2023 Nobel Prize in Chemistry on quantum dots

 

The 2023 Nobel Prize in Chemistry - Honoring the Quantum Dot Revolutionaries

The Nobel Prize in Chemistry for 2023 has been awarded to three pioneers in the field of quantum dots - Moungi G. Bawendi, Louis E. Brus, and Alexei I. Ekimov. Their groundbreaking research discovered these fascinating nanoparticles and unlocked their potential applications across many fields.

But what exactly are quantum dots and why is this Nobel Prize so well-deserved? Let's dive in!

What are Quantum Dots?

Quantum dots are incredibly tiny nanocrystals, typically made of semiconductor materials like cadmium selenide. Just a few thousand atoms in size, their special electronic properties arise from the effects of quantum physics at this nano-scale.

When electrons in the quantum dot are energized, they jump to higher energy levels farther from the atom's nucleus before falling back down and releasing energy as light. The color of this emitted light depends on the size of the quantum dot - smaller dots emit blue light, while larger ones give off red. This phenomenon arises from quantum confinement effects within the nanocrystal.

Discovery and Development

While theorists had predicted the possibility of quantum size effects in small semiconductor particles since the 1930s, the physical realization remained challenging.

In the 1970s, Alexei Ekimov conducted early experiments showing color changes in nanometer-sized copper chloride crystals embedded in glass. This demonstrated the impact of size on their electronic behavior.

Around the same time, Louis Brus theoretically modeled and observed strong quantum confinement effects in cadmium sulfide nanocrystals suspended in fluids. This allowed tuning their light emission across the visible spectrum simply by changing the dot size.

But practical applications required high-quality quantum dots with precisely controlled properties. That's what Moungi Bawendi achieved in 1993, developing new chemical synthesis techniques to produce quantum dots with an incredible degree of control over size, shape, and surface chemistry.

Applications and Impact

Thanks to the foundational work by these three Laureates, quantum dots have now revolutionized diverse fields from TV displays to biomedical imaging.

Some of their key applications include:

• Displays - Quantum dot TV and phone screens provide extremely pure, bright colors from the size-tunable emission.
• LED lighting - Quantum dot lights are energy efficient and allow adjustable color temperature.
• Medical imaging - Fluorescent quantum dots light up cancerous tissues and help improve surgical accuracy.
• Photovoltaics - Quantum dot solar cells can harvest a broader spectrum of light energy from the sun.
• Sensing - When stimulated by light, quantum dots can detect specific target molecules useful for medical tests.
• 
  

The work of Ekimov, Brus and Bawendi has enabled the amazing potential of quantum dots to benefit society. It laid the bedrock for the bustling field of nanoscience and itself to the fundamental understanding of matter on the nano-scale.

By awarding them the Nobel Prize in Chemistry for 2023, the Nobel Foundation has recognized their revolutionary impact. The quantum dot genie is out of the bottle, and there's no going back!

Alexey Ivanovich Ekimov (born on 28 February 1945) is a Russian solid state physicist who discovered the semiconductor nanocrystals known as quantum dots, while working at the Vavilov State Optical Institute. He graduated from the Faculty of Physics, Leningrad State University. He obtained his PhD in 1974 from Ioffe Physical-Technical Institute, Saint Petersburg, Russia. He was awarded the 1975 USSR State Prize in Science and Engineering for the work on electron spin orientation in semiconductors. He is co-recipient of the 2006 R. W. Wood Prize of the Optical Society of America for "discovery of nanocrystal quantum dots and pioneering studies of their electronic and optical properties" shared with Alexander Efros and Louis E. Brus. Since 1999 Ekimov has been living and working in the United States as a scientist for Nanocrystals Technology, a company based in New York State, USA. [[https://en.wikipedia.org/wiki/Alexey_Ekimov]]

Louis Eugene Brus was born (10 August 1943) in Cleveland, Ohio, United States. During high

school in Roeland Park, Kansas, he developed an interest for chemistry and physics. He entered

Rice University in 1961 with a Naval Reserve Officers Training Corps (NROTC) college scholarship which required him to participate in NROTC activities at sea as a midshipman. He graduated in 1965 and moved to Columbia University for his PhD. For his dissertation, he worked on the photo-dissociation of sodium iodide vapor, under the supervision of Richard Bersohn. Upon obtaining his Ph.D. in 1969, Brus returned to the Navy as a lieutenant and served as a scientific staff officer in collaboration with Lin Ming-Chang, at the United States Naval Research Laboratory in Washington, D.C. Under the recommendation of Bersohn, Brus left the Navy permanently and joined AT&T Bell Laboratories in 1973, where he did the work that led to the discovery of quantum dots. In 1996, Brus left Bell Labs and joined the faculty in the Department of Chemistry at Columbia University New York, NY, USA where he is S. L. Mitchell Professor of Chemistry. He is the co-discoverer of the colloidal semi-conductor nanocrystals known as quantum dots. [[https://en.wikipedia.org/wiki/Louis_E._Brus]]

Moungi Gabriel Bawendi

was born (15 March 1961) in Paris, France, the son of Tunisian mathematician Mohammed Salah Baouendi. After periods living in France and Tunisia, Bawendi and his family migrated to the United States when he was a child. Bawendi graduated from West Lafayette Junior-Senior High School in 1978. He received his A.B. in 1982 from Harvard University and obtained his Ph.D. degree in chemistry in 1988 from the University

of Chicago, IL, USA under the supervision of Karl Freed and Takeshi Oka. Bawendi joined Massachusetts Institute of Technology (MIT) in 1990 and became professor in 1996. Bawendi

is a leading figure in research and development of colloidal quantum dots, and among the most cited chemists of the decade from 2000-2010. Bawendi is known for his advances in the chemical production of high-quality quantum dots.

[https://en.wikipedia.org/wiki/Moungi_Bawendi]

References: 

https://www.nobelprize.org/prizes/chemistry/2023/press-release/

https://en.wikipedia.org/wiki/Alexey_Ekimov

https://en.wikipedia.org/wiki/Louis_E._Brus

https://en.wikipedia.org/wiki/Moungi_Bawendi