Why Are Quantum Dot Displays So Good?

What Is ‘Quantum Dot?’

Quantum dots are nano-sized crystals made of semiconductor materials. A nanometer (nm) is one billionth of a meter, which means these extra-small particles are smaller than 1/10,000 of a single strand of human hair.*

Quantum dots can be made of different kinds of elements, but when they’re regulated down to a size small enough, they possess physical properties that make them suitable for many different applications. For example, quantum dots are very efficient in absorbing and then emitting light. Based on this quality, quantum dots are being researched in areas such as solar panels, bioimaging, and, of course, display.

Why Are Quantum Dots Good For TVs?

<Quantum Dot Demonstration>

Quantum dots are photo-active; they absorb, and then emit light. And when they do, even if the dots are made of the same material, the light each dot emits is a specific colour (or wavelength) depending on the size of the core. For example, a quantum dot with a core of 2nm will emit a blue light while one with a 6~7nm core will emit red.

The colour of light each quantum dot gives off is also very stable and pure. Quantum dots can show precise colours while the light from conventional materials ends up getting mixed with adjacent colours. This is because the spectral line width (width of each peak in the graph below) of the light from quantum dots is much narrower than that from conventional materials.

As a result, the 3 primary colours can be more clearly distinguished in comparison to conventional TVs, which helps the quantum dot display show a wide range of colours more accurately.

Another advantage of these light-emitting quantum dots is that they’re very efficient. Compared to phosphors in conventional TVs, not only are they able to produce more colours, but the photo-active property allows for better light efficiency.

By leveraging this advantage, Samsung was able to jack up the peak brightness of its new SUHD TVs to 1,000 nits and higher, opposed to the previous 400 nits for conventional TVs– all the while further improving overall energy efficiency. Colours are perceived by light, and by offering more light along with more colours, Samsung SUHD TVs are great for HDR content.

What’s So Great About Samsung’s Quantum Dots?

Many previously developed quantum dots were based on materials that involve cadmium, such as cadmium sulfide (CdS) or selenide (CdSe). Although these quantum dots share the same advantages as written above, they hold a deadly threat against the environment as toxic Cd2+ ions may be released through nanoparticle degradation.

Samsung’s quantum dots, however, are cadmium-free. They’re based on indium (In) instead. After much research and development, Samsung is currently the only company that produces cadmium-free quantum dot displays. Samsung started focusing on quantum dots in 2001, and has since registered over 150 patents on the subject.

Samsung’s quantum dots are also durable. Being an inorganic compound, quantum dots are more resistant to oxidation than organic substances. Samsung also applies a quad-layer coat to its quantum dots to ensure the quantum dots are durable and kept stable over years of time. The result: a fantastic display that keeps its picture quality year after year.

For more information on Samsung’s SUHD TVs with Quantum Dot technology, please visit: www.samsung.com/global/tv/quantum-dot-display.

* Calculation based on assumption that an average human hair is about 100μm wide.