Highly Efficient Halide Perovskite Light-Emitting Diodes via Molecular Passivation

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Metal halide perovskites show promise for light-emitting diodes (LEDs).
• Defects-mediated nonradiative losses limit the efficiency of perovskite-based LEDs (PeLEDs).

Purpose of the Study:

• To develop molecular passivators for defect passivation in metal halide perovskites.
• To enhance the performance of perovskite-based LEDs (PeLEDs).

Main Methods:

• Synthesis of molecular passivators with varying anchoring groups.
• Passivation of perovskite thin films.
• Characterization of optoelectronic properties, grain size, and surface roughness.
• Fabrication and testing of perovskite-based LEDs (PeLEDs).

Main Results:

• Passivated perovskite thin films showed improved optoelectronic properties, reduced grain size, and lower surface roughness.
• An imidazolium-terminated passivator enabled highly efficient PeLEDs with a 15.6% external quantum efficiency.
• In situ formation of low-dimensional perovskite phases on nanograins was identified as the mechanism for surface defect passivation.

Conclusions:

• Molecular passivators effectively reduce defects and enhance the performance of PeLEDs.
• The strategy of forming low-dimensional perovskite phases is key to surface defect passivation.
• This work provides fundamental insights into using organic molecular passivators to boost PeLED efficiency.