Interface-Mediation-Enabled High-Performance Near-Infrared AgAuSe Quantum Dot Light-Emitting Diodes.

Area of Science:

• Optoelectronics
• Materials Science
• Nanotechnology

Background:

• Near-infrared quantum dot light-emitting diodes (NIR-QLEDs) are crucial for night-vision and tracking.
• Existing high-performance NIR-QLEDs often rely on lead (Pb)-containing materials, posing environmental concerns.
• Environmentally benign alternatives have historically underperformed compared to Pb-based devices.

Purpose of the Study:

• To develop high-performance, environmentally benign NIR-QLEDs.
• To investigate interface engineering strategies for improving QD device performance.
• To overcome the performance gap between benign and Pb-containing NIR-QLEDs.

Main Methods:

• Fabrication of NIR-QLEDs using silver-gold-selenide (AgAuSe) quantum dots (QDs).
• Implementation of cysteamine-treated QD film contact heterointerfaces for defect elimination.
• Utilizing coordinated additives to optimize charge injection balance via dipole moment manipulation.

Main Results:

• Achieved record external quantum efficiency (EQE) of 15.8% and power conversion efficiency (PCE) of 12.7% at 1046 nm.
• Demonstrated a low sub-band gap turn-on voltage of 0.9 V.
• Observed sustained high EQE over a wide current density range (0.0017 to 0.31 mA cm⁻²).

Conclusions:

• Cysteamine treatment effectively mitigates contact defects in AgAuSe QD films.
• Interface engineering with specific additive orientations optimizes charge injection for superior device performance.
• This work presents a viable strategy for practical, high-performance, environmentally benign NIR-QLED applications.