Honored for the discovery and synthesis of quantum dots The Nobel Prize in Chemistry goes to three nanoscientists This year’s Nobel Prize in Chemistry has been awarded to the three nanoscientists Professor Moungi G. Bawendi (MIT, Cambridge, MA, USA), Professor Louis E. Brus (Columbia University, New York, USA) and Dr. Alexei I. Ekimov (Nanocrystals - Technology Inc., New York, USA). Their research has paved the way for the applica tion of versatile nanocrystals known as quantum dots – that, like other nanostruc- tures, are subject to the rules of quantum mechanics. We interviewed Professor Jonathan de Roo from the Department of Chemistry at the University of Basel to 昀椀nd out more about these special nanocrystals and about the nanocrystal applications he is exploring in his research. SNI INSight: What are quantum dots and what’s so varying the size of the particles, it’s therefore possible to special about them? de昀椀ne the emission wavelength of quantum dots and, ac- cordingly, the energy or frequency of the light they emit. Jonathan de Roo: Quantum dots are colloidal — that is, 昀椀nely dispersed — semiconductor crystals that measure SNI INSight: How can this phenomenon be only a few nanometers in diameter. These tiny particles explained in simple terms? contain just a few hundred or thousand atoms, and their properties vary depending on their size. One such proper- Jonathan de Roo: If we expose a quantum dot to light, ty is their color when excited by exposure to light — for the electrons in the semiconductor material absorb ener- example, small quantum dots glow blue when excited gy and rise to a higher energy level. When they fall back with UV light, whereas medium-sized quantum dots emit to their original energy level, they give o昀昀 electromagnet- green light, and larger quantum dots emit red light. By ic waves in the form of light. The color of this light de- At the SNI’s Annual Event, Jonathan de Roo described his work with colloidal nanocrystals. SNI INSight December 2023 4