Very Stable and Efficient Tandem Quantum-Dot Light-Emitting Diodes Enabled by IZO-Based Interconnecting Layers.

Area of Science:

• Materials Science
• Optoelectronics
• Quantum Dot Technology

Background:

• Tandem quantum-dot light-emitting diodes (QLEDs) offer theoretical advantages in efficiency and stability for displays.
• Current tandem QLEDs suffer from practical limitations in operational stability compared to existing technologies.

Purpose of the Study:

• To engineer a novel tandem QLED structure for enhanced efficiency and stability.
• To address the limitations in driving voltage and light extraction in current devices.

Main Methods:

• Developed a barrier-free interconnecting layer using indium-zinc oxide and ZnMgO.
• Implemented a top-emitting structure and optimized cavity length via theoretical simulation.
• Fabricated and tested red tandem QLEDs.

Main Results:

• Achieved a remarkably reduced driving voltage due to the improved interconnecting layer.
• Maximized light extraction efficiency through structural and optical optimizations.
• Demonstrated a maximum external quantum efficiency of 49.01% for red tandem QLEDs.
• Attained a T₉₅ lifetime exceeding 50,000 hours at 1000 cd/m².

Conclusions:

• The new tandem QLED structure significantly enhances both efficiency and operational stability.
• This advancement positions the developed QLEDs among the most efficient and stable reported to date.
• The findings pave the way for next-generation display technologies with superior performance.