Ultra-thin PbS sheets by two-dimensional oriented attachment

TL;DR

This paper demonstrates the synthesis of ultra-thin, single-crystal PbS sheets via two-dimensional oriented attachment, enabled by co-solvents and ligand packing, with potential applications in photodetectors.

Contribution

It introduces a novel method for creating 2D PbS nanosheets through oriented attachment, advancing nanocrystal assembly techniques.

Findings

Successful synthesis of ultra-thin PbS sheets with micrometer dimensions.

The process is initiated by co-solvents affecting nucleation and growth.

The nanosheets can be integrated into photodetectors without additional treatment.

Abstract

Controlling anisotropy is a key concept to generate complex functionality in advanced materials. For this, oriented attachment of nanocrystal building blocks, a self assembly of particles into larger single crystalline objects, is one of the most promising approaches in nanotechnology. We report here the 2D oriented attachment of PbS nanocrystals into ultra-thin single crystal sheets with dimensions on the micrometer scale. We found that this process is initiated by co-solvents which alter nucleation and growth rates during the primary nanocrystal formation and finally driven by dense packing of oleic acid ligands on {100} facets of PbS. The obtained nanosheets can be readily integrated in a photo-detector device without further treatment.