A team of scientists have created the world’s thinnest light bulb using Graphene, an atomically thin and perfectly crystalline form of carbon.
They have demonstrated an on-chip visible light source using graphene, as a filament. They attached small strips of graphene to metal electrodes, suspended the strips above the substrate, and passed a current through the filaments to cause them to heat up.
“This new type of ‘broadband’ light emitter can be integrated into chips and will pave the way towards the realization of atomically thin, flexible, and transparent displays, and graphene-based on-chip optical communications.”
The ultrathin graphene was turned into a superheated filament – just like the thin wire of an incandescent light bulb – which glowed at a temperature of above 2500 degrees Celsius.
The visible light from atomically thin graphene is so intense that it is visible even to the naked eye, without any additional magnification.
The ability of graphene to achieve such high temperatures without melting the substrate or the metal electrodes is due to the interesting property: as it heats up, graphene becomes a much poorer conductor of heat. This means that the high temperatures stay confined to a small “hot spot” in the center.
“These unique thermal properties allow to heat the suspended graphene up to half of the temperature of the sun, and improve efficiency 1000 times, as compared to graphene on a solid substrate.”
The team also demonstrated the scalability of their technique by realizing large-scale of arrays of chemical-vapor-deposited (CVD) graphene light emitters.
Yun Daniel Park, professor at Seoul National University, notes that they are working with the same material that Thomas Edison used when he invented the incandescent light bulb: “Edison originally used carbon as a filament for his light bulb and here we are going back to the same element, but using it in its pure form—graphene—and at its ultimate size limit—one atom thick.”
The group is currently working to further characterize the performance of these devices—for example, how fast they can be turned on and off to create “bits” for optical communications—and to develop techniques for integrating them into flexible substrates.
Already a dimmable LED bulb with a graphene-coated filament was designed at Manchester University.
Original story posted in Advance Online Publication (AOP) on Nature Nanotechnology in 2015 (but the application is worth revisiting)