A Demulsification-Crystallization Model for High-Quality Perovskite Nanocrystals.

Area of Science:

• Materials Science
• Nanotechnology
• Chemistry

Background:

• Room-temperature synthesis of metal halide perovskite nanocrystals (PNCs) using nonpolar solvents is attractive due to reduced sensitivity to polar solvents.
• Understanding the underlying mechanisms of precursor state and crystallization in PNC synthesis is crucial for technique advancement.

Purpose of the Study:

• To elucidate the mechanism of PNC formation in nonpolar solvents.
• To improve the efficiency of PNC-based light-emitting diodes (LEDs).

Main Methods:

• Systematic study of lead (Pb) precursors.
• In situ characterization of PNCs.
• Development of a demulsification-crystallization (D-C) model.
• Application of a multiple-acid-anion synergistic strategy.

Main Results:

• The Pb precursor exhibits reverse micelle behavior, leading to a novel D-C model involving two-stage nucleation separated by demulsification.
• High-quality PNCs were synthesized by tailoring the D-C model.
• A record external quantum efficiency of 22.5% was achieved for green LEDs based on these PNCs.

Conclusions:

• The D-C model provides fundamental insights into PNC formation in nonpolar solvents.
• The developed strategy enables the synthesis of high-performance PNCs for optoelectronic applications.
• This work opens new avenues for diverse PNC synthesis approaches.