High-performance large-area quasi-2D perovskite light-emitting diodes

Area of Science:

• Materials Science
• Optoelectronics
• Chemical Engineering

Background:

• Perovskite light-emitting diodes (PeLEDs) show promise but suffer performance degradation with increasing active area.
• This decline is primarily attributed to phase-segregation in the active film during fabrication.
• Existing fabrication methods struggle to produce uniform, large-area films without defects.

Purpose of the Study:

• To investigate the failure mechanism of large-area PeLED fabrication.
• To develop a method for suppressing phase-segregation in perovskite films.
• To achieve high-efficiency, large-area quasi-2D PeLEDs.

Main Methods:

• Investigated the phase-segregation mechanism in standard perovskite film fabrication.
• Introduced L-Norvaline to form a COO-coordinated intermediate phase.
• Modified crystallization pathways to suppress phase-segregation and improve film quality.
• Optimized recombination kinetics for enhanced device performance.

Main Results:

• Identified severe phase-segregation as the key failure mechanism for large-area PeLEDs.
• L-Norvaline successfully created a low-enthalpy intermediate phase, altering crystallization and suppressing segregation.
• Produced high-quality, large-area quasi-2D perovskite films.
• Demonstrated highly efficient green quasi-2D PeLEDs with active areas up to 9.0 cm².
• Achieved a peak external quantum efficiency (EQE) of 16.4% for n=3 and high luminance (9.1 × 10⁴ cd/m²) for n=10.

Conclusions:

• L-Norvaline is an effective additive for fabricating high-quality, large-area perovskite films by controlling phase-segregation.
• The developed method enables the production of efficient and bright large-area quasi-2D PeLEDs.
• This work represents a significant advancement in scalable perovskite optoelectronics.