Perovskite Light-Emitting Diodes with an External Quantum Efficiency Exceeding 30

Area of Science:

• Optoelectronics
• Materials Science

Background:

• Perovskite light-emitting diodes (PeLEDs) offer high color purity and low-cost fabrication for displays and lighting.
• Current PeLEDs lag behind organic light-emitting diodes (OLEDs) in efficiency due to unoptimized charge transport and light outcoupling.

Purpose of the Study:

• To develop ultrahigh-efficiency green PeLEDs by optimizing charge carrier transport and light outcoupling.
• To address electron leakage and photon loss in PeLEDs for improved performance.

Main Methods:

• Utilized Ni_0.9 Mg_0.1 O_x films as a hole injection layer for enhanced hole mobility and balanced charge injection.
• Incorporated a polyethylene glycol layer to block electron leakage and minimize photon loss.
• Engineered near-field light distribution for efficient light outcoupling.

Main Results:

• Achieved external quantum efficiencies (EQE) surpassing 30%, with a record 30.84% EQE.
• Reached a high light outcoupling efficiency of 41.82%.
• Demonstrated stable performance with an average EQE of 29.05 ± 0.77% at 6514 cd m^-2.

Conclusions:

• Optimized charge carrier transport and light outcoupling are crucial for high-efficiency PeLEDs.
• The developed PeLED structure significantly reduces electron leakage and photon loss.
• This work presents a viable strategy for constructing super high-efficiency PeLEDs.