Swedish newspaper Aftonbladet published a copy of an email its said was from the academy naming the laureates as Moungi G Bawendi, Louis E Brus and Alexei I Ekimov.
"The Nobel Prize in Chemistry in 2023 rewards the discovery and development of quantum dots, nanoparticles that are so small that their size determines their properties," Dagens Nyheter (DN), another Swedish daily, quoted an email from the academy as saying.
But Johan Aqvist, chair of the academy's Nobel committee for chemistry, told Reuters: "It is a mistake by the Royal Swedish Academy of Sciences. Our meeting starts at 9.30am CET (6.30pm AEDT) so no decision has been made yet. The winners have not been selected."
The announcement of this year's Nobel prize for chemistry is due at 11.45am CET (8.45pm AEDT).
Nanoparticles and quantum dots are used in LED-lights and TV-screens and can also be used to guide surgeons while removing cancer tissue, among other things, according to the statement.
Bawendi is a professor at the Massachusetts Institute of Technology, Brus is professor emeritus at Columbia University and Ekimov works for Nanocrystals Technology Inc.
The more than century-old prize is awarded by the Royal Swedish Academy of Sciences and is worth 11 million Swedish crowns ($A1.57m).
