If the other dye molecule is at the right distance, it will absorb part of that blue-light energy and emit orange light." Using DNA has the benefit of orienting the dyes "in an optimum way for efficient [fluorescence energy transfer] to occur," according to David Walt, a chemistry professor at Tufts University.

To tune the light quality, all you need to do is vary the ratios of dye. The light can be tuned from cool white to warm white, for example.

Not Ready for the (LED) Limelight Yet
Unfortunately, numbers on how many lumens per watt these LEDs produce haven't been released yet (though that might just be because they're still improving them), so it's not clear if the main benefit from these will be the longer life, or if the extra fine tuning will also mean better light quality than other white LED (like those that use quantum dots, for example), or if energy efficiency will also be superior. But it's a new trick that will no doubt be useful.

I'm a bit sick of writing this phrase - "it's too early to tell" - but that's how it is with discoveries straight out of the lab. Maybe someday we'll have a bit of DNA in our lights...

Via Technology Review

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