Among the industries seeking ways to make technology smaller, lighting is no exception. Now, a team of scientists at the University of Strasbourg in France has developed the first single-molecule light-emitting diode (LED).


The team placed a polythiophene wire between the tip of a scanning tunneling microscope and a gold surface. When they passed current through it in a certain direction, they found it emits light.


LEDs are components that emit light when an electric current passes through them. LEDs play an important role in everyday life as light indicators, but as electrical contractors are aware, they also have a promising future in the field of general-service lighting where they are making headway. 


A major advantage of LEDs is that it is possible to make them very small, so point light sources can be obtained.


Polythiophene is a good electricity conductor and is used to make larger LEDs that are already on the market. For the single-molecule LED, polythiophene wire was attached at one end to the tip of a scanning tunneling microscope and at the other end to a gold surface. The scientists recorded the light emitted when a current passed through this nanowire. They observed that the thiophene wire acts as an LED: light was only emitted when electrons went from the tip of the microscope towards the gold surface. When the polarity was reversed, light emission was negligible.


For practical applications, the team of scientists seem enamored with using the single-molecule LED in the development of a molecular computer, an achievement the computing world has sought for some time. However, moving forward, it isn’t hard to see the advantage of increasingly smaller lighting fixtures that produce enough lumens to illuminate a space without taking up so much room.


One thing is certain, though. While lamps may get smaller, they will always need current to generate light, so even as LEDs are now being made so small that they all but disappear, the need to run power to them will not.