In this blog post, we’ll explore the advancements in nanotechnology, the principles and features of Quantum Dot (QD) display technology, and its current and future potential.

QD Technology: A Focus for Samsung Electronics and LG Electronics

Samsung Electronics and LG Electronics have long been engaged in fierce competition in the global TV market. At “IFA 2016,” Europe’s largest consumer electronics trade show held in Germany, Samsung Electronics garnered significant attention by unveiling its SUHD TV featuring Quantum Dots (QD) technology. At the time, Samsung Electronics also presented a vision to focus on QD technology for the next 10 years.
At that time, the QD technology market was projected to grow from 1.7 million units in 2015 to 14.6 million units by 2020; however, QD technology has now surpassed these initial projections and established itself as one of the core technologies in the premium TV market. Global companies, including Samsung Electronics, have continuously advanced QD technology, and it is recognized as a crucial technology in the display industry. So, what is it about QD technology that has generated such high expectations?

Nanotechnology and the Principles of Quantum Dots

To understand QD technology, we must first examine nanotechnology. Just as the 20th century was the era of microtechnology, the 21st century is often referred to as the era of nanotechnology, highlighting the vital role nanotechnology plays across various industries. The term “nano” is derived from the Greek word “nanos,” meaning one-billionth. Nanotechnology refers to technology that operates at the nanometer (nm) scale. Through highly precise processes, it enables the production of materials with high-performance and low-power characteristics, and by integrating various fields such as physics, materials science, and electrical engineering, it can create new technologies.
The QD technology mentioned earlier also emerged based on these advancements in nanotechnology. A quantum dot (QD) generally refers to a semiconductor nanoparticle ranging in size from a few to tens of nanometers. Because quantum dots can produce a variety of colors by adjusting their particle size, they are currently being utilized in various fields, including the display industry.
To understand quantum dots, one must first grasp the concept of energy bands. The energy levels that electrons can occupy within an atom are fixed. However, when multiple atoms are packed very closely together—as in the interior of a crystalline material—the energies that electrons can occupy form a specific range, known as an energy band.
When the size of a specific inorganic compound is in the range of a few to tens of nanometers, energy bands also form. These bands are divided into a lower energy band (low energy level), where most electrons reside, and an upper energy band (high energy level), where almost no electrons exist.
Quantum dots alter the gap between these two energy bands by controlling the particle size. For an electron to move from the lower energy band to the upper energy band, it must absorb energy equal to the energy difference between the two bands; this is called selective energy absorption. Conversely, when an electron moves from the upper energy band to the lower energy band, it emits energy equal to that difference. The energy emitted at this time takes the form of electromagnetic waves—that is, light.
Since the wavelength of light is inversely proportional to its energy, even within the same material, different colors can be produced depending on the particle size. Generally, as quantum dot particles become larger, the wavelength of the emitted light becomes longer.
The optical characteristics of quantum dots include higher color purity and superior light stability compared to conventional light-emitting materials. Furthermore, because they are nanoparticles, research is underway to utilize them as fluorescent materials by binding them to substances such as DNA.
Above all, the most significant characteristic is that the spectrum of the emitted light varies not according to the type of particle, but according to its size.
While conventional light-emitting diodes (LEDs) emit light at only a specific wavelength, quantum dots can achieve a wide color gamut simply by adjusting their size. This characteristic has attracted attention in the display industry, and subsequently, global companies have begun competing in earnest to develop QD technology.

Structure and Characteristics of QD Displays

Quantum Dot Displays are commonly referred to as QD displays. The operating mechanisms of quantum dots are broadly categorized into two types: photoluminescence (PL), in which quantum dots absorb external light and re-emit it as light, and electroluminescence (EL), in which they emit light on their own when an electric current is applied.
Most commercially available QD TVs currently use QDEF (Quantum Dot Enhancement Film), one of the PL methods. This method involves adding a quantum dot film to the existing LCD structure by inserting a film containing quantum dot particles over the backlight unit (BLU). Here, “LCD” refers to a standard liquid crystal display, and the BLU serves as the light source. Light emitted from the backlight passes through the quantum dot film to produce purer colors, and then passes through the liquid crystal and color filter to produce the final image.
Meanwhile, the display industry continues to conduct research with the ultimate goal of developing QD-LEDs based on the electroluminescence (EL) method. However, most products currently sold under the name “QLED TV” are LCD-based displays using QDEF, not self-emissive QD-LEDs. True self-emissive QD-LEDs are a next-generation technology featuring a structure in which RGB subpixels composed of quantum dots each emit light directly when an electric current is applied, and active research and development in this area continues today.
Theoretically, self-emissive QD-LEDs are expected to offer advantages such as excellent color reproduction, a wide color gamut, high energy efficiency, and a long lifespan. For these reasons, display companies around the world are continuously investing in the development of self-emissive QD-LEDs as a next-generation display technology.

The Present and Future of QD Technology

However, despite its advantages—such as excellent color reproduction, a wide color gamut, and a long lifespan—QD technology, which is expected to bring new changes to the display industry, still faces numerous challenges that need to be addressed. In particular, for self-emissive QD-LEDs using the field-emission method, ensuring stable luminous efficiency and lifespan during mass production remains a critical technical challenge. Furthermore, ongoing research is being conducted on long-term reliability and degradation characteristics.
Furthermore, while currently commercialized QD-LCDs demonstrate excellent performance in terms of brightness and color gamut, self-emissive OLEDs maintain their strengths in certain characteristics such as contrast ratio, viewing angle, and response speed. Consequently, display technologies continue to compete in different markets based on their respective strengths and weaknesses.
Nevertheless, the outlook for quantum dot displays remains bright. Global companies are continuously investing in the development of quantum dot technology, and the related market is growing steadily. Once technical challenges are resolved, expansion into a variety of products is expected to accelerate even further.
Above all, the scope of application for QD displays is expanding beyond TVs to include smartphones, tablet PCs, monitors, laptops, automotive displays, and wearable devices. Recently, research into the application of quantum dot technology has been actively underway in various industries beyond displays, including medical imaging, lighting, and optical sensors.
Whether quantum dot display technology will indeed establish itself as a core technology in the future display industry depends on continued technological advancements and market changes. What is certain is that quantum dot technology is positioning itself as a key pillar of the display industry and will continue to evolve steadily in the future.