The Quantum Dot Story: Revolutionizing Electronics and Therapy
Breakthroughs in science don’t necessarily come with fancy packaging. Even when they are small, they can have a lot of potential. Let’s talk about quantum dots, the tiny particles that are quietly revolutionizing everything from electronics to medicine. In this piece, we’ll delve into the vivid world of quantum dots and examine how the work of Moungi G. Bawendi, Louis E. Brus, and Alexei I. Ekimov altered the course of science.
The Mystique of Quantum: Why Size Matters
Imagine living in a world where everything is extremely little. Gold rings take on a ruby red colour, while gold earrings abruptly turn blue. Why did the colors change? It’s all about scale and the mysterious quantum universe. The trio who won the Nobel Prize revealed this remarkable phenomena.
The Nobel Prize in Physics was awarded jointly to Moungi G. Bawendi from MIT, Louis E. Brus from Columbia University, and Alexei I. Ekimov from Nanocrystals Technology Inc. for their discovery of “quantum dots.” These are so minute particles that their special characteristics depend on their size. Their ground-breaking work created the framework for the broad range of applications of nanotechnology, from electronics to surgery.
In-depth Look at the Quantum World
The mysterious effects of the quantum realm are well understood. Herbert Fröhlich, a physicist, predicted that nanoparticles would act differently from their larger counterparts as early as 1937. Later, scientists proposed a number of size-dependent quantum phenomena.
The flow of electrons holds the key to understanding why size matters in nanoparticles. The flow of electrons and “holes” — spaces in the energy positions that earlier held electrons — determine the majority of a material’s physical attributes. Each material has a distinct feature called the “band gap,” which is altered when movement is constrained. Changes in a number of other attributes, including color, follow from this.
The effective dispersion of electrons and holes in ordinary materials is quite minimal, claims D D Sarma, a professor of chemistry at the Indian Institute of Science (IISc). The confinement effect occurs when you shrink a particle to a size that is comparable to these effective sizes. This causes a considerable shift in the electron and hole energies, altering the band gap and, as a result, the color as well as many other properties.
The Development of Quantum Dots
Quantum dots didn’t exist until the latter half of the 1970s. In the Soviet Union, Alexei I. Ekimov discovered a strange phenomenon involving glass combined with cadmium selenide and cadmium sulphide while working at the SI Vavilov State Optical Institute. This mixture would color glass either yellow or red depending on the heating and cooling. Yet why?
Ekimov made his discovery when he created copper chloride-tinted glass, X-rayed it, and discovered minute copper chloride crystals. The smaller these microscopic particles got, the more bluer light they absorbed. Ekimov published his findings in 1981 and this was the first time a size-dependent quantum effect had been observed.
In 1983, Louis E. Brus published his own findings behind the Iron Curtain. Brus discovered that cadmium sulphide particles’ optical properties changed after being neglected while he was working at Bell Laboratories in the US. He too noticed size-dependent optical characteristics when he produced smaller particles.
These nanoparticles, however, frequently had flaws and showed size fluctuations. After joining MIT, Moungi G. Bawendi, who began his postdoctoral training under Brus in 1988, developed the technique. His research team revolutionized the field in 1993 by creating simple procedures to create nearly faultless nanocrystals that displayed quantum phenomena.
The range of uses for quantum dots grew as research advanced. Electronics is one of the most well-liked applications for quantum dots. Mrinmoy De, an organic chemistry professor at IISc, claims that “on an LED screen, the color of the bright emissions depends on the unique photophysical properties of the quantum dots.” Quantum dots have also been applied to biological applications, including high-resolution cellular imaging, biological sensing, and possible therapeutics.