Bright and efficient green ZnSeTe-based quantum-dot light-emitting diodes with EQE exceeding 20

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Ternary ZnSeTe quantum dots (QDs) are eco-friendly emitters for quantum-dot light-emitting diodes (QD-LEDs), with potential for blue, green, and red light emission.
• Despite advances in blue QD-LEDs, green and red ZnSeTe QDs suffer from poor performance due to a lack of effective defect passivation strategies.

Purpose of the Study:

• To enhance the luminescence performance and device efficiency of green ZnSeTe quantum dots.
• To overcome limitations in defect passivation for green and red emitting QDs.

Main Methods:

• Fabrication of gradient thick-shell quantum dots by inserting an ultrathin ZnSeS interlayer.
• Passivation of surface defects and alleviation of lattice mismatch at the shell-shell interface.

Main Results:

• Achieved enhanced quantum efficiency, improved optical stability, and elevated band position in ZnSeTe QDs.
• Demonstrated a record-breaking external quantum efficiency of 20.6% for green QD-LEDs.
• Reached a high brightness of 106,054 cd m⁻² with improved operational stability.

Conclusions:

• The ZnSeS interlayer strategy effectively passivates defects and improves the structural integrity of ZnSeTe QDs.
• This approach significantly boosts exciton recombination and charge injection balance, leading to high-performance QD-LEDs.
• The developed QD-LEDs show promising potential for efficient and stable optoelectronic applications.