A team of international researchers have banded together in order to create the thinnest lightbulb in the world. It’s the world’s first commercially viable incandescent lightbulb.
The team of researchers included Young Duck Kim, project leader and postdoctoral research scientist in James Hone’s group at Columbia Engineering, a team of scientists from Columbia, Seoul National University (SNU), and Korea Research Institute of Standards and Science (KRISS).
They created a carbon-based filament using grapheme, a form of carbon that’s perfectly crystalline and no thicker than an atom, and demonstrated an on-chip visible light source for the first time in recorded history. Young Duck Kim stresses that the light is so intense that is even visible to the naked eye, without needing any additional magnification.
The team started by attaching small strips of graphene to metal electrodes, then suspended the strips above the substrate, and finally passed a current through the filaments in order to get them to heat up
James Hone, co-author and Wang Fon-Jen Professor of Mechanical Engineering at Columbia Engineering, gave a statement explaining that “We’ve created what is essentially the world’s thinnest light bulb. 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”.
Creating light in such small structures on the surfaces of chips is essential for developing fully integrated ‘photonic’ circuits that can do with light what semiconductor integrated circuits currently do with electric currents.
Other researchers previously tried to think up ways of achieving this, however they have not succeeded in putting an incandescent lightbulb onto a chip. Incandescent lightbulbs are knows as the world’s oldest and simplest sources of artificial light.
The main reason why such attempts failed in the past is because the lightbulb filament has to be extremely hot (think thousands of degrees Celsius) in order to be able to glow anywhere in the visible range, whereas micro-scale metal wires have trouble withstanding such high temperatures.
Not only that, but the heat transfer between the hot filament and its surroundings is extremely efficient at the microscale, which means that such structures could easily damage their surrounding chip, thus making them impractical.
The international team of researchers solved these problems by measuring the spectrum of light that the graphene was emitting, and noticing that it managed to reach temperatures of above 2500 degrees Celsius. That made it hot enough to glow brightly.
But what’s really interesting is that as once graphene heats up, it becomes a lot worse at conducting heat, and the high temperatures only affect small “hot spots”.
The researchers are currently trying to gather information on details such as how fast the thin lightbulbs can be turned on and off.
Image Source: phys.org