New ways to synthesize lead sulfide nanosheets - substituted alkanes direct the growth of 2D nanostructures

TL;DR

This paper introduces new synthesis methods for lead sulfide nanosheets, demonstrating that alternative halogen alkanes and primary amines can be used, and that oleic acid alone can direct 2D growth at high temperature.

Contribution

It presents novel synthesis routes for PbS nanosheets using different ligands and shows oleic acid's sufficiency in directing anisotropic growth without coligands.

Findings

Use of various halogen alkanes and primary amines in synthesis.

Oleic acid alone can control 2D growth at 170°C.

Nanosheets with lateral dimensions over 10 microns achieved.

Abstract

Two-dimensional colloidal nanosheets represent very attractive optoelectronic materials. They combine good lateral conductivity with solution-processability and geometry-tunable electronic properties. In case of PbS nanosheets, so far the synthesis was driven by the addition of chloroalkanes as coligands. Here, we demonstrate how to synthesize two-dimensional lead sulfide nanostructures using other halogen alkanes and primary amines. Further, we show that at a reaction temperature of 170C a coligand is not even necessary, and the only ligand, oleic acid, controls the anisotropic growth of the two-dimensional structures and using thiourea as sulfide source, nanosheets with lateral dimensions of over 10 microns are possible.