Moungi Bawendi

Moungi BawendiMoungi Bawendi, one of three winners of the 2023 Nobel Prize for Chemistry, in front of tubes with quantum dots, which when illuminated with ultraviolet light, the dots fluoresce brightly in a range of colors determined by the sizes of the particles.

Moungi Bawendi (born 1961, Paris, France) is a French-born American chemist who was awarded the 2023 Nobel Prize for Chemistry for his work in producing quantum dots, which are very small particles whose unusual quantum properties depend on their size. He shared the prize with Russian-born American physicist Alexei Ekimov and American physical chemist Louis Brus.

Bawendi’s mother was Hélène Baouendi, and his father was renowned mathematician Mohammed Salah Baouendi. He grew up in France, Tunisia, and the United States, where his father joined the mathematics faculty first at Purdue University and then at the University of California, San Diego.

Bawendi earned a bachelor’s degree in 1982 and a master’s degree in 1983 from Harvard University. He attended the University of Chicago for graduate studies and received a Ph.D. degree in 1988. He subsequently joined Bell Laboratories as a postdoctoral fellow. There he worked under the guidance of Brus, researching photo-physics and basic concepts in materials synthesis that were fundamental to advancing methods of producing high-quality nanoparticles and quantum dots. In 1990 Bawendi accepted a position at MIT (Massachusetts Institute of Technology), where he later became a full professor in chemistry (1996).

Since the 1930s, physicists and chemists have known that a material’s size has a significant effect on its properties; that is, in particles of matter a few nanometers in size (1 nanometer = 10−9 meter, or a billionth of a meter), quantum mechanical effects become significant. It is particles of this size that are called nanoparticles.

In the early 1980s Ekimov and Brus independently produced quantum dots, nanoparticles that had different properties, depending on their size. In the late 1980s, when Bawendi was a postdoctoral fellow in Brus’s laboratory, the methods used to produce quantum dots unfortunately produced dots of varying quality and size.

At MIT in 1993 Bawendi and his collaborators concentrated their efforts on forming high-quality cadmium selenide (CdSe) quantum dots. They injected material that would form CdSe crystals into a hot solvent. Small crystals formed, but the injection cooled the solvent and the crystals stopped growing. By increasing the temperature of the solvent, the crystals started to grow again, and they grew with a consistent structure and shape. Bawendi and his group could then precipitate dots of a specific size out of the solution.

The Bawendi method of making quantum dots was easy and thus led to an explosion of work in quantum dots. Today quantum dots are used in many applications, including in QLED (quantum-dot light-emitting diode) screens, in solar cells, and as markers in biomedical imaging.

Erik Gregersen Kara Rogers