This year’s Nobel Prize was awarded to three scientists for “the discovery and synthesis of quantum dots”, nanoparticles with versatile properties that could be useful for color displays, biological imaging, solar panels, and many other current and potential applications in diverse fields of technology.

Quantum dots are “ultrasmall” nanoparticles on a scale of 1.5 to 10 nanometers in size. For very small particles, the properties of the particles can depend on their sizes, an idea pioneered by Herbert Fröhlich in 1937. Quantum dots, which are also known as artificial atoms, confine electrons within their structure; as the electrons are confined into smaller spaces, they emit photons, particles of light, at different wavelengths. This effectively means that changing the size of a quantum dot can change the optical characteristics of the dot, such as color.

Few believed that it was possible to actually construct such nanoparticles. However, in 1981, Alexey Ekimov and his team chemically synthesized quantum dots made out of cadmium selenide, and they observed the unusual optical properties that were predicted. A few years later, Louis Brus found color-changing properties in nanoparticles that floated freely in liquid. 

Then, in 1993, the chemist Moungi Bawendi proposed a new technique for producing quantum dots. He used a method called colloidal synthesis, in which one could dissolve metal ions in a solvent and treat the solution to create quantum dots. This method allowed scientists to create quantum dots of varying sizes with ease. In this way, one could tune the sizes, and therefore the unique properties, of quantum dots. The Nobel Prize was awarded to Bawendi, Brus, and Ekimov.

Because quantum dots are so configurable, they are useful for everything from bioimaging and drug delivery to photovoltaic solar cells, displays, and cameras. As one example of an experimental technology using quantum dots, take the memristor, a hypothetical memory device that could store memory based on the resistance of a material and could be based on quantum dots. They could also be applied in biomedicine, where they are becoming substitutes for organic dyes.

These are merely a few examples of the present and future uses of quantum dots. Their sheer versatility makes them — and the scientists who discovered them — worthy of a Nobel prize.