Quantum-dot light-emitting diodes, better known as QLEDs, have been hailed as one of the most promising technologies for the next generation of displays.
With their brilliant colors and energy efficiency, QLEDs are already used in high-end TVs and monitors, but a longstanding problem has limited their full potential: short lifetimes caused by unstable materials.
Now, researchers in South Korea have developed a new material that dramatically improves both the efficiency and durability of QLEDs, setting a new performance record.
The study, led by Professor Youngu Lee and his team at the Department of Energy Science and Engineering at DGIST, was recently published in the journal Small.
Their innovation centers on the hole transport layer, or HTL, a thin film inside QLED devices that plays a key role in managing the flow of electric charge.
Traditionally, QLEDs use a triphenylamine-based HTL, but this material is vulnerable to electrical stress. Over time, its weak molecular bonds break down, leading to rapid drops in efficiency and shorter device lifetimes.
Attempts to solve this problem in the past often came with trade-offs. Strengthening the HTL sometimes reduced the movement of electrical charges, while improving charge mobility could weaken the device’s ability to block unwanted electron flow.
Professor Lee’s team tackled this challenge by creating a new HTL material based on a stable molecular structure called dibenzofuran.
This design increases the binding energy within the material, making it far more resistant to breakdown under stress.
At the same time, it improves hole mobility, reduces electron leakage, and minimizes surface defects—all essential features for building a high-performance QLED.
The results were groundbreaking. In green QLED devices, the new HTL material achieved an external quantum efficiency of 25.7%, an exceptionally high figure in this field. Even more impressive was the device’s lifetime.
At a brightness level of 100 candela per square meter, the QLED’s operating life (known as T₅₀) reached about 1.46 million hours.
That is 66 times longer than conventional devices using older HTL materials and represents the longest lifetime ever reported for this class of organic semiconductors.
“This breakthrough shows we can overcome the weaknesses of traditional HTL materials with weak molecular bonds,” said Professor Lee.
“By developing a stable, high-binding-energy HTL, we have dramatically boosted both the efficiency and longevity of QLEDs. Looking ahead, we plan to apply this approach not only to advanced display technologies but also to areas like solar cells.”
The development of this high-binding-energy HTL marks an important step toward making QLEDs more reliable for widespread use.
With the ability to maintain brightness and stability for far longer than before, these next-generation displays could soon become the standard in televisions, smartphones, and other devices that rely on vivid, energy-efficient screens.
