What is quantum dot technology?

Quantum dots are making waves in the world of TVs and monitors, but what are they exactly? Is this another abuse of the word “quantum” by marketers, or are these points as amazing as they say?

The artificial atom

Quantum dots are particles of semiconductor material that are only a few nanometers in size. Also called “artificial atoms” (although they are much larger than one atom), these points act in the same way as atoms in their relationship to electrons. They are so small that their electrons are “trapped” and behave in the same way as atoms. When UV light hits a quantum dot, its electrons go into a higher energy state. When the electrons fall back to their base level, the energy difference between the two states is released as light.

They are called “quantum dots” for two reasons. First, they exhibit quantum properties through the way they limit electrons in them. Quantum effects are the physical subatomic laws that scientists are still trying to fully understand, but we can already apply them in devices like quantum computers.

They are called points because they are so small that they are practically zero-dimensional. In other words, they are a single point without width, length or height. Well, okay, they are a few dozen atoms in diameter, but they are so close to being zero-dimensional points that the crazy laws of quantum mechanics set in.

Why are quantum dots so useful?

Quantum dots behave like atoms that have been excited, but they differ in a fundamental respect. The light you get from an atom or quantum dot is equal to the amount of energy absorbed and released, which determines the wavelength and therefore the color of the light. However, one type of atom (eg iron or sodium) will always emit the same color wavelength.

Quantum dots, on the other hand, can all be made of the same semiconductor material, but produce different wavelengths depending on their size. The larger the dot, the longer the wavelength and vice versa. The large dots thus tend towards the red end of the spectrum and the small ones towards the blue end.

This property of quantum dots means that you can precisely control the emission of colored light to achieve vibrant and accurate colors.

Quantum dots have a precise structure because they are crystals. The silicon wafers that our chips are made of are also crystals that organize themselves into atomic patterns. That is why we can produce quantum dots with precise nanoscale structures. If we were to build them atom by atom, they would not be very practical!

They can be made by radiating atoms on a substrate to build crystals, by radiating ions (free electrons) on your semiconductor substrate or by using X-rays. Quantum dots can also be created using X-rays. Quantum dots can also be created using chemical and even biological processes. However, research into biological production is still in its infancy.

Where are quantum dots used?

Outside of the QD-OLED and QLED screens that most people are familiar with, there are many applications for these invisible dots in many different technologies.

Solar panels are a great potential use of quantum dots. The current silicon-based solar cells are already quite efficient at capturing energy from light, but because quantum dots can be ‘tuned’ to absorb light from different parts of the electromagnetic spectrum, they can give rise to solar panels, much more efficient. Not only would these panels be more efficient, but they would also be cheaper to produce as the process of making the necessary quantum dots is relatively simple.
In theory, it is possible to make a solar cell with pure quantum dots, but these can also be used in hybrid solar cells. Increase the efficiency of other solar energy technologies.

Quantum dots can be used in photon detectors, have exciting potential in biomedicine and can even make it possible to make much cheaper and more efficient LEDs.

An interesting use of quantum dots is in cancer treatment, where the dots are designed to accumulate in specifically targeted organs to release anti-cancer drugs as well as advanced imaging. They may even play a role in the early diagnosis of tumors.

Quantum dots could also hold the key to photonic computing, as electrical circuits become so small that quantum effects make it impossible for electrons to pass through. Quantum dots can solve many of the problems that photonic data processing still faces.

The quantum defies the imagination

Richard Feynman, the famous American physicist, often said something like “If you think you understand quantum mechanics, you do not understand it”. Albert Einstein is also known for not venturing there. So we’m pretty comfortable admitting that we do not really understand quantum dots.

What we do know is that they are very versatile and will enable amazing technological innovations, in addition to making nicer computer screens. So the next time you wonder about the life of your QLED TV, think for a moment about the incredible subatomic magic that happens so you can get a better picture and how quantum dots can one day perform important functions in your body and in the world.

Leave a Comment