Efficient, Patternable Full-Color Perovskite Quantum Dot LEDs via Defect-Passivating Film-State Ligand Engineering

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Perovskite quantum dots (PeQDs) offer superior optoelectronic properties for advanced displays.
• Effective surface ligand modification is crucial for passivating defects and enhancing charge injection in PeQD-based light-emitting diodes (LEDs).
• Conventional film-state ligand exchange processes (C-FLEPs) often fail to fully passivate surface defects, limiting LED performance.

Purpose of the Study:

• To introduce an advanced film-state ligand exchange process (A-FLEP) for improved PeQD LED fabrication.
• To address surface defects more effectively using a multi-ligand passivation strategy.
• To enhance the electrical properties and performance of PeQD LEDs.

Main Methods:

• Developed an advanced film-state ligand exchange process (A-FLEP) incorporating a multi-ligand passivation strategy.
• Carefully modulated the polarity of the ligand solution to prevent unintended ligand detachment during A-FLEP.
• Fabricated and characterized PeQD LEDs using the A-FLEP method.

Main Results:

• Achieved high external quantum efficiency (EQE) and luminance in green (21.44%, 35,960 cd m⁻²), red (13.23%, 1,295 cd m⁻²), and blue (1.86%, 720 cd m⁻²) PeQD LEDs.
• Demonstrated significantly improved passivation of surface defects compared to conventional methods.
• Showcased enhanced electrical properties of PeQD LEDs through the A-FLEP.

Conclusions:

• The A-FLEP with multi-ligand passivation offers a superior method for fabricating high-performance PeQD LEDs.
• This strategy effectively overcomes limitations of C-FLEPs in defect passivation and charge injection.
• The developed A-FLEP holds significant promise for the advancement of next-generation display technologies.