High-Performance Green Light-Emitting Diodes Based on MAPbBr₃ with π-Conjugated Ligand

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Perovskite film morphology, crystal size, and trap density critically influence the luminescent properties of perovskite light-emitting diodes (PeLEDs).
• Ligand passivation of perovskite crystal surfaces is a key strategy to mitigate trap sites and enhance PeLED performance.

Purpose of the Study:

• To investigate the effect of 4-aminobenzonitrile (ABN) as a ligand on methylammonium lead bromide (MAPbBr3)-based PeLEDs.
• To improve PeLED performance through surface modification of the hole-transport layer (HTL).

Main Methods:

• Utilized 4-aminobenzonitrile (ABN) as a surface ligand for MAPbBr3 perovskite films.
• Reduced MAPbBr3 crystal size to the nanoscale and decreased trap density using ABN.
• Employed a surface-modified HTL with a hydrophilic polymer to further enhance PeLED properties.

Main Results:

• The ABN ligand successfully reduced MAPbBr3 crystal size and trap density.
• Surface modification of the HTL led to further improvements in PeLED characteristics.
• Fabricated a high-performance green PeLED achieving a maximum luminance of 3350 cd/m² and an external quantum efficiency of 8.85%.

Conclusions:

• The strategic use of ABN ligands is effective in optimizing perovskite film properties for PeLED applications.
• Optimizing both the perovskite layer with ligands and the charge-transport layer is crucial for developing high-performance PeLEDs.