Quantum Dots: The Next Generation of Display Innovation

Quantum dots are ultra-fine semiconductor particles that are tens of thousands of times thinner than a human hair. Since inception, their physical characteristics that allow them to provide the highest level of color accuracy and brightness among existing materials had them positioned to revolutionize display technology.

When used in displays, quantum dots support a wide color gamut that closely matches colors perceived by the human eye and facilitate pixel-level light adjustment for more accurate black levels. Emitting light in all directions, quantum dots deliver uniform luminance and consistent color from any viewing angle while minimizing blue light exposure for a more comfortable viewing experience.

▲ SUHD TVs at CES 2015

What Sets Quantum Dot TVs Apart: Content, Film Quality and N-Cadmium Technology

The TV industry continues research and development into the commercialization of quantum dots as the material becomes a game-changer in display technology. For that reason, a variety of quantum dot TVs have hit the market recently — offering a wide range of options to customers.

However, key differences in quantum dot TVs lie in how the technology is implemented and the overall quality of the display. To ensure a premium viewing experience, factors such as the amount of quantum dot content, the quality of quantum dot film and the use of no-cadmium materials must be considered.

▲ Factors to consider when selecting a high-quality quantum dot TV

Quantum Dot Content

The true quality of a quantum dot TV is defined by its quantum dot content. The quantum dot film requires a minimum of 3,000 parts per million (ppm) of the material to achieve the vivid, rich picture quality and color expression that only quantum dots can deliver.

Quantum Dot Film

Samsung QLEDs eliminate the need for a phosphor layer, enhancing light and energy efficiency while delivering more vivid colors. A quantum dot OLED (QD-OLED), which consists of a thin-film transistor (TFT) layer,[1] a self-emitting light source and a quantum dot film that uses the light emitted from the light source, takes a step further enhancing picture quality. In either case, a dedicated quantum dot film that contains sufficient quantum dots is key in delivering top-class picture quality and longevity.

▲ A comparison of QD-OLED and LCD displays

No Cadmium

In the early stages of developing quantum dot TVs, cadmium was essential to achieving the key benefits of quantum dots such as color reproduction and contrast ratio. At the time, cadmium was considered the most efficient material for producing quantum dots.

However, cadmium’s toxicity became a significant obstacle to the commercialization of quantum dot technology. The element posed serious threats to the environment — making its widespread use difficult despite being the most suitable material for implementing quantum dot technology.

In response to this challenge, Samsung developed the no-cadmium quantum dot material in 2014 and successfully commercialized quantum dot technology with its SUHD TVs in the following year to open a new era of quantum dot TVs.

10 Years of Quantum Dot Innovation and Leadership

Samsung has quickly recognized the potential of quantum dot technology and led innovation in the global display market over the past decade through continuous research and investment.

▲ A timeline of Samsung’s quantum dot technology development from 2001 to 2022

Samsung began researching and developing quantum dot technology in 2001 — at a time when there was limited research on non-cadmium materials. Achieving vivid colors required making the nano-sized particles uniform, but the lack of technology and research made mass production extremely challenging.

Despite these obstacles, Samsung succeeded in creating a no-cadmium nanocrystal material in 2014. Since then, the company has accumulated extensive expertise — registering more than 150 patents — and continuously worked on advancing the technology. Samsung’s long-standing commitment culminated in 2015 when the company unveiled their first SUHD TVs with no-cadmium quantum dot technology.

▲ QLED TVs (75Q8C and 88Q8F) at Samsung’s First Look 2017 event during CES 2017

Samsung’s QLED lineup was revealed in 2017, setting a new standard for premium TVs that overcame the limitations of OLED TVs. By applying metal quantum dot technology, Samsung achieved the Digital Cinema Initiative’s color standard DCI-P3 and achieved 100% color volume for the first time in the world — thereby presenting unparalleled color expression. Notably, the use of inorganic quantum dot technology protected the screens from burn-in[2] to ensure consistent picture quality over time.

▲ (From left to right) Kwang-Hee Kim, Dr. Taehyung Kim, Dr, Eunjoo Jang, Sungwoo Kim and Seon-Myeong Choi from Samsung Advanced Institute of Technology

Following its success in developing a red light-emitting element for displays in 2019, the company enhanced the luminous efficiency of blue self-emitting QLEDs — considered the most challenging to implement among the three primary QLED colors[3] — to an industry-leading 20.2%.

“Discovering a blue material for self-emitting QLEDs and demonstrating industry-leading performance at the device level were significant achievements of this research,” said Dr. Eunjoo Chang, a fellow at Samsung Advanced Institute of Technology. “Samsung’s distinctive quantum dot technology has once again overcome technical barriers.”

These cutting-edge advancements led to the launch of the QD-OLED TVs, making history at CES 2022 by winning the Best of Innovation award for integrating quantum dot technology and OLED displays.

Samsung remains dedicated to advancing quantum dot technology through continuous innovation. The company continues to invest in leading display technology — from QLED to Neo OLED — by offering high brightness, color accuracy and frequency. Driven by Samsung’s unrivaled quantum dot innovations, the future of display technology is brighter than ever.

For more information, please visit: https://www.samsung.com/my/tvs/all-tvs/

[1] An electronic circuit that adjusts and controls the light-emitting layers

[2] Occurs when a static image is displayed for too long, causing color distortions or ghost images to remain on screen

[3] Red, green and blue

Since blue is known to be the most difficult color to implement out of the three primary QLED colors (red, blue and green), this achievement – coming in the wake of Samsung’s development of red QLED technology last November – once again proves Samsung’s excellence in the quantum dot technology sphere.

Blue Proves the Most Difficult of the Three Primary QLED Colors

Quantum dots (QDs) are semiconductor particles that measure a few nanometers in diameter (tens of thousands of times narrower than a single human hair). When illuminated, they re-emit light of a certain color depending on their size.

The blue QD, which has the largest band gap¹ among the three primary colors, rapidly oxidizes upon exposure to external light, resulting in a short lifespan and low luminous efficiency.² For this reason, up to now the industry had failed to develop even the technology required for blue quantum dot light-emitting diodes.

Overcoming Another Challenge by Developing Blue QLED Technology

But now, SAIT has successfully developed blue QLED technology, achieving industry-leading results such as 20.2% improved luminous efficiency, 88,900 nits of maximum luminance and 16,000 hours of QLED lifetime (measured at half-brightness for 100-nit luminance). These results were recorded in a study titled “Efficient and stable blue quantum dot light-emitting diode”, which was published by the journal Nature on October 14, 2020.

Eunjoo Jang, Samsung Fellow

“Samsung’s distinctive quantum dot technology has once again overcome the limitations of existing technology in the industry,” noted Dr. Eunjoo Jang, Samsung Fellow and corresponding author for the study. “I hope that this study goes on to help accelerate the commercialization of Quantum Dot light-emitting diodes (QLEDs).”

Quantum dots are made up of a basic structure of a core, a shell, and multiple ligands.³ In order to better stabilize the QD materials and secure durable photoresponse functionality, the researchers applied a structure with quantum dot double emitting layers and shorter ligands on the surface of the blue-light-emitting QDs while also improving current injection rates.

Taehyung Kim, Principal Researcher

Dr. Taehyung Kim, Principal Researcher and the first author of the study, said, “This research is meaningful in that we have not only established Quantum Dot light-emitting diode performance, but have also proven that the technology can deliver top-notch performance at the element level.”

(From left) Kwang-Hee Kim, Taehyung Kim, Eunjoo Jang, Sungwoo Kim, Seon-Myeong Choi from SAIT

¹ The difference of energy between the valence band of electrons and the conduction band.

² The ratio of the emitting luminous flux to the total input flux of source.

³ The core absorbs and re-emits light, while the shell layer surrounding the QD core improves lifespan and photoluminescence efficiency by preventing temperature/humidity-related damage. The branch-shaped ligands are located on the surface of the QD’s shell and help maintain inter-particle distance.