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Gold Nanoparticles Turn Trees Into Streetlights
An anonymous reader writes "Street lights are an important part of our urban infrastructure — they light our way home and make the roads safe at night. But what if we could create natural street lights that don't need electricity to power them? A group of scientists in Taiwan recently discovered that placing gold nanoparticles within the leaves of trees causes them to give off a luminous reddish glow. The idea of using trees to replace street lights is an ingenious one — not only would it save on electricity costs and cut CO2 emissions, but it could also greatly reduce light pollution in major cities."
And it is very cheap.
So it appears as though the effect requires an outside energy source to be useful. Nothing to see here, move on.
Dog is my co-pilot.
The article says:
...A lot of light emitting diode, especially white light emitting diode, uses phosphor powder to stimulate light of different wavelengths. However, phosphor powder is highly toxic and its price is expensive. As a result, Dr. Yen-Hsun Wu had the idea to discover a method that is less toxic to replace phosphor powder. ...
By implanting the gold nanoparticles into the leaves of the Bacopa caroliniana plants, the scientists were able to induce the chlorophyll in the leaves to produce a red emission. Under a high wavelength of ultraviolet light, the gold nanoparticles were able to produce a blue-violet fluorescence to trigger a red emission in the surrounding chlorophyll.
So it sounds like the trees need a "high wavelength of ultraviolet light" to get them to glow. Seems like they are just replacing the phosphor that makes a white LED glow with these gold implanted leaves. But you'd still need a UV light source (which could be an array of UV LED's?).
I'm not sure that this is really an environmental win -- replacing an array of white LED's that last 10 years with an array of UV LED's that point to trees that need their leaves to be impregnated with gold (and replaced annually?) doesn't sound all that environmentally friendly. How bad is the LED phosphor for the environment?
Once again, proof that journalists should just stick to describing the research rather than coming up with groundbreaking applications which, as you'd almost certainly expect, don't work. The nanoparticles don't make the leaves glow "naturally", you have to shine UV light on them. Then they fluoresce red. But if you want to light streets using this technology, can I recommend just coating the UV light with leaves and doing away with the tree (we don't want to waste UV light after all)? In fact, ignore the leaves - just use a fluorophore. Actually, better yet, why not use a fluorophore that doesn't emit red light? How about something more akin to natural light, like yellow? And make it sensitive to blue light rather than UV (because generating UV is harder). And finally, while we're at it, make the light source solid-state.
Congratulations, you've just invented the white LED.
Yes! And the additional health-benefit of inhaling loose, blowing nano-particles - and the subsequent introduction to the pulmonary systems of city-dwellers - is surely the cincher on this!
"Flyin' in just a sweet place,
Never been known to fail..."
Read the article. The trees don't just glow...they glow because a UV light is shining on it, converting the UV to visible, similar to a standard fluorescent light...except with a standard light, you get nearly all of the UV interacting with the fluorescing particles...and it doesn't have to go through glass, which isn't so good/cheap at transmitting UV.
"Mushrooms are fungi and trees are plants... you may as well try and cross a dog with a sunflower."
I'm not sure why everyone seems to have scored this comment as insightful, considering that back in 1986 scientists took the "glowing" genes of fireflies and spliced them into the tobacco plant, which resulted in fields of glowing tobacco.
http://www.time.com/time/magazine/article/0,9171,962873-2,00.html
Insects and plants are probably more difficult to splice than fungi and plants, but just guessing...
you may as well try and cross a dog with a sunflower.
Well, looks like it's possible after all.
No, there is no "-1 I'LL NEVER ADMIT BEING WRONG!!!" mod.
Gold is non-bioreactive in humans. It won't matter if it enters our lungs, as it doesn't cause any issues.
My blog. Good stuff (when I remember to update it). Read it.
Tell that to the crack heads who destroy a $10,000 air conditioner for $20 in copper.
"You should always go to other people's funerals; otherwise, they won't come to yours." -- Yogi Berra
Infinity isn't a number. If anything, the concept represents a "really really big positive number" in this context, in which case, yes, if you add something greater than 0 to that really really big number, then you will have an even bigger number.
The interesting thing about "Infinities", is that they are not all created equal.
Take for instance, these two infinite sets:
All even numbers.
All numbers divisible by 4.
the first one is provably larger than the second, while both are infinite quantities. (In fact, the second is a provable subset of the first.)
This is why "Infinity" is not a "Value".