Researchers Create First Ever Single-Molecule LED
14 February 2014
The French Institut de Physique et de Chimie des Matériaux de Strasbourg has developed the first single-molecule light-emitting diode (LED). This accomplishment represents a huge leap forward in the creation of components for a molecular computer in the future by enabling the generation of molecule-sized components with both electronic and optical properties.
The success was achieved with the help of the Institut Parisien de Chimie Moléculaire and the French Atomic Agency and was recently detailed in the journal Physical Review Letters.
The single-molecule LED was developed from a single polythiophene wire mounted between the tip of a scanning tunneling microscope (STM) and a gold surface. The device releases light when the current passes through it in a certain direction.
The wire used for the device has strong electrical conductivity and is made of hydrogen, carbon and sulfur, and is already broadly used for the production of LEDs with larger sizes. When a current passed through this nanowire the research team analyzed the process, establishing that the thiophene wire serves as a light emitting diode, since light is only released when electrons pass from the tip of the microscope towards the gold surface. Light emission volumes proved insignificant when the polarity was reversed.
More specifically, this red light is released when an electron interacts with a positive charge in the nanowire and transfers most of its energy into a photon, which is emitted in the "red wavelength range" for every 100,000 electrons inserted in the wire.