High-Performance Perovskite Light-Emitting Diode with Enhanced Operational Stability Using Lithium Halide Passivation

Area of Science:

• Materials Science
• Optoelectronics
• Solid-State Chemistry

Background:

• Defect passivation is crucial for improving radiative recombination in perovskites, enhancing device performance in perovskite light-emitting diodes (LEDs).
• Current passivation agents, often organic chelating molecules, compromise charge transport and thermal stability, limiting operational device stability.
• Halide vacancies in perovskites create defects that hinder device performance and stability.

Purpose of the Study:

• To investigate lithium halides as novel defect passivation agents for perovskite films.
• To improve the efficiency and operational stability of perovskite light-emitting diodes (LEDs).
• To demonstrate the universal applicability of lithium halide passivation across different colors of perovskite LEDs.

Main Methods:

• Utilized lithium halides to passivate defects caused by halide vacancies in perovskite films.
• Reduced trap state density and suppressed ion migration in perovskite films.
• Fabricated and characterized green, blue, and red perovskite LEDs using lithium halide passivation.

Main Results:

• Achieved efficient green perovskite LEDs based on CsPbBr₃ with a peak external quantum efficiency of 16.2% and high maximum brightness (50,270 cd/m^-2).
• Demonstrated decent device stability under high brightness conditions (10⁴ cd/m^-2).
• Showcased improved efficiency in blue and red perovskite LEDs, highlighting the universal applicability of lithium halide passivation.

Conclusions:

• Lithium halides are effective defect passivating agents for perovskites, reducing trap states and ion migration.
• This passivation strategy significantly enhances the performance and stability of perovskite LEDs.
• Lithium halide passivation offers a versatile approach to improving various colors of perovskite light-emitting devices.