Earlier on Wednesday, the academy appeared to have inadvertently published the names of the three scientists it said had won this year’s Nobel Prize in chemistry.

Bawendi is a professor at the Massachusetts Institute of Technology (MIT), Brus is professor emeritus at Columbia University and Ekimov works for Nanocrystals Technology Inc.

Brus was hired by AT&T Bell Labs in 1972 where he spent 23 years, devoting much of the time to studying nanocrystals.

Bawendi was born in Paris and grew up in France, Tunisia, and the US Bawendi did his postdoctoral research under Brus then joined MIT in 1990 and became professor in 1996.

Ekimov was born in the Soviet Union worked for the Vavilov State Optical Institute before moving to the United States. In 1999, Ekimov was named chief scientist at Nanocrystals Technology Inc.

Usually the names of the winners are a well-kept secret, but public broadcaster SVT said the academy sent a press release by mistake early on Wednesday that contained the names of the winners.

The press release said the prize went to three US-based scientists for the “discovery and synthesis of quantum dots,” according to SVT.

Swedish newspaper Aftonbladet published a copy of an email it said was from the academy naming the laureates.

The Swedish Royal Academy of Sciences apologised for the mistake.

“This is of course very unfortunate. We deeply regret what happened,” Hans Ellegren, Secretary General of the Royal Swedish Academy of Sciences, told a press conference.

However, Bawendi told reporters he had not heard the news before receiving the call from the Nobel Committee.

“I didn’t know, I was awakened by the Swedish Academy. I was sound asleep,” he said via telephone during a press conference, noting it he had not expected the call.

Bawendi listed his feelings as “very surprised. Sleepy, shocked. Unexpected and very honoured.”

Nobel leaks are rare, with the various prize-awarding academies going to great lengths to keep the winners’ names under wraps until the announcements.

The list of nominations for each prize is also kept secret for 50 years.

The Chemistry Prize is the third Nobel award announced in Stockholm, Sweden, this week.

On Monday, the Medicine Prize went to Katalin Kariko and Drew Weissman for work on messenger RNA (mRNA) technology that paved the way for groundbreaking Covid-19 vaccines.

On Tuesday, the Physics Prize was given to Pierre Agostini, Ferenc Krausz and Anne L’Huillier for research developing ultra quick light flashes that make it possible to study electrons inside atoms and molecules.

Except for Economics, the prizes were endowed by Swedish industrialist Alfred Nobel, the inventor of dynamite.

The first awards were handed out in 1901, five years after Nobel’s death.

Each prize is worth 11 million kronor (US$1 million) and will be handed out with a diploma and gold medal on December 10 – the date of Nobel’s death in 1896.

Last year, the Chemistry Prize went to the Americans Barry Sharpless and Carolyn Bertozzi and Danish scientist Morten Meldal, who were awarded the prize for the development of methods for the targeted assembly of molecules.

The highly watched Literature and Peace Prizes to be announced on Thursday and Friday.

The Economics Prize closes out the 2023 Nobel season on Monday.

Reporting by Associated Press, Agence France-Presse, Reuters