Diverse CsPbI₃ assembly structures: the role of surface acids

Area of Science:

• Materials Science
• Nanotechnology
• Solid-State Chemistry

Background:

• Anisotropic growth of halide perovskites is crucial for nanomaterial applications.
• Colloidal cesium lead iodide (CsPbI3) nanocrystals are less studied due to growth challenges.

Purpose of the Study:

• To investigate surface ligand engineering for controlling CsPbI3 nanocrystal morphology and properties.
• To achieve controlled self-assembly of CsPbI3 nanocrystals with enhanced optical performance.

Main Methods:

• Utilized varying molar ratios of surface acids and amines to control lead-iodine octahedra monomer concentration during nucleation.
• Employed in situ self-assembly of nanospheres and nanorods to form dumbbell-shaped CsPbI3 nanocrystals.
• Conducted structural and surface state analyses, including UV absorption.

Main Results:

• Successfully synthesized dumbbell-shaped CsPbI3 nanocrystals (average sizes 89 nm and 325 nm) with a high photoluminescence quantum yield of 89%.
• Demonstrated that benzenesulfonic acid promotes a Pb(SO3-)2-rich surface, increasing supersaturation and controlling monomer concentration.
• Observed distinct assembly morphologies and high photoluminescence quantum yields in CsPbI3-S nanocrystals, confirming the role of sulfonate groups.

Conclusions:

• Surface ligand engineering with benzenesulfonic acid effectively controls the self-assembly and morphology of CsPbI3 nanocrystals.
• The strategy offers a new pathway for rationally designing perovskite nanostructures with tailored properties.
• Achieved high photoluminescence quantum yields in CsPbI3 nanocrystals, paving the way for improved optoelectronic devices.