Copper sulfide nanosheets with shape-tunable plasmonic properties in the NIR

TL;DR

This study demonstrates precise shape and size control of copper sulfide nanosheets with tunable plasmonic properties in the near-infrared, using simple precursor tuning and theoretical modeling to understand their formation and spectral features.

Contribution

It introduces a straightforward method to synthesize shape-controlled copper sulfide nanosheets and provides a detailed analysis of their plasmonic properties through experiments and simulations.

Findings

Shape and size of CuS nanosheets can be precisely tuned.

Spectral features depend on particle shape and size.

Mechanism for shape formation is proposed based on experimental and theoretical data.

Abstract

2D copper sulfide nanocrystals are promising building blocks for plasmonic materials in the near-infrared (NIR) spectral region. We demonstrate precise shape and size control (hexagonal/triangle) of colloidal plasmonic copper sulfide (covellite) nano-prisms simply by tuning the precursors concentration without introduction of additional ligands. The ultra-thin 2D nanocrystals possess sizes between 13 and 100 nm and triangular or hexangular shapes. We also demonstrate CuS nanosheets (NSs) with lateral sizes up to 2 microns using a syringe pump. Based on the experimental findings and DFT simulations we propose a qualitative and quantitative mechanism for the formation of different shapes. The analysis of the spectral features in the NIR of synthesized CuS nanocrystals has been performed in respect to the shape and the size of particles by the discrete dipole approximation method and the Drude-Sommerfeld theory.