These are “nanoparticles with unique properties”, for example for screen technologies and LED lamps or for illuminating tumor tissue, as the Royal Swedish Academy of Sciences explained the decision.
Quantum dots consist of a few thousand atoms that collectively behave like an artificial “macroatom”. These are structures only a few nanometers in size with “caged” electrons, with different energy levels for the electrons. The three Nobel Prize laureates in chemistry had successfully created quantum dots and thus small particles whose properties are determined by quantum phenomena – with today “great relevance for nanotechnology,” said the statement, which was published in the media before the official announcement on Wednesday morning circulated.
The chairman of the Nobel Prize Committee for Chemistry, Johan Åqvist, explained that the central property of quantum dots is that their color changes as their size increases. While small dots appear bluish, this shifts towards red as their size increases. This means we are dealing with a “new class of materials” in which, for the first time, properties can be specifically changed while maintaining the same basic chemical composition, explained physicist Heiner Linke during the announcement.
Image: APA/AFP/JONATHAN NACKSTRAND
The change in color is a “quantum mechanical effect” that is based on the fact that in smaller quantum dots there are fewer electrons to divide the energy between. The more energy, the bluer the quantum dot emits. In theory, such structures were predicted as early as the 1930s. “But it took five decades to realize it,” says Linke.
They were first observed by Yekimow in glass and Brus in the form of free-flowing particles in liquid. Both already described the color change with size. However, for around ten years it was thought that the size could not be controlled with sufficient precision. This then changed with the work of Bawendi, who developed a method to control the growth process of the particles by controlling heat.
“That brought opportunities for commercial applications,” said Linke, who brought up QLED screens or medical applications. The quantum dots, in which the electrical or magnetic properties or even the melting point can be adjusted, so to speak, also have potential for producing photons for quantum communication – a direction that is being pursued in Austria, for example – or in catalysis processes.
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World mirror
Embarrassing: Nobel Prize winner for chemistry accidentally leaked
STOCKHOLM. According to Swedish media reports, this year’s selected Nobel Prize winners in chemistry may have accidentally…
Embarrassing: Nobel Prize winner for chemistry accidentally leaked
Paris-born Bawendi, who works at the Massachusetts Institute of Technology (MIT) in Cambridge, said his initial reaction at the press conference was “very surprised, sleepy, shocked and very honored.” However, he was not informed in advance by the previously leaked information about this year’s prize winners. He was woken up with a call from the Swedish Academy. “I didn’t think I could get the prize,” said Bawendi.
Co-Nobel Prize laureate Brus works at New York’s Columbia University; his work “as a pioneer for quantum dots” was honored with a highly endowed Kavli Prize in 2008. The Russian researcher Yekimov, who is also considered a discoverer of colloidal semiconductor nanocrystals, now works at the New York company Nanocrystals Technology Inc.
This year the award is endowed with eleven million Swedish crowns (around 930,000 euros), one million crowns more than last year. The prize is traditionally presented on December 10th, the anniversary of the death of the founder Alfred Nobel.
Last year the award went to the two US researchers Carolyn R. Bertozzi and Barry Sharpless and their Danish colleague Morten Meldal. They were recognized “for the development of click chemistry and bioorthogonal chemistry,” and for the academy an “ingenious tool for building molecules.” For Sharpless it was the second Nobel Prize in Chemistry after 2001.
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