Illuminating the Future: Exploring QLED Technology

By Ankit SinghReviewed by Susha Cheriyedath, M.Sc.May 6 2024

Quantum dot light-emitting diodes, or QLEDs, have emerged as a leading player in display technology. They offer a range of benefits, including richer colors, improved brightness, and energy efficiency. With its superior visual quality and performance, QLED is considered the next generation of visual displays after traditional LED.

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This article explores the field of QLEDs and examines its principles and applications in various sectors, highlighting advancements in display technology. It also discusses recent developments and challenges in the field.

From Pixels to Quantum Dots

The history of QLED technology can be traced back to the discovery and development of quantum dots (QDs). QDs are semiconductor nanoparticles with unique optical and electrical properties. Initially, QDs were studied for their fundamental properties in research laboratories. However, they soon caught the attention of display technology experts because of their ability to emit light of specific wavelengths when stimulated by an external light source. This property allowed QDs to be integrated into light-emitting devices, giving rise to QLED technology.¹

In the early stages of development, QLED technology faced challenges related to the synthesis and fabrication of QD materials. Scientists focused on improving the fabrication techniques to produce QDs that were uniform in quality, size, and composition. The goal was to produce QDs with narrow size ranges, ensuring consistent optical properties and color purity in display applications.^1,2

Over the years, significant progress has been made in the synthesis and manufacturing processes of QDs, leading to advancements in QLED technology. Researchers have developed techniques, including colloidal synthesis, chemical vapor deposition, and molecular beam epitaxy, to produce QDs with superior optical properties and stability. These advancements have paved the way for commercializing QLED displays in consumer electronics and other industries.^1,2

Fundamentals of QLEDs

QLED technology operates on the principle of electroluminescence, wherein light emission is induced by an electric current passing through a semiconductor material. In QLED displays, QDs serve as the emissive layer, where the recombination of electrons and holes results in the emission of photons. The critical components of a QLED display include QDs, an LED backlight, and color filters.¹

When the LED backlight emits light, it is absorbed by QDs, which then re-emit the light at specific wavelengths determined by their size. This process, called photoluminescence, allows QLED displays to produce a wide range of colors with high brightness and color accuracy. Manufacturers can control the size and composition of the QDs to tune the emitted light and achieve the desired color gamut, including primary colors such as red, green, and blue, as well as secondary and tertiary colors.¹

QLEDs Beyond the Living Room Walls

Integrating QDs in QLED displays provides several benefits over conventional LED-based displays. QDs exhibit a narrow emission spectrum, resulting in better colors and a wider color gamut and reproduction. Also, QDs have a high quantum yield, efficiently converting electrical energy into light, improving energy efficiency and brightness in QLED displays.^1,2

QDs used in QLED displays also have a longer lifespan than organic materials used in organic LED (OLED) displays, ensuring prolonged display performance. QLED displays are also immune to burn-in problems, a common issue in OLED displays.^1,2

Due to these advantages, QLED technology has many applications across various sectors. QLED displays have gained popularity in consumer electronics, especially televisions, computer monitors, and gaming consoles. These displays offer viewers an exceptional visual experience with their vibrant colors, high brightness, and sharp image quality.³

These displays are also widely used indoors and outdoors in digital signage applications. Their high brightness levels and color accuracy make them ideal for advertising, information displays, and interactive kiosks in retail stores, airports, stadiums, and other public spaces. QLED signage attracts attention and delivers messages effectively, even in brightly lit environments or direct sunlight.^2,3

Automotive manufacturers incorporate QLED displays into their infotainment systems, instrument clusters, and heads-up displays (HUDs). These displays offer a cost-effective solution with excellent visibility, readability, and durability. The ability to customize colors and brightness levels enhances the user experience and contributes to the overall aesthetics of the vehicle interior.⁴

In the medical industry, QLED displays are utilized in medical imaging applications, such as diagnostic monitors and surgical displays. Their high color accuracy and resolution enable healthcare professionals to visualize medical images with precision and detail, facilitating accurate diagnosis and treatment planning. QLED displays are also preferred for their long-term stability and reliability in critical healthcare environments.⁵

Gaming and entertainment applications also benefit from QLED technology thanks to its low input lag, high refresh rates, and immersive visual experience. Gaming monitors equipped with QLED displays offer gamers responsive gameplay with smooth motion and vibrant colors, enhancing the gaming experience. QLED technology also enables the reproduction of high dynamic range (HDR)  content, delivering enhanced contrast and realism in movies, streaming, and multimedia content.⁶

QLED displays are also used in industrial and professional applications, such as control rooms, surveillance systems, and design studios. Their reliability, longevity, and color accuracy make them suitable for mission-critical environments where continuous operation and accurate visual representation are essential. QLED displays enable professionals to monitor processes, analyze data, and collaborate effectively in various industries, including manufacturing, utilities, and architecture.

Challenges and Latest Developments

Despite its numerous advantages, QLED technology faces challenges that require addressing. One of the primary hurdles is enhancing the color accuracy and efficiency of QLED displays. The viewing angle of these displays is another issue that needs attention, as the viewing experience can be affected from extreme angles. Researchers are working tirelessly to overcome these challenges and enhance QLED technology.⁷

Recent advancements include the development of quantum dot enhancement films (QDEF), which enhance color performance by improving light extraction efficiency and color purity. Research into perovskite QDs has also shown promise in achieving even higher color purity and efficiency, potentially revolutionizing the future of QLED displays.^8-10

Another exciting development is the implementation of micro and mini-LED backlighting systems in QLED displays. These LEDs are smaller and more densely packed than traditional LEDs, allowing for finer control over local dimming zones and improved HDR performance. By combining micro and mini-LED backlighting with QD color filters, manufacturers can achieve higher contrast ratios, deeper blacks, and brighter highlights in QLED displays, rivaling the performance of OLED displays at a lower cost.¹¹

In addition to improvements in display performance, scientists have also explored novel applications of QLED technology in emerging fields such as augmented reality (AR) and virtual reality (VR). By integrating QLED displays into AR glasses and VR headsets, developers can deliver immersive visual experiences with realistic colors and sharp image quality, enhancing user engagement and immersion.¹²

The Future of QLED Technology

The future of QLED technology is promising. Continuous research and development efforts are underway to enhance color accuracy, efficiency, and scalability, making QLED displays the technology of choice across various industries.

As consumer demand for larger, thinner, and more energy-efficient displays continues to grow, QLED technology is expected to play a crucial role in meeting these demands. With advancements in manufacturing processes and materials, QLED displays will likely become more affordable and accessible to a broader range of consumers, further solidifying their position as the next evolution in display technology.

In conclusion, QLED is a significant milestone in display technology, as it can deliver vivid colors, high brightness, and energy efficiency. This revolutionary technology could transform industries like consumer electronics and automotive displays.

Despite the challenges, ongoing advancements and research initiatives continue to propel QLED technology forward, promising a future filled with more immersive and visually stunning displays. As the technology matures and becomes more accessible, QLED displays are poised to revolutionize visual content consumption, transforming the landscape of displays and visual experiences.

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References and Further Reading

1. Sun, Y., Jiang, Y., Sun, X. W., Zhang, S., Chen, S. (2019). Beyond OLED: Efficient Quantum Dot Light‐Emitting Diodes for Display and Lighting Application. The Chemical Record. doi.org/10.1002/tcr.201800191
2. Tian, D., Ma, H., Huang, G., Gao, M., Cai, F., Fang, Y., Li, C., Jiang, X., Wang, A., Wang, S., Du, Z. (2022). A Review on Quantum Dot Light‐Emitting Diodes: From Materials to Applications. Advanced Optical Materials. doi.org/10.1002/adom.202201965
3. Dai, X., Deng, Y., Peng, X., Jin, Y. (2017). Quantum-Dot Light-Emitting Diodes for Large-Area Displays: Towards the Dawn of Commercialization. Advanced Materials. doi.org/10.1002/adma.201607022
4. Zhou, C., Qiao, W., Hua, J., Chen, L. (2024). Automotive Augmented Reality Head-Up Displays. Micromachines. doi.org/10.3390/mi15040442
5. Cha, GD., Kim, DH. Kim, DC. (2024). Wearable and Implantable Light-Emitting Diodes and Their Biomedical Applications. Korean J. Chem. Eng. doi.org/10.1007/s11814-023-00006-z
6. Hotz, C., Yurek, J. (2021). Quantum Dot-Enabled Displays. Advanced Display Technology. Series in Display Science and Technology. Springer, Singapore. doi.org/10.1007/978-981-33-6582-7_10
7. Chen, Z., Li, H., Yuan, C., Gao, P., Su, Q., Chen, S. (2023). Color Revolution: Prospects and Challenges of Quantum‐Dot Light‐Emitting Diode Display Technologies. Small Methods. doi.org/10.1002/smtd.202300359
8. Ko, YH., Park, JG. (2018). Novel quantum dot enhancement film with a super-wide color gamut for LCD displays. Journal of the Korean Physical Society. doi.org/10.3938/jkps.72.45
9. Shan, Q., Dong, Y., Xiang, H., Yan, D., Hu, T., Yuan, B., Zhu, H., Wang, Y.,  Zeng, H. (2024). Perovskite Quantum Dots for the Next‐Generation Displays: Progress and Prospect. Advanced Functional Materials. doi.org/10.1002/adfm.202401284
10. Hu, H., Levchuk, I., Kalkowski, F., Elia, J., Osvet, A., Brabec, CJ. (2023). Engineering Stable Perovskite Quantum Dot Films for High Color Purity Display Applications. ACS Energy Letters. doi.org/10.1021/acsenergylett.3c01812
11. Miao, W., Hsiao, F., Sheng, Y., Lee, T., Hong, Y., Tsai, C., Chen, H., Liu, Z., Lin, C., Chung, R., Ye, Z., Horng, R., Chen, S., Kuo, H., He, J. (2023). Microdisplays: Mini‐LED, Micro‐OLED, and Micro‐LED. Advanced Optical Materials. doi.org/10.1002/adom.202300112
12. Park, SJ., Keum, C., Zhou, H., Lee, T., Choe, W., Cho, H. (2022). Progress and Prospects of Nanoscale Emitter Technology for AR/VR Displays. Advanced Materials Technologies. doi.org/10.1002/admt.202201070

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