Illustration of the US physical chemist Louis Brus (born 1943). Brus is best known for the discovery of quantum dots, which are nanoparticles of semiconductor material that emit photons when excited. The size of the quantum dot changes the wavelength of photon emitted, and therefore the colour. Brus was awarded a share of the 2023 Noble Prize in Chemistry along with his colleague Moungi Bawendi and Alexei Ekimov (who discovered quantum dots independently of Brus and Bawendi) for this discovery.