Stronger Lewis Base Antisolvents Improve Perovskite Nanocrystal Stability

Area of Science:

• Materials Science
• Nanotechnology
• Chemistry

Background:

• Lead-halide perovskite nanocrystals (NCs) are promising for optoelectronics.
• Antisolvent selection is critical for NC purification, affecting monodispersity, yield, and surface integrity.
• Current practices often use high-polarity antisolvents, contradicting theoretical recommendations.

Purpose of the Study:

• To investigate the role of antisolvent properties beyond polarity in perovskite NC purification.
• To establish a mechanistic understanding of antisolvent-surface interactions.
• To identify optimal antisolvents for enhanced stability and performance of halide perovskite NCs.

Main Methods:

• Data mining of antisolvent usage in perovskite NC purification.
• Comparative purification of CsPbI3 NCs using ethyl acetate and acetonitrile.
• Surface characterization using 1H NMR, FTIR, and XPS.
• Theoretical analysis via DFT calculations.

Main Results:

• Antisolvent polarity alone is insufficient for predicting purification outcomes.
• Acetonitrile, despite higher polarity, yielded superior colloidal stability compared to ethyl acetate.
• Acetonitrile acts as a stronger Lewis base, effectively passivating the perovskite NC surface.
• Enhanced surface passivation led to improved NC stability and performance in devices.

Conclusions:

• A mechanistic framework for antisolvent selection based on Lewis basicity and surface coordination is proposed.
• Acetonitrile is identified as a superior antisolvent for producing stable and high-performing halide perovskite NCs.
• This work provides a pathway for realizing brighter and more stable perovskite NC-based optoelectronic devices.