Glow-in-the-dark devices, which emit visible light after exposure to sunlight, are as commonplace as a wristwatch. But these are not that great when you want to see and not be seen — say you're a special ops soldier checking the time while tracking an enemy. In that situation, a glow-in-the-night-vision device would be far more effective. Now scientists at the University of Georgia have invented just such a device — a new material that emits a long-lasting infrared glow after a single minute of exposure to light.
You can only see the light through night-vision glasses.
Visible-light phosphors have been around since 1996, and nowadays there's a chemical compound for every color. They're integrated into traffic signs, security signs, displays and much more, where they emit an afterglow hours after the light shone upon them has gone dark. Now Zhengwei Pan, a physics professor at UGA, has developed the first adaptable, long-lasting near-infrared phosphor, based on the trivalent chromium ion. Its electrons are excited in the presence of light and move to a higher energy state, then fall back to ground state. This energy loss is expressed in a flash of light in the near-infrared realm of the spectrum. But the flash doesn't last very long, so Pan and colleagues had to trap it.
Pan et al. use a matrix of zinc and a mineral called lanthanum gallogermanate, which holds the Cr+3 ions. The matrix serves as a labyrinth that captures this electron energy release and store it for an extended period. The afterglow intensity drops quickly at first, but slows down and then decays very slowly, the authors say. At room temperature, this stored energy is gradually released in the form of a continuous near-IR light display. It can last up to two weeks, the researchers say.
They tested it in natural sunlight, color-filtered sunlight and fluorescent light, and found it works with just a few seconds of light exposure, even on a cloudy day. It works in liquid, too, including tap water, saltwater and bleach, which could make it very useful for deep-sea applications or even in living organisms. The material could also be useful in developing more efficient solar cells, nanoparticles that bind to cancer cells, or in infrared paint only viewable by people with IR goggles, the researchers say. In the image above, Pan and postdoctoral researcher Feng Liu show off a UGA logo they made using the new phosphor. There is no external light in this image, a 4-second exposure shot using a night vision monocular.
The work is published in the early online edition of Nature Materials.
Can I buy one of these? I want to put a glowing " G ", on front of my super Grunt suit!!!;)
I want one that says flapjack :DDDD
I was excited until I saw "infrared," then I wondered what the hell that would be good for. Within seconds, I guessed military night operations. When I read further and saw that that was exactly the primary application for this new invention, I just rolled my eyes and sighed. I know this will probably be frowned upon, but I get tired of reading about science being used to invent new toys for the military. It seems like with every new military invention, there's this unspoken notion that it's okay if war continues because people will just keep using science to make warfare more efficient and convenient.
Little piece of human trivia.
"Those who plan for war, go to war!"
There are lots of things that wouldn't be around if the military didn't invent, or pay for it to be invented. GPS, Internet, RADAR, Walkie-talkie's, digital photography, jet engines, not to mention all the medical break throughs that have been used to save civilian lives. Just because the military invents or innovates something doesn't mean it's a killing machine ...
Necessity is the mother of invention yes.
So as DARPA plans for war and puts humans in harms war, they get killed or harmed; then DARPPA develops better technology to protect them and save their life.
It almost makes war to be a good goal....
What if we set the idea of war off to the side?
And just invent a GOAL of protecting people and saving life’s in the first place. With that goal being first, we may actual accomplish a lot more good without as much death and destruction.
You know, as a society we do set the priority of our goals.
Send a man off into war and he loses his leg.
You want that man to thank the sender for the prosthetic.
Maybe there is no war and one day do to an accident the man loses his leg and then we offer him a prosthetic, with the original intention to protect the man in the first place from the accident.
Well first off, why would you say we should put the goal of protecting people infront of war. It already is. Do you think we have a military just to go to war? Remember something called the cold war? Having the most advanced military in the world has something called a deterence factor that keeps us out of wars with other developed nations.
Secondly, there is a goal of saving people's lives, it's called the health care industry, and it's more out of control than government defense spending ...
I really applaud people like this that go out of their way to try to invent and create things that will help for the good of all. Good job guys. I think our technology and evolution is advancing at an exponential rate.
I'll write that procrastination essay tomorrow...
@Grunt 'Little piece of human trivia.
"Those who plan for war, go to war!"
Here is a lesson from history: Those who do not plan for war, are conquered.
@a2011 and democedes
Well said both of you! I was thinking of the same responses 'til I saw yours.
Developments like these refine our military and save more INNOCENT lives! The intent of a well-prepared, standing military force is: "Hope for the best, plan for the worst". I am in the Army and am not a "warmonger". But I think those that have the "peace at any cost" outlook are foolish. In order for that to happen, EVERYONE (including your "enemy") has to have the same view. I'm almost tempted to go on a rant, but I don't think this is the forum.