Nobel hits a quantum dot

The Nobel Prize in Chemistry in 2023 was awarded for “the discovery and synthesis of quantum dots.” The laureates were American scientists Muni Bavendi and Louis Bruce, as well as physicist Alexey Ekimov, who was born in the USSR and has been working in the USA since 1999. Answering questions from journalists about the appropriateness of awarding a Russian scientist against the backdrop of hostilities waged by Russia, the committee stated that for science “nationality does not matter.” It was Alexey Ekimov’s experiment, conducted back in the Soviet Union, that paved the way for subsequent research and technology. The Nobel Committee explained that the laureates “managed to create particles so small that their properties are determined by quantum phenomena.” Today, this technology is used in TV screens, LED lamps, and even in the removal of cancerous tumors. Experts note that “quantum dots” have been waiting for a Nobel Prize for a long time, and believe that in the future they may be awarded more than once for discoveries in this area.

Nobel Prize in Chemistry awarded 62-year-old Massachusetts Institute of Technology (USA) professor Muni Bawendi, 80-year-old Columbia University (USA) professor Louis Bruce and 78-year-old chief scientist of Nanocrystals Technology Inc. (USA) Alexey Ekimov. Thanks to their research, it was possible to discover and then begin to synthesize “quantum dots,” the Nobel Committee reported.

A “quantum dot” (quantum dot, QD) is not individual elementary particles, but systems consisting of tens and hundreds of thousands of atoms and molecules.

“When matter is compressed to nanoscale dimensions, quantum phenomena occur. The 2023 Nobel laureates in chemistry managed to create nanoparticles so tiny that their properties are determined by these phenomena,” explained the Nobel Committee. They also noted that “quantum dots” are of great importance in nanotechnology.

The occurrence of size-dependent quantum effects in nanoparticles has long been known, but before the laureates’ experiments, few believed that this knowledge was applicable in practice. However, in the early 1980s, Alexey Ekimov created quantum effects in colored glass using copper chloride nanoparticles. A few years later, Louis Bruce published a paper on semiconductor microcrystals in colloidal solutions, which were later called colloidal quantum dots. In 1993, Muni Bavendi was able to “grow” high-quality quantum dots with the necessary properties for practical use.

“Quantum dots now illuminate QLED computer monitors and television screens, tint the light of some LED lamps, and are used by biochemists and doctors to map biological tissues. In the future, they could contribute to flexible electronics, tiny sensors, thinner solar cells and encrypted quantum communications – so we have only just begun to explore the potential of these tiny particles,” the Nobel committee said.

It should be noted that during the ceremony, journalists asked committee members why the award was awarded to a Russian scientist against the backdrop of Russia’s military operations in Ukraine. “When it comes to selecting Nobel Prize winners, we simply follow a procedure for identifying the most important discoveries,” answered Secretary General of the Royal Swedish Academy of Sciences Hans Ellegren.—We then identify the most important contributors to these discoveries, without regard to nationality or any other factors. Nationality doesn’t matter here. Moreover, this exactly corresponds to the will of Alfred Nobel, who said that the prize should be given to the most worthy person, regardless of nationality.”

Note that in 2022 the Nobel Prize was awarded for “the creation of tools that make it possible to obtain given molecules under any conditions.” The winners were the developers of click chemistry, Americans Caroline Bertozzi and Barry Sharpless, as well as their Danish colleague Morten Meldahl. At the same time, Barry Sharpless’s research group included the Russian scientist Valery Fokin, whom Thompson Reuters experts had previously nominated for the prize, but he did not become a laureate, but Mr. Sharpless received the prize for the second time. Anton Shetnev, a researcher at the Laboratory of Molecular Biological and Neurobiological Problems and Bioscreening at MIPT, is confident that in research on “quantum dots” it would be simply impossible to bypass the name of the Russian scientist, since it was he who laid the foundation for the further development of the topic. “It’s strange that the Nobel Prize was not awarded for this discovery for so long, because the development has long been actively used in various fields,” the scientist notes.

Roman Vasiliev, associate professor of the Faculty of Chemistry at Moscow State University, agrees with him: “Experts have been betting that the Nobel Prize will be awarded for quantum dots for many years.” Ekimov and Bruce’s discoveries showed that “by changing the size of a semiconductor crystal, you can change the energy of the electrons in this crystal,” he says. This gave rise to “a huge wave of scientific work in the 90s,” and today the development is used so actively that “in the future we can expect several more Nobels for the revolutionary use of this technology.” “Thanks to this, it is possible to manipulate matter with single-atom precision, without using expensive equipment. This made it possible to move from the field of physics and installations, which occupy an entire floor, to chemists and a flask in the laboratory,” notes Mr. Vasiliev.

“The developments of the current Nobel laureates are also a great achievement from the point of view of optics,” notes Rostislav Starikov, head of the Laboratory of Photonics and Optical Information Processing at National Research Nuclear University MEPhI. “Technologies using quantum dots make it possible to create new light sources, in particular laser study sources with specified characteristics – for example, with synchronized mods.” Thanks to the synchronization of electromagnetic oscillations of laser radiation, lasers with ultrashort pulse durations are obtained.

Mr. Starikov also emphasized that in Russia, students of another Nobel laureate are studying “quantum dot” technologies and their application in laser technology. Zhores Alferov (2000 Physics Prize, shared with Herbert Kremer and Jack Kilby)

It is worth noting that the usual procedure for announcing Nobel laureates was disrupted today. The committee mistakenly sent a letter with the names of the winners ahead of schedule – journalists received the message at 7:30 local time, although traditionally the award is presented at 11:45 – and then announced that the final decision had not yet been made. For just over four hours, the intrigue remained whether the names would be changed during the official announcement, but this still did not happen. The award itself will be presented on December 10 in Stockholm: the laureates will share 11 million Swedish kronor (approximately $1 million).

Polina Yachmennikova