Morphological transformations and fusion of PbSe nanocrystals studied using atomistic simulations

Area of Science:

• Materials Science
• Nanotechnology
• Computational Chemistry

Background:

• Lead selenide (PbSe) nanocrystals are crucial in various applications.
• Understanding nanocrystal assembly is key to controlling material properties.
• Classical interaction potentials for PbSe nanocrystals require development.

Purpose of the Study:

• To investigate the fusion mechanisms of capped and uncapped PbSe nanocrystals.
• To elucidate the role of interparticle dipole interactions in nanocrystal attachment.
• To determine the surface termination of capped PbSe facets.

Main Methods:

• Molecular dynamics simulations were conducted.
• Newly developed classical interaction potentials were employed.
• Simulations focused on capped and uncapped PbSe nanocrystals.

Main Results:

• Uncapped PbSe nanocrystals fuse efficiently via direct surface attachment, irrespective of initial alignment.
• Interparticle dipole interactions were found to be insignificant in the oriented attachment of uncapped nanocrystals.
• Presumably polar, capped PbSe{111} facets were shown to be neither fully Pb- nor Se-terminated.

Conclusions:

• Direct surface attachment is the primary mechanism for uncapped PbSe nanocrystal fusion.
• The role of dipole-dipole interactions in oriented attachment is less significant than previously thought.
• Surface capping influences the termination of PbSe facets, preventing complete Pb or Se termination.