France successfully challenged LED minimum limit

Nowadays, LED (LED) is widely used in daily life. LED lighting products in the market share continues to expand, but also shows its huge prospects for development. The advantage of LED is that the volume can be compressed to a minimum, and a point light source is generated.

How small is the smallest LED? Recently, the French Strasbourg Research Institute of materials physics and chemistry, University of Paris 6 researchers and the French Atomic Energy Commission jointly developed the first consists of a single molecule of LED, successfully challenged the limit of LED minimization.

International authoritative physics journal Physical Review Letters published the results of this study not long ago. The French researchers fixed one end of a polythiophene line on the probe of a scanning tunneling microscope, and the other end on the gold surface. Polythiophene is a polymer molecule composed of hydrogen, carbon and sulfur. It is a good conductor of electricity for the manufacture of LED lighting products. Experiments show that when the electric current passes through the nanowire, it produces light.

The study subtly reveals the interaction between electrons and photons in a very small range. Scientists observed that polythiophene line light-emitting principle is the same as the LED: LED is a semiconductor diode when the electric current passes through it can emit light, with unidirectional conductivity (i.e. only one direction conductive). Similarly, only when the electrons flow from one end of the scanning tunnel display probe to the gold surface, the polythiophene line will shine. However, when the polarity of the power source is reversed, the energy produced is negligible.

It is shown that when a negative charge (electron) is combined with a positive charge (hole) through a polythiophene line, and most of the energy is transferred to the photon, the phenomenon of light emission occurs. Each of the 100 thousand electrons can emit a photon through the polythiophene line. This groundbreaking research results also laid the foundation for the future research and development of molecular computers.