Two American scientists and a Russian have been awarded the 2023 Nobel prize in chemistry for the discovery and synthesis of quantum dots, which helped drive a revolution in nanotechnology.
The prize is shared equally between Moungi Bawendi, Louis Brus and Alexey Ekimov for discoveries on the unique properties of nano-materials, and how to make them, that paved the way for wide-ranging applications in consumer electronics, biochemistry and medicine.
Bawendi is an American chemist of French and Tunisian descent, based at MIT, Brus is based at Columbia University and Ekimov is chief scientist at Nanocrystals Technology, a New York-based company.
The official announcement came after the three names were leaked in an email to a Swedish newspaper earlier on Wednesday morning, in an embarrassing incident for the academy. Johan Åqvist, the chair of the academy’s Nobel committee for chemistry, said that at the time of the inadvertent email, the academy had not yet made a decision about the prize winners and, when asked, did not rule out the uncomfortable possibility that other scientists had been under consideration at the time.
“There was a press release sent out for still unknown reasons,” he said. “We deeply regret that this happened. The important thing is that it did not affect the recipients in any way.”
Åqvist said a decision on the winners was taken only at the morning meeting of the academy, which “is not just a formality”. “A decision is not made until the whole academy has met,” he said. The precise decision-making procedure is confidential and, according to Nobel practice, will only become public 50 years from now.
The laureates themselves were oblivious to the drama, however, with Bawendi saying he had been woken up by the academy. “I very surprised, shocked, sleepy and very honoured”, he said. “It’s a field with lots of people who have contributed to it from the beginning,” he added. “So I didn’t think it would be me that gets this prize. We’re all working together.”
Ekimov was reached by phone, while on a trip to Mexico, but Brus had not been reached by the time of the official announcement.
Quantum dots are nanoparticles so tiny that their size determines their properties. They are widely used in television screens, LED lamps and to guide surgeons removing tumour tissue.
In chemistry, the properties of a material are normally governed by its chemical makeup. But when material comes in nano-dimensions – as is the case with quantum dots – its size affects its colour and other properties.
This was known theoretically, but Ekimov made a crucial experimental demonstration while studying coloured glass. He observed that when glass was tinted with copper chloride, its colour varied depending on how long and how hot it was heated. X-ray imaging revealed this was because the manufacturing process affected the size of tiny crystals of copper chloride that had formed inside the glass. He published the discovery in 1981 in a Soviet scientific journal, but his research was not widely known to scientists on the other side of the iron curtain.
A few years later, Louis Brus was working at Bell Laboratories in the US, looking at using solar energy to drive chemical reactions of tiny cadmium sulphide particles floating in solution. He noticed that the optical properties of the particles changed after he left them on the lab bench for a while and guessed it was because the particles had grown. He also realised this was due to a size-dependent quantum effect.
In 1993, Moungi Bawendi revolutionised the methods for the chemical production of quantum dots, resulting in almost perfect particles whose size could be controlled. This high-quality production method paved the way for their wider commercial and medical application.
In a press briefing, the committee was asked about the choice to reward a Russian scientist, given Russia’s invasion of Ukraine. “When it comes to selecting the prize we simply follow the procedure of identifying the most important discoveries and identifying the most important contributors to those discoveries. Nationality doesn’t matter here. That’s in accordance with the will of Alfred Nobel.”
Prof Gill Reid, the president of the Royal Society of Chemistry said: “The recognition of this work on quantum dots is really exciting and shows how chemistry can be used to solve a range of challenges. These remarkable nanoparticles have huge potential to create smaller, faster, smarter devices, increasing the efficiency of solar panels and the brilliance of your TV screen.”
“Great science benefits from diverse viewpoints as part of a collective endeavour, and this year’s prize is a great example of that – people working in different labs, in different countries, approaching a problem from different angles,” she added.
“We don’t work in isolation in chemistry – teamwork is both a fundamentally important aspect of how science is actually done, and one of the most fun!”
