In the production of glass, alchemists of the Middle Ages added various substances to the molten mass, including gold and silver chloride, and obtained wonderful colors. When the sun's rays passed through the stained-glass windows of the temples, unique shades of all kinds of combinations were obtained.
It may seem incredible, but already at that time (quite by accident!), Quantum dot nanotechnology was discovered, the practical use of which in electronics is only now gaining momentum. Today we rush to the TV every day after work to once again enjoy the realistic picture displayed on the screen.
TV milestones
Since the 50s of the last century, when the TV became commonplace in our homes, it has improved, going from a bulky box with a picture tube to a flat, almost weightless plasma on the entire wall, successively changing abbreviations in the data sheet: LCD, LED, HD, 3D … And now we are on the cusp of a completely new QD (Quantum Dot) technology.
At the dawn of the television era, the image was obtained only in black and white, although research on the transfer of the entire palette on the screen was in full swing, and after a very short time, viewers could already enjoy the color image. LCD TVs, which were very popular in the early 2000s, took over. They were replaced by LCD TVs. Image quality and color reproduction are greatly improved by illuminating the back of the screen with LEDs.
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Behind each abbreviation there is a huge work of scientists and industrialists who have introduced new technologies into practice. And now we see the result of their work every day, observing a realistic picture of events without leaving home.
The era of the quantum dot has already been
And now, almost 10 centuries after the involuntary discovery of medieval alchemists, quantum dots were rediscovered at once by two scientists - the Russian physicist A. Yekimov in 1980 and the American chemist Louis E. Bruce in 1982.
They found that breaking a semiconducting material in the presence of nanoparticles (which are not much larger than water molecules) reveals completely new material properties.
Scientists made an important discovery: the wavelength emitted by each particle changed depending on their size. This makes it possible to reproduce all colors in the range visible to the human eye. What caused this phenomenon? Changing the energy of the "band gap", one of the fundamental characteristics of a semiconductor.
What conclusion can be drawn from this information? If the amount of energy of quantum dots can be controlled by the outgoing signal, they can be perfectly used to convey all the colors of the rainbow.
An important discovery
University of California professor Paul Alivisatos, who studies nanotechnology, took a close look at the structure of the human eye. He realized that for a better perception of the television image, the light radiation from the display must correspond to the natural radiation to which the receptors of the human organ of vision are accustomed.
And this is what Dr. Alivisatos did. By studying nanoparticles (which are milliard fractions of a meter in diameter), in his laboratory, he refined the production of nanocrystals, now known as quantum dots.
From theory to practical implementation - one step
So it turned out that many of today's revolutionary discoveries in the field of nanotechnology have roots in the distant (or not so distant past). Medieval alchemists quite accidentally, on an intuitive level, discovered a way to use quantum dots in practice.
As we have seen, when quantum dots come into contact with light, they convert this radiant energy into virtually any color in the visible spectrum. “Quantum dots on the display are perfectly perceived by our eyes and therefore can represent colors realistically,” said Dr. Alivisatos.
The use of quantum dot technology will reduce production costs and increase the service life of devices, however, it has not yet come to practical use. The fact is that now the prototypes use cadmium, which is extremely toxic to the human body. However, Samsung Corporation, which claims to be a practical application of the technology, says it will take a few years to bridge the gap between theory and practice. The use of nanoparticles for image transmission is a question for the near future.
Marina Popova