Nanoplatelet modulation in 2D/3D perovskite targeting efficient light-emitting diodes

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Two-dimensional (2D) perovskite nanoplatelets offer high electroluminescence (EL) efficiency due to quantum confinement.
• However, 2D structures (〈n〉 = 1) can suffer from thermal quenching, reducing luminescence at room temperature.

Purpose of the Study:

• To develop a strategy for suppressing the formation of detrimental 2D NMA₂PbBr₄ nanoplatelets.
• To enhance the photoluminescence quantum yield (PLQY) and electroluminescence (EL) efficiency of perovskite-based LEDs.

Main Methods:

• Tuning the precursor ratios of cesium bromide (CsBr), formamidinium bromide (FABr), and 1-naphthylmethylammonium bromide (NMABr).
• Investigating the effect of long-chain ligand (NMABr) concentration on perovskite crystal size and PLQY.
• Utilizing FABr incorporation to further control the growth of NMA₂PbBr₄ in 2D/3D perovskite films.

Main Results:

• Increasing NMABr ratio below 60% decreased sub-domain size, enhancing PLQY via size confinement.
• Higher NMABr ratios increased NMA₂PbBr₄ content, negatively impacting EL efficiency.
• FABr incorporation effectively suppressed NMA₂PbBr₄ growth, yielding a compact film with ~61% PLQY.
• The optimized green perovskite LED achieved a current efficiency of 46.8 cd A⁻¹ and external quantum efficiency of 14.9%.

Conclusions:

• A simple precursor tuning strategy effectively modulates perovskite crystal structure for improved LED performance.
• Reduced NMA₂PbBr₄ content and controlled crystal size are key for high-efficiency perovskite LEDs.
• This method offers a pathway for developing high-performance perovskite-based optoelectronic devices.