In 2023, scientists Moungi Bawendi, Louis Brus and Alexei Ekimov won the Nobel Prize in Chemistry for their work on quantum dots and nanotechnology. According to the prestigious awards committee, they received the Nobel Prize for “the discovery and synthesis of quantum dots.”
What are quantum dots?
Quantum dots are semiconductor nanostructures that, due to their tiny size, exhibit unique optical properties. They are used in applications such as improving image quality in displays and light detection in electronic devices.
In the tiny nano world, measurements are made on scales of millionths of a millimeter, and everything works noticeably different compared to the everyday world. Examples of this peculiarity are manifested in areas such as television technology and the manufacture of colored glass.
Although the production of colored glass has been rooted in history for thousands of years, practically since people discovered glass. Curious minds have been intrigued by the enigma of generating the different shades of these materials. For a long time, people believed that impurities played a key role in the diversity of colors that could be achieved in glass.
Until the 16th century, they created the technique to color glass at will. Although they discovered that with the same substance they could make glass of different colors, depending on what temperature they heated it to or how they cooled it.
The Beginnings of Alexei Ekimov’s Research in His Field of Study
This is how Alexei Ekimov began his study, upon learning that different results could be obtained with the same substance. He began to tint glass with copper chloride using different methods. He used temperatures from 500º to 700°C, with variable time ranges, from 60 minutes to 96 hours. He noticed that copper chloride crystals had disparate measurements ranging from 2 nanometers to 30 nanometers.
The most striking thing is that the largest crystals were the expected red color, while the smallest ones varied their colors as they became smaller. They went from orange to yellow, then to green and finally to blue.
The answer to this synchrony was sought in quantum. For this reason, already in 1981, Ekimov was the first scientist to deliberately create quantum dots. However, the world did not find out about his discovery, as he published it in the Soviet Union and never shared it with the rest of the world.
The Investigation of Louis Brus and Moungi Bawendi
Meanwhile, Louis Brus worked with chemical reactions and the application of solar energy. In 1983 he discovered that one of the solutions had changed color. A phenomenon very similar to the one Ekimov investigated. Thanks to these discoveries, today we know that the properties of the elements in the periodic table also depend on their size.
Moungi Bawendi, in 1993, working for MIT, managed to saturate a solvent exposed to heat, generating small crystal points.
Currently, quantum dots are pillars of nanotechnology and widely used in the world in which we live. Television screens or computer monitors use QLED technology, based on quantum dots.
Quantum dots are what allow a light-emitting diode (LED) to go from blue to red and then to green. We owe the discovery of quantum dots to these three scientists who, without a doubt, deserved the Nobel Prize in Chemistry.
