Researchers at CNRS in France have created the first single molecule LED. The device, formed from a single polythiophene chain placed between the tip of a scanning tunneling microscope and a gold surface, emits light only when the current passes in a certain direction. This experiment sheds light on the interactions between electrons and photons at the smallest scales, and represents another step towards creating components for a molecular computer in the future. Light emitting diodes are components that emit light when an electric current passes through them and only let light through in one direction. 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 conductor of electricity, and is used to make larger LEDs already on the market. This device gives researchers a new tool to investigate phenomena that are produced when an electrical conductor emits light and it does so at a scale where quantum physics takes precedence over classical physics. The researchers will also be able to optimize substances to produce more powerful light emissions.
Source: CNRS Press Release