The Nobel Prize Stories 3 – Magic of Colour Changing Dots Based of Size

October 9, 2023

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The Nobel Prize for chemistry is shared by three individuals Moungi Bawendi, Louis Brus and Alexei Ekimov for their independent work in the field. They were awarded for the discovery and synthesis of quantum dots. The dots that change the properties including colour based on their size and are the smallest components of nanotechnology.

What are these Quantum dots?

Quantum dots (QDs) can be thought of as “tiny crystals” that can glow in different colours when exposed to light. The colour they glow depends on their size – the smaller the size, the bluer the glow; the larger the size, the redder the glow.

Now, let’s use an analogy:

Imagine you have a box of clear gelatin (jelly). This clear gelatin represents the “glass matrix” or the material in which our QDs will be placed. Now, sprinkle some glitter (our QDs or tiny crystals) into this gelatin. When the gelatin sets, you have glitter embedded within it. Depending on the size of the glitter particles (our QDs), they will sparkle in different colours under a flashlight.

For clarity: Throughout this blog, we consistently use the metaphor of ‘glitters’ to represent Quantum dots, while the ‘gin’ stands for the medium or material where these Quantum dots reside, like glass, for instance.

Did you know?

Imagine if the “magic crystals” had a secret spell within them that only activated when they were tiny enough. That’s basically how quantum dots work. As these crystals become tinier, nearing the realm of the very, very small (nanoscale), the magic sparks inside (electrons) find themselves with less room to dance around. It’s like dancers on a stage that keeps shrinking. As the stage becomes too tight, the dancers have to change their routines. Similarly, as the quantum dots shrink, the electrons inside adjust their energy. This magical dance tweak influences how these crystals shimmer and shine when light touches them. Quite the magical phenomenon, right?

What is the importance of Quantum dots?

Imagine a “magic crystal” that not only sparkles but also has superpowers. These so-called “quantum dots” do more than just glitter. They can boost the efficiency of solar panels, capturing sunlight and converting it into energy. When added to the screens, like the one on your device, they make colours pop even more. And in medicine? These tiny wonders can light up things inside our bodies, helping doctors see better.

Simply put, think of quantum dots as tiny, multifaceted jewels. Scientists and innovators embed them into different tools and devices, giving them special capabilities.

The Journey of the Nobel laureates in the work of quantum dots

Alexei I. Ekimov

In 1981, Alexei I. Ekimov was like a chef who experimented by putting a specific type of glitter (copper chloride particles) into his gelatin (glass matrix). He noticed that by changing the size of these glitter particles, he could make the gelatin sparkle in different colours. This was a huge deal because it was a real-world example of how quantum effects can be seen in tiny particles.

Ekimov’s discovery led to numerous applications, and he even started a company to make and sell these special “glittering gelatins” (quantum dots in various materials). His work was so influential that he won a Nobel Prize in Chemistry in 2023 for it.

Louis E. Brus

Following Ekimov’s lead in making these “magic crystals,” Louis E. Brus took a step further in 1985. Imagine making these crystals in a way that they could swirl around freely in a liquid, like glitter in water. Brus did precisely that but with a specific type called cadmium sulphide nanoparticles. He then observed how they shine in this liquid and created a guide to explain why these tiny crystals change their sparkle based on their size.

Not stopping there, Brus dived deeper, exploring other magical materials – like sheets as thin as a single atom (graphene), tube-shaped carbon structures (carbon nanotubes), and another unique material named perovskites. He examined how these materials interact with light and tiny particles. He further clarified the magic behind the unique shine and behaviour of these quantum dots.

For his groundbreaking work and for bringing these tiny wonders into the limelight, Brus was honoured with the 2023 Nobel Prize in Chemistry.

Moungi G. Bawendi

In 1993, Moungi G. Bawendi took the world of these “magic crystals” by storm. Imagine being able to craft these crystals so they’re nearly perfect – each one almost identical in size and shape. That’s precisely what Bawendi accomplished. Using special ingredients called organometallic precursors, he crafted cadmium selenide nanoparticles. To ensure these tiny crystals grew uniformly, he added a sort of ‘magic potion’ known as surfactants. Bawendi also showcased a magical trick: by tweaking their size or what they were made of, he could change the colour of their sparkle.

Bawendi further refined the art of crafting these quantum dots, ensuring they were consistent, long-lasting, and versatile. He introduced a way to closely observe a single one of these crystals, revealing the secrets of their light. His advancements allowed these dots to shine in various applications, from high-tech lasers and lights to cutting-edge medical tools. He even ventured into using these magic crystals for ultra-modern communication methods.

For his exceptional craftsmanship and contributions to the realm of these glowing crystals, Bawendi was bestowed with the 2023 Nobel Prize in Chemistry.

Applause for the achievements

In conclusion, the 2023 Nobel Prize in Chemistry honoured three pioneering scientists for their groundbreaking work on quantum dots, a cornerstone of nanotechnology. These tiny “magic crystals” don’t just gleam in diverse colours based on their size but also showcase a range of enchanting properties, from sensitivity to magnetic fields to remarkable efficiency in their interactions.

Their applications are vast and transformative: powering vibrant displays in our gadgets, enhancing LED lights, charting biological mysteries, fostering innovations in electronics, boosting solar energy efficiency, and even paving the way for advanced quantum communication.

As we celebrate these trailblazing applications, we wholeheartedly applaud the scientists for their momentous achievements. Indeed, the wonders of quantum dots are shaping a brighter and more innovative future for us all.

Stay tuned for more science and technology updates, fun and much more.

References:

The Nobel Prize Stories 3 – Magic of Colour Changing Dots Based of Size

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