On July 15, the Hong Kong University of Science and Technology officially announced the development of a new generation of QRLED, which will revolutionize smartphones and televisions with ultra-high brightness and rich colors.
Researchers at the Faculty of Engineering at the Hong Kong University of Science and Technology have overcome a major challenge in display technology by developing the world's brightest and most energy-efficient quantum rod LED (QRLED).
These next-generation QRLEDs achieve optimized deep green emission at the top of the color triangle, giving displays unprecedented color purity and a maximized color gamut. These cutting-edge light sources offer longer lifespans and are three times brighter than previous models, providing energy-efficient, ultra-vibrant visuals for smartphones, TVs, and AR/VR devices, while further enhancing color performance.
Image source: Hong Kong University of Science and Technology
A press release from the Hong Kong University of Science and Technology states that light-emitting diodes (LEDs) have been widely used in electronic products for decades. Recent advances in quantum materials have given rise to quantum dot LEDs (QLEDs) and QRLEDs. Both offer narrow emission bandwidth and high color purity, surpassing traditional LEDs. Among these technologies, QRLEDs stand out due to their higher light output coupling efficiency. However, QRLEDs face challenges: their green emission performance is not as good as QLEDs due to low charge injection efficiency, interfacial electron leakage, and structural barriers that hinder charge transport and stability (such as thick insulating shells and long organic ligands (molecules attached to the surface of nanorods)).
To address these issues, a team led by Associate Professor Abhishek K. SRIVASTAVA of the Department of Electronic and Computer Engineering at the Hong Kong University of Science and Technology has innovatively designed a novel green luminescent quantum rod with a customized core gradient alloy structure and a minimized shell thickness.
This design achieves high-brightness deep green emission (515-525 nm) at the color triangle peak, thereby maximizing the display's color gamut. The team also designed a uniformly smooth, shorter quantum rod, enabling tight, gapless film stacking. Further innovations include shorter organic ligands and a bilayer hole transport layer, which together enhance charge balance and suppress electron leakage, thereby improving efficiency and stability.
This invention achieves high performance in the following areas:
- Recording efficiency: Converts electrical energy into light more efficiently than ever before, with an external quantum efficiency (EQE) of 24%, compared to 22% for the older model.
- Luminous output per unit of energy: 89 cd A1 (candela per ampere), a metric for luminous output per unit of energy, exceeding all existing QRLEDs.
- Ultra-bright output: 3 times brighter than the old green LED, reaching a peak brightness of over 500,000 cd m2.
- Leap in lifespan: Demonstrating over 22,000 hours of operational stability, making the technology suitable for commercial display applications.
(Source: IT Home)
