Seed-Mediated Synthesis of Thin Gold Nanoplates with Tunable Edge Lengths and Optical Properties

Abstract

Thin Au nanoplates show intriguing localized surface plasmon resonance (LSPR) properties with potential applications in various fields. The conventional synthesis of Au nanoplates usually involves the formation of spherical nanoparticles or produces nanoplates with large thicknesses. Herein, we demonstrate a synthesis of uniform thin Au nanoplates by using Au–Ag alloy nanoframes obtained by the galvanic replacement of Ag nanoplates with HAuCl4 as the seeds and a sulfite (SO32−) as a ligand. The SO32− ligand not only complexes with the Au salt for the controlled reduction kinetics but also strongly adsorbs on Au {111} facets for effectively constraining the crystal growth on both basal sides of the Au nanoplates for controlled shape and reduced thicknesses. This seed-mediated synthesis affords Au nanoplates with a thickness of only 7.5 nm, although the thickness increases with the edge length. The edge length can be customizable in a range of 48–167 nm, leading to tunable LSPR bands in the range of 600–1000 nm. These thin Au nanoplates are applicable not only to surface-enhanced Raman spectroscopy with enhanced sensitivity and reliability but also to a broader range of LSPR-based applications.

Advances in CO2 utilization employing anisotropic nanomaterials as catalysts: a review

“…By fine-tuning the shape of the gold nanoparticles, the authors were able to enhance the light-harvesting capabilities of the hybrid nanoparticles. Qiao et al came up with a stable seed-mediated synthesis method for making Au nanoplates with less thickness, a high morphological yield, and optical properties that can be controlled ( Qiao et al, 2023 ). Here, authors illustrate how to make uniformly thin Au nanoplates by utilizing Au-Ag alloy nanoframes produced by galvanic replacement of Ag nanoplates with HAuCl 4 and a sulfite (SO 3 2- ) as seeds and ligands, respectively.…”