Russian physicist Alexei Ekimov invented the first quantum dots in 1977 while American chemist Louis E. Brus was the one who coined the term after discovering the same phenomenon of quantum confinement in colloidal solution in 1982. These materials are now used as the foundation for a category of electronic displays called quantum dot displays.
Sony became the first manufacturer to produce quantum dot displays with its commercial introduction of the Triluminous brand of television sets in 2013. Samsung Electronics followed with the introduction of its QLED brand of smart TV sets and computer monitors beginning in 2017 while also forming an alliance in the same year with Hisense Group and TCL Technology to produce and market quantum dot-enhanced display panels.
A particular quantum dot display is made up of a semiconducting nanocrystalline materials called a quantum dots that measure between two and ten nanometers. These materials are either photoluminescent or electroluminescent. All commercial quantum dot displays are based on photoluminescence while the electroluminescent variants remain experimental.
Photoluminescent quantum dots are photo-emissive. This means that they glow to a particular color after being illuminated with light. Electroluminescent quantum dots are electro-emissive materials that produce light and color in response to the passage of an electric current or strong electric field. Color production is specifically dependent on the size of a particular quantum dot. Larger ones produce reds and smaller ones produce blues.
The photoluminescent quantum dot displays in the market have occupied the higher-tier category of display panels. These products compete against other display technologies such as OLED or AMOLED and other LED-backlit liquid crystal display or LCD technologies such as in-plane switching or IPS LCD and virtual alignment or VA LCD.
Pros of QD Displays: What are the Advantages of Quantum Dot Displays?
The primary advantage of using quantum dots in display technology centers on their ability to produce pure monochromatic red, green, and blue colors. Take note that LED-backlit LCD panels are not efficient in producing saturated colors because of their dependence on white backlighting that produces a broad spectrum of visible light.
Panels made of quantum dots are more efficient. Each of these materials can produce a pure monochromatic color. The photoluminescent ones are also better at emitting pure basic colors upon excitement with a blue light. This results in an improved brightness and better color gamut due to the reduction of light losses and color cross-talk in color filters.
Another notable advantage of quantum dot display technology is that it is versatile. Specific quantum dot color filters have been used in the base LCD technology. Other manufacturers have also combined the benefits of the Mini-LED backlighting scheme with quantum dots. The same technology is also applicable to OLED and MicroLED technologies.
Below are the specific advantages of quantum dot display:
1. Ultra-High Definition Applications
A specific advantage of quantum dot displays is that they can produce a higher color gamut and more accurate color reproduction than conventional LCD panels. The specific color gamut of these displays is 40 percent to 50 percent higher than conventional LCD panels. Remember that quantum dots can emit a particular color depending on their size. Each of these materials can be fine-tuned to produce a specific and precise color within the visible light spectrum.
LCD panels that use this technology also outcompete LCD technologies such as VA LCD and IPS LCD and can rival OLED technology in terms of contrast ratio and viewing angle. The use of Mini-LED backlighting resolves the use of light leakage from traditional LED backlighting schemes while also providing better backlighting and local dimming control. This results in the production of deeper and more natural blacks and vibrant and brighter colors.
It is also worth mentioning that photoluminescent quantum dots also produce a brighter display output than OLED due to the addition of backlighting. The electroluminescent variants based on quantum-dot light-emitting diodes have general working principles similar to OLED and MicroLED panels. Each dot emits both actual light and color. This means native local dimming and individual pixel addressing with lengthier degradation than organic diodes.
2. Longer Lifespan and Energy Efficiency
A notable disadvantage of OLED is degradation. Organic light-emitting diodes degrade faster than inorganic light-emitting diodes and nanocrystalline materials. The different organic materials in an OLED also have different degradation rates. Blue-emitting diodes degrade faster than red-emitting and green-emitting diodes. This means that an OLED panel will develop more noticeable screen burns from the faster degradation rate of blue-emitting diodes.
Panels based on quantum dot technology have the advantage of having a longer lifespan than OLED display panels for the simplest reason that inorganic nanocrystalline materials do not degrade as fast as organic light-emitting diodes nor is the level of degradation is not as uneven as the different color-emitting organic diodes. These same materials are also less susceptible to damage due to water exposure, unlike the more delicate organic materials.
Another advantage of quantum dot displays is energy efficiency. The specific displays equipped with Mini-LED backlighting can consume 20 to 50 percent less power than conventional LCD panels because of better backlighting and local dimming control. Another reason for this energy efficiency comes from the size of the nanocrystalline materials that allow them to produce 30 percent brighter and more vibrant colors than conventional LCD panels.
3. Wider and Promising Future Applications
Remember that most commercial quantum dot displays in the market are technically LCD panels that use nanocrystalline materials instead of the traditional and larger crystalline materials. The addition of Mini-LED backlighting makes these quantum dot LCD panels comparable to OLED and MicroLED panels in terms of contrast ratio and viewing angle while also enabling them to produce more accurate colors and vibrant images than conventional LCD panels.
The technology is also versatile because it can be integrated with other display technologies. Manufacturers such as Samsung and TCL have been working on commercializing OLED panels made of nano-sized organic light-emitting diodes. These are called QD-OLED. There is also ongoing research on producing nano-sized inorganic LEDs called quantum dot nanorod emitting diodes and the resulting products are called QDNED display panels.
Another promising application of quantum dot technology is in the development of specific electroluminescent or self-emissive displays. This involves using electroluminescent quantum dots that function as quantum-dot-based light-emitting diodes or QD-LEDs arranged in either a passive matrix or active matrix array similar to the structural design of OLED panels and an improvement in the capabilities and advantages of MicroLED panels.
Cons of QD Displays: What are the Disadvantages of Quantum Dot Display?
It is important to reiterate the fact that quantum dot displays are either photoluminescent or electroluminescent. The current products in the market are based on photoluminescence. These displays use quantum dots to produce colors through exposure to a light source and use backlighting to make these colors visible or displayable.
Electroluminescent quantum dot displays are more promising but are still experimental. It is possible for them to be available in the mass market soon following the introduction of prototypes from companies such as Samsung. These variants use quantum dots that produce light and color in response to the passage of an electric current or strong electric field.
Nevertheless, with photoluminescent or electroluminescent quantum dot displays in the market, it is possible for confusion to arise. Some of the notable advantages of quantum dot displays are unique to the photoluminescence variant. The same is true for the electroluminescent variants which have a certain edge over their photoluminescence counterparts.
Below are the specific disadvantages of quantum dot displays:
1. A quantum dot display is an ambiguous category of electronic display panels because of the different variations in the implementations of quantum dot technology and the existence of the general photoluminescent and electroluminescent variants.
2. LCD panels based on this technology will have a slower native pixel response time than OLED panels. Manufacturers have integrated these panels with microprocessors for hardware calibration purposes and specific image and video processing.
3. Another disadvantage of a quantum-dot LCD panel is that it inherits the inherent drawbacks of LCD technology. These include contrast ratio, viewing angle, and energy efficiency rating that cannot compete against panels based on OLED technology.
4. The same is true for OLED panels enhanced with quantum dots. The nano-sized organic diodes would also be susceptible to uneven degradation and shorter overall lifespan as evident from the emergence of screen burns and higher susceptibility to water damage.
5. It is also worth noting that another drawback of quantum dot displays is their higher cost and price compared to conventional LCD and OLED panels. These come from the complex manufacturing and the use of rare earth metals for material synthesis.