Nobel Chemistry 2023 goes to adding color to nanotechnology – 10/04/2023 – Science

The 2023 Nobel Prize in Chemistry went to research related to the discovery of quantum dots, which gave color to nanotechnology. The discovery is currently present in televisions and monitors with QLED technology — the “Q” refers exactly to quantum dots —, LED lamps and can also be used in medicine, to guide the removal of tumor tissue.

The winners were Moungi Bawendi, from MIT (Massachusetts Institute of Technology), Louis Brus, from Columbia University, and Alexei Ekimov, from Nanocrystals Technology Inc., all institutes in the United States. The announcement was made this Wednesday morning (4), at the Royal Swedish Academy of Sciences, in Stockholm, Sweden.

The winners will equally share 11 million Swedish kronor (just under US$1 million), a medal and a diploma.

“Very surprised, sleepy, shocked and very honored,” said Bawendi, one of the laureates, about receiving the award, over the phone, during the Nobel announcement. Traditionally, the Royal Swedish Academy of Sciences calls laureates around the world on the morning the Nobel Prize is announced.

Quantum dots are crystals, made up of a few thousand atoms, so small that their size determines their physical properties.

With bright colored tubes worthy of a low-budget science fiction film, Johan Aqvist, president of the Nobel Committee for Chemistry, materialized part of the potential of quantum dots.

“What you’re seeing are quantum dots in a liquid solution,” he said. “The nanoparticles in each of the vials are made of the same simple substance. So how do they differ in color? It’s a quantum effect. The particles are so small that their electrons start to get crowded. The smallest quantum dots glow blue and the biggest ones in yellow and red. They only differ in size, nothing else.”

Theoretically, it was already known that size-related quantum effects could be present in nanoparticles, but the application of this, until decades ago, was unthinkable. Until Alexei Ekimov, born in the then Soviet Union, created such effects in colored glass, using copper chloride, in the 1980s.

Next came Louis Brus’ contribution to the area. And at this point, you may already be asking yourself: “so what, how important is the color difference?”.

Brus was studying how some particles can capture light and use the energy obtained in reactions. Brus used very small particles. Interestingly, after some time on the laboratory bench, the particles had changes in optical properties. The scientist then noticed a difference in light absorption.

Once again: “so what?”

Well, optical changes indicate total changes in the characteristics of a substance. The change in absorption indicates an entirely new material. This is because such optical properties are linked to electrons, which are also related to electrical conductivity and the potential to catalyze chemical reactions.

It may not yet seem impressive, but this discovery can be defined as the addition of a third dimension to the periodic table. Basically, properties of elements are not only affected by the number of electronic shells in an atom and the number of electrons in it. At the nanoscale, size also counts.

What Brus did, however, had a limitation: the basically unpredictable quality of the crystals created.

Finally, in 1993, came the contribution of Moungi Bawendi, who had previously worked in Brus’s laboratory.

Bawendi and his research group, in a specific heated solvent, injected a substance that would form nanocrystals in sufficient quantity to saturate the solution. This led to the creation of small crystal embryos, which formed simultaneously.

By varying the temperature of the solution, the research team was able to create nanocrystals —almost perfect in their shape—of specific sizes.

The uses of quantum dots

The materialization of this year’s Nobel Prize in Chemistry may already be in your home, on QLED monitors and televisions — interestingly, the 2014 Nobel Prize in Physics is also related to LED technology. The work could also have an important impact on medicine and biochemistry.

Quantum dots are used, for example, linked to biomolecules that map human organs. The use of these points to locate tumors in the body is also being investigated.

This type of technology is also expected to be part of flexible electronics, solar cells, even smaller sensors and even encrypted quantum communication.

Accidental disclosure of the names that would be laureates

This year’s Nobel Prize in Chemistry was marked by the announcement by email, early in the Swedish morning, of the names that would receive the award at the end of the Swedish morning. The meeting to make the final decision on the winners, however, takes place, in theory, shortly before the winners are announced to the rest of the world.

During the award press conference, Hans Ellegren, secretary general of the Royal Swedish Academy of Sciences, was repeatedly asked about the fact. “No decision is made until it has been made,” said Ellegren, regarding the announcement prior to the meeting itself to hammer out the names of the laureates.

“A press release was sent out for unknown reasons. We were very active in trying to find out what happened, but we don’t know. We are deeply sorry that this happened. The important thing is that it did not affect the award recipients in any way,” said Ellegren , running over and exchanging a few words at the end of his speech. “Nominating Nobel Prizes is a very long process and the decision on the prize is not made until the academy meets, and the academy met this morning.”

Chemistry or Physics

During the press conference, the relationship between the line of research awarded at the Nobel Prize in Chemistry and the area of ​​physics as a whole was also raised.

“I would say there is a root of this field in semiconductor physics,” said Heiner Linke, a member of the Nobel Committee for Chemistry and an expert in the laureate’s field.

According to Linke, the quantum phenomena present, for example, in optoelectronics are more related to instruments than to materials.

“The discovery here is to purify quantum effects and turn them into materials. You can touch, you can dry these quantum dots. You have powders that still have these properties of this new material. The methods for doing this come from chemistry. And are chemical methods to continue to treat and make use of in biomedical applications,” said Linke.

How the Nobel Prize winner is chosen

The Nobel Prize began with the death of Swedish chemist Alfred Nobel (1833-1896). In his will, in 1895, Nobel recorded that the fortune he left should be used to build a prize. The chemist’s family received the idea with objection. The first prize ended up being given only in 1901.

For the work of Nobel, inventor of dynamite and responsible for the development of synthetic rubber and leather, chemistry was the most important science. The chemist registered 355 patents in his 63 years of life.

The process of choosing the winner in the chemistry area begins the year before the award. In September, the Nobel Committee for Chemistry sends out invitations (around 3,000) to nominate names that deserve the honor. Responses are sent by January 31st.

Members of the Royal Swedish Academy of Sciences may nominate names; members of the Nobel Committee for Chemistry and Physics; Nobel Prize winners in Physics and Chemistry; chemistry professors at universities and technology institutes in Sweden, Denmark, Finland, Iceland and Norway, and at the Karolinska Institute in Stockholm; professors in similar positions in at least six other (but normally hundreds of) universities chosen by the Academy of Sciences, with the aim of ensuring adequate distribution across continents and areas of knowledge; and other scientists that the Academy deems appropriate to receive the invitations.

Self-nominations are not accepted.

A process of analyzing the hundreds of names chosen then begins, with consultation with experts and the development of reports, in order to narrow down the selection. Finally, in October, the Academy, by majority vote, decides who will receive recognition.

Recent history of the Nobel Prize in Chemistry

In 2022, the Nobel Prize in Chemistry went to Carolyn Bertozzi, Morten Meldal and Barry Sharples, for the development of an ingenious tool for building molecules. Scientists are responsible for studies on so-called “click” chemistry and bio-orthogonal chemistry.

In 2021, the award went to Benjamin List, from the Max-Planck Institute, in Germany, and David MacMillan, from Princeton University, in the USA. Scientists were awarded prizes for developing an ingenious and powerful tool for building organic molecules, known as asymmetric organocatalysis.

In 2020, the Nobel Prize in Chemistry was 100% female, with honors going to Emmanuelle Charpentier, from the Max Planck Institute (Germany), and Jennifer Doudna, from the University of California, Berkeley (USA). The researchers were important in opening the door to the possibility of rewriting the code of life with gene editing. You may have already heard of the technique used for this: Crispr-Cas9.

In 2019, the development of lithium-ion batteries earned John B. Goodenough, M. Stanley Whittingham and Akira Yoshino the Nobel Prize in the field.

For taking evolution to test tubes, in 2018, the Nobel Prize in Chemistry went to Frances H. Arnold, from the USA, George P. Smith, also from the USA, and Gregory P. Winter, from the United Kingdom.

In 2017, research into electron cryomicroscopy, a process by which it is possible to freeze molecules in the midst of biochemical processes — as in a photograph of life —, was recognized by the Nobel Prize. The laureates were Jacques Dubochet, from the University of Lausanne, Joachim Frank, from Columbia University and Richard Henderson, from the University of Cambridge.