GS Paper 3
Syllabus: Science and Technology
Context: The 2023 Nobel Prize in Chemistry was awarded for the discovery and synthesis of quantum dotstiny particles with unique optical properties due to their small size.
What are Quantum Dots?
Quantum dots are tiny particles, just a few nanometers in sizewith unique optical properties due to their small size. While their atomic structure is the same as bulk materials, quantum dots’ properties can be altered by adjusting their size.
At the nanoscale, these particles exhibit size-dependent characteristics influenced by quantum forces, which differ from macroscopic physics governed by gravity.
Physicists in the 1970s discovered that adding elements like gold, silver, cadmium, sulphur, or selenium could modify the optical properties of glass, but the synthesis of quantum dots had not yet been achieved.
Contributions of the scientists:
| Scientist | Contribution to Quantum Dots |
| Dr Alexei I Ekimov | In the early 1980s, Dr Ekimov pioneered the creation of size-dependent quantum effects in coloured glass. He conducted research on glasses tinted with copper chloride, which, when heated and cooled under different conditions, resulted in glass with varying light-absorbing properties due to the formation of differently sized copper chloride crystals. |
| Dr Louis E Bruce | In 1983, Dr. Brus and his colleagues took a significant step by producing similar crystals in a liquid solution instead of glass. This innovation allowed for more precise manipulation and study of the crystals |
| Dr Moungi G Bawendi | Dr. Bawendi and his team, in 1993, developed a technique to create well-defined quantum dots with high optical quality. Their process involved injecting a substance into a heated solvent and adjusting the temperature to control the size of nanocrystals. The resulting quantum dots had a smooth exterior surfacemaking them suitable for a wide range of applications |
Who are the three scientists?
- Alexei Ekimov: Born in 1945 in the former USSR, he obtained his PhD in 1974 from Ioffe Physical-Technical Institute, Saint Petersburg, Russia. He served as the Chief Scientist at Nanocrystals Technology Inc., New York, USA.
- Louis Brus: Born in 1943 in Cleveland, USA, he earned his PhD in 1969 from Columbia University, New York, where he is a professor.
- Moungi Bawendi: Born in 1961 in Paris, he grew up in France, Tunisia, and the US. He currently holds a professorship at the Massachusetts Institute of Technology (MIT), USA.
Applications of Quantum dots:
| Application | Description | Examples |
| Display Technology | Enhance display quality in QLED screens. | Samsung QLED TVs |
| Lighting | Adjust the colour temperature in LED lamps. | Nanoco LED lighting solutions |
| Biomedical Imaging | Map cells and organs for research and diagnostics. | Quantum dots for cancer imaging |
| Drug Delivery | Targeted drug delivery for therapy. | Quantum dots for drug delivery |
| Photovoltaics | Improve solar cell efficiency. | Quantum dot solar cells |
| Sensing and Detection | Detect and measure specific substances. | Quantum dot sensors |
| Quantum Computing | Quantum bits (qubits) in quantum computing. | Quantum dot-based qubits |
| Security Marking | Anti-counterfeit markers on currency and documents. | Security applications |
About Quantum Computing:
Insta links:
Prelims Links:
Which one of the following is the context in which the term “qubit” is mentioned? (USPC 2022)
(a) Cloud Services
(b) Quantum Computing
(c) Visible Light Communication Technologies
(d) Wireless Communication Technologies
