Comprehensive Passivation for High-Performance Quasi-2D Perovskite LEDs

Area of Science:

• Materials Science
• Optoelectronics
• Chemistry

Background:

• Quasi-2D perovskites show promise for high-performance light-emitting diodes (LEDs).
• Effective defect passivation is crucial for enhancing perovskite LED efficiency.
• Current passivation methods struggle to address defects across surfaces, bulk, and interfaces in perovskite films.

Purpose of the Study:

• To develop novel passivating agents for comprehensive defect management in quasi-2D perovskite films.
• To improve the efficiency, stability, and operational characteristics of quasi-2D perovskite LEDs.
• To provide design guidelines for passivators in perovskite optoelectronics.

Main Methods:

• Synthesis of 9,9-substituted fluorene derivatives with tailored functional groups.
• Application of these derivatives for surface, bulk, and interfacial defect passivation in quasi-2D perovskite films.
• Fabrication and characterization of quasi-2D perovskite LEDs incorporating the passivated films.

Main Results:

• Fluorene derivatives effectively reduced nonradiative recombination, suppressed ion migration, and filled interfacial traps.
• External quantum efficiency of quasi-2D perovskite LEDs increased from 18.2% to 23.2%.
• Device operational lifetime improved by over six times, with a simultaneous reduction in turn-on voltage.

Conclusions:

• Comprehensive passivation using tailored fluorene derivatives significantly enhances quasi-2D perovskite LED performance.
• Addressing defects at all levels—surface, bulk, and interface—is critical for device optimization.
• The developed passivators and design principles offer a pathway for advancing perovskite optoelectronics.