The invention of a practical, long-lasting lightbulb by Edison and Swan in 1879 was a turning point in the history of human civilization. Instead of expensive candles giving off weak light, you could have cheap lightbulbs that brighten up a room like daylight.
Of course, the lightbulb has undergone some changes recently. Power-hungry incandescent bulbs have been replaced by more efficient and longer-lasting CFLs and LEDs. However, incandescent bulbs might be on the way back, just not how you'd expect.
If you remember, incandescent bulbs work by sending an electrical current along a tungsten filament. The filament heats up to the point that it produces visible light. Unfortunately, it wastes a lot of electricity as heat.
You also can't scale it down very far because the filaments burn out faster. Two words: Christmas lights. If I never have to hunt down burned out bulbs again, I'll be happy.
Enter the wonder material graphene. I've talked about it before and how it could revolutionize just about everything.
One of the exciting things about graphene is how well it conducts electricity and heat. Unfortunately, that makes it a bad choice for a lightbulb filament because it can't heat enough to give off visible light.
However, researchers found that if you suspend a sheet of graphene away from other materials (usually it's lying on a substrate of silicon) and pump enough electricity through it, it's heat-conducting properties break down and it emits light.
Here's a video showing an animation of the effect.
OK, that's really cool, but how is this not a step backward for lighting? Graphene has a few features that elevate it about normal incandescent bulbs.
First, by adjusting the electrical current and surrounding materials, you can finely tune the wavelength of light. This is useful for fiber optics and other forms of light-based communication.
In fact, computer researchers expect that in the future all the data transfer in your computer, even between transistors, will happen via microscopic light pulses instead of copper wires. Graphene emitters could be a good candidate because of the next point.
Second, where normal filament bulbs burn out faster the smaller they get, graphene can work at microscopic levels with no problem. And being only an atom thick, it can work in transparent and flexible displays.
Of course, as with any other graphene development, the obstacle is going to be mass production. Scientists already have trouble making high-quality graphene at typical manufacturing levels, although some promising techniques have been demonstrated.
Suspending the graphene so it acts as a filament adds another level of difficulty. However, the researchers behind this project are confident it can be worked out in the future.