This month, researchers from the Institut de Physique et de Chimie des Matériaux de Strasbourg made the outstanding announcement that they created a single-molecule LED. To grasp the significance of this development, perhaps we have to revisit the actual meaning of LED.
LED is an acronym for Light Emitting Diode. A diode is an electronic cell. LEDs are actually semiconductor diodes – meaning they create light when an electric current passes through them.
So the resulting component need not resemble the LEDs you’d find on a typical replacement bulb or any other lighting-class LED fixture. But the term still applies even on a molecular scale – as long as it’s a Diode that Emits Light, you’ve got yourself an LED.
The researchers used a single polythiophene wire, composed of hydrogen, carbon and sulfur atoms. (These elements make great conductors, and are commonly used in lighting class LEDs.) One end of the polythiophene wire was attached to a gold surface, and the other to a scanning tunneling microscope. The researchers found that the negative charge of the electron, met with the positive charge in the wire, combined and turned that energy into a photon of light as it traveled towards the gold. (Read PhysOrg for more details.)
The single-molecule LED is unlikely to reach the general lighting market anytime soon, as it has more immediate applications in the development of nano-computers. However, this research illuminates the conductivity of materials which can create more powerful lighting class LEDs, and also grows our understanding of quantum physics – all ways that a little LED can make a BIG splash.