Kate Vasey, Staff

This past week, the Nobel Prize Committee awarded those whose work has substantially benefited humankind in the past year. The laureates in chemistry this year are three scientists who worked toward the discovery and synthesis of quantum dots. Alexei Ekimov, Luis Brusand Moungi Bawendi played different parts in the discovery and popularity of these nanostructures.

Despite its sci-fi-esque name, quantum dots can be described as very small crystal structures. So small that if the quantum dots were lined along a baseball bat, there would be approximately half a billion quantum dots in that single line. The fun begins when shining ultraviolet light on the dots, which fluoresce in vivid colors. The excitement around quantum dots comes from the fact that as they grow in size, the crystals change in color. This is like having a pile of salt that changes color as more salt is added (and it’s glowing)! Scientists can choose what colors they want to see by changing the size of the dots.

The vibrant color of the dots has versatile applications in LED displays, where the dots act as pixels and color filters. Many companies are already using quantum dots in their displays, which can be spotted by looking for a “Q” in the name of the product.

Researchers are also studying the use of quantum dots in photovoltaics or solar cells. The dots offer a cheaper alternative to energy capture compared to current materials like silicon, cadmium and telluride.

For biomedical applications, quantum dots can be used in imaging technology that allows scientists to track the movement of drugs through the body or a single cell. Their small size and bright glow make them easy to spot as they are metabolized.

In 1979, Ekimov was researching what gave stained glass its unique color, and why changing the temperature during the glass-blowing process resulted in different colors of the same material. He found that some materials changed color based on their size; they were quantum dots! Independent of this observation, Brus found the same occurrence happening in a different material in 1982. Both concluded that the nanocrystals were so small that they behaved differently than expected, called the quantum size effect.

In 1993, Bawendi created a new way to synthesize the quantum dots that involved the sudden injection of an ingredient of quantum dots into a boiling solution. By controlling the temperature of the solution, Bawendi could control the size of the nanoparticles. This new method greatly decreased the effort needed to synthesize quantum dots and increased the yield.

Nanoparticle research is a burgeoning and promising field of chemistry because of the wide range of applications and how much is still yet to be discovered. Quantum dots are just the tip of the nanoparticle iceberg, with more being learned about them daily. Their small size allows scientists to push the envelope of innovation and research and advance many other branches of science. The 2023 Nobel Prize in chemistry displays the importance of continued work in nanoparticles.