The 2023 Nobel prize in chemistry has been given to three developers of quantum dots – particles so small that their electrical and optical properties are influenced by quantum physics.
Two of the winners are Louis Brus at Columbia University and Alexei Ekimov at Nanocrystals Technology, both in New York, who discovered the technology in the 1980s while working separately. The third winner is Moungi Bawendi at the Massachusetts Institute of Technology in Boston, who developed better techniques for making the dots, which are also known as semiconductor nanocrystals.
The crystals are made from compounds such as lead sulphide or cadmium selenide and are only a few nanometres in size – or about one-thousandth the width of a human hair.
Because the crystals are so small, they have properties somewhere between individual atoms, which are governed by the laws of quantum physics, and ordinary larger pieces of material made from the same compounds.
Within quantum dots, electrons can only occupy discrete energy levels, which means that if excited, they emit light at specific wavelengths, depending on the properties of the crystal.
The dots are already being used to make lights, lasers and TV display screens, and are also being used in medical research, for instance to help image different structures within living tissues.
They are also being investigated as an aid to surgery for cancer because, if linked to targeting molecules and injected into someone with the condition, they home in on tumour cells and glow brightly, allowing only cancerous tissue to be removed during the operation.
The crystals may also be used to deliver toxic anti-cancer drugs only to the site of a tumour and to glow once they have dumped their cargo.
Speaking during a press conference on 4 October, Bawendi said: “I didn’t think it would be me that would get this prize. It’s a field with a lot of people that have contributed to it.”
The Nobel decision was leaked to a Swedish newspaper called Aftonbladet several hours before it was officially announced.