Iodoplumbate Complex Transformation for Efficient Perovskite Emitters

Area of Science:

• Materials Science
• Optoelectronics
• Solid-State Chemistry

Background:

• High-quality perovskite emitters are essential for advanced optoelectronic devices.
• Additive engineering, particularly with amino-based molecules, has improved perovskite films but faces limitations in defect reduction.
• Existing methods struggle to lower trap density below ≈10^13 cm^-3, hindering photoluminescence quantum efficiency (PLQE).

Purpose of the Study:

• To investigate the mechanisms of defect formation in 3D perovskites during crystallization.
• To identify novel additives that can effectively suppress defects and enhance PLQE.
• To improve the performance of near-infrared perovskite light-emitting diodes (PeLEDs).

Main Methods:

• In situ monitoring of the perovskite crystallization process.
• Utilizing non-amino additives with ester and ether groups in perovskite precursor solutions.
• Characterization of trap density and photoluminescence quantum efficiency (PLQE) of the resulting perovskite films.

Main Results:

• Identified incomplete conversion of iodoplumbate complexes as a key source of defects in 3D perovskites.
• Demonstrated that non-amino additives promote complete precursor conversion before nucleation, effectively eliminating defect formation.
• Achieved a record low trap density of 4.8 × 10^12 cm^-3 and a peak PLQE of 84.5% in 3D perovskite films.
• Fabricated near-infrared PeLEDs with a high external quantum efficiency of 26.5%.

Conclusions:

• Non-amino additives containing ester and ether groups are highly effective in fabricating high-quality 3D perovskite films.
• Complete conversion of iodoplumbate complexes is critical for defect suppression and achieving high PLQE.
• This advancement paves the way for high-performance perovskite optoelectronics, particularly in the near-infrared spectrum.