LED light is a judge's semiconductor diode

Today, light-emitting diodes (LEDs) are used in large numbers in everyday life. The increasing share of LED lighting products in the market also indicates its great development prospects. The advantage of LEDs is that the volume can be compressed to a small size and produce a point source.

How small is the smallest LED? Recently, researchers from the Institute of Materials Physics and Chemistry of Strasbourg, France, the University of Paris and the French Atomic Energy Commission collaborated to develop the first LED composed of a single molecule, successfully challenging the limits of LED minimization.

The international authoritative physics journal "Physical Review Letter" published the research results not long ago. French researchers fixed one end of a polythiophene wire to the probe of a scanning tunneling microscope and the other end to a gold surface. Polythiophene is a polymer molecule composed of hydrogen, carbon and sulfur. It is a good conductor of electricity and is used in the manufacture of LED lighting products. Experiments have shown that when current passes through this nanowire, it produces light.

This study subtly reveals the interaction of electrons and photons in a very small range. Scientists have observed that the principle of luminescence of polythiophene lines is the same as that of LEDs: LEDs are semiconductor diodes that emit light when current is passed through, and are single-conducting (ie, can only conduct electricity in one direction). Similarly, the polythiophene line will only illuminate when electrons flow from the end of the scanning tunnel display probe to the gold surface. When the polarity of the power supply is reversed, the generated light energy is negligible.

Experiments have shown that when a negative charge (electron) is combined with a positive charge (hole) through a polythiophene line and most of its energy is transferred to a photon, luminescence occurs. Every 100,000 electrons pass through the polythiophene line, and a photon can be emitted. This groundbreaking research also laid the foundation for the future development of molecular computers.