Elevating Charge Transport Layer for Stable Perovskite Light-Emitting Diodes

Area of Science:

• Materials Science
• Device Physics
• Solid-State Chemistry

Background:

• Ion migration in perovskite films is a key limitation for the long-term stability of perovskite light-emitting diodes (LEDs).
• Accumulation of excess halide ions at grain boundaries drives this ion migration, hindering commercial viability.
• Existing strategies often struggle to effectively suppress ion migration without compromising device performance.

Purpose of the Study:

• To develop a structural modification in perovskite LEDs to impede ion migration channels.
• To enhance the operational stability and commercial potential of perovskite LEDs.
• To investigate the mechanism by which the modified structure suppresses ion migration.

Main Methods:

• Engineered the hole transport layer (HTL) to reduce its wettability with the perovskite layer.
• Prevented HTL infiltration into perovskite grain boundaries, creating nanosized gaps.
• Utilized reduced perovskite wettability to form physical barriers against ion migration.

Main Results:

• Achieved significantly enhanced operational stability in perovskite LEDs, with half-lifetimes of 256 h at 100 mA cm⁻² and 1774 h at 20 mA cm⁻².
• Demonstrated that the engineered HTL effectively suppresses halide ion migration by creating nanosized gaps.
• Showcased the versatility of the approach by extending it to various perovskite LED architectures.

Conclusions:

• Elevating the hole transport layer between perovskite grain boundaries effectively impedes ion migration pathways.
• The developed method offers a promising strategy for realizing highly stable and commercially viable perovskite LEDs.
• This approach significantly surpasses the stability of organic LEDs at high brightness levels.