Graphene, the one atom thick carbon material, the current miracle material of nanotechnology is poised to become the next big thing in lighting.
On the left is an optical image (scale bar at 5 mm) and on the right is a micrograph
(scale bar at 5 μm) of the bright visible-light emission from suspended graphene.
(Courtesy: Young Duck Kim/Columbia Engineering)
As announced in June, a team led by Young Duck Kim now at Columbia University, formerly at Seol National University, discovered the light emission during the course of experiments with suspended graphene. Since moving to Columbia Kim has been developing variations on the structure of the graphene to improve light output. At present the light emission is tiny and likely to have more application within electronic devices for optical communication, however this is where LEDs started out. The emission from Graphene would seem to be on the black body curve and currently around 2800 Kelvin, right where we are used to with incandescent lamps. Essentially this is an incandescent like light source using a version of carbon so we are heading back to the materials used by Swann and Edison at the end of the 19th century!
As with previous attempts to improve the conventional incandescent technology, the interesting efficiency improvements are likely to be linked to a far higher photon extraction rate than is possible with a solid wire. The nano scale also offers other nano technologies to allow change in spectral distribution such as quantum dots and also nano scale optics using equally exotic materials and techniques. Development of this technology to produce a lamp suitable for general lighting is a really interesting prospect. Of course the efficiency of early products is likely to be low, the current lamp efficiency regulations in the EU and other countries are likely to slow down such developments and make it more expensive than necessary to bring this technology to market in the lighting field. Let us hope that enthusiasm for this technology is matched by investment to bring this to market sooner rather than later. The advantages of a white based full spectrum light source for comfort health and well being cannot be underestimated.
This announcement is not to be confused with launch of the graphene coated LED back in April by Manchetser University that heralded cost and efficiency improvements for LED based replacement lamps. In this technology graphene is merely being used as an efficient conductor for conventional LED technology. We wait to see if this really does make a substantial change in the LED replacement lamp market.
Kevan Shaw 22 June 2015