Issue 17, 2024

Seeing is believing: what is on the surface of silver nanocrystals suspended in their original reaction solution

Abstract

Colloidal synthesis of inorganic nanocrystals always involves a multitude of ionic and molecular species. How the chemical species affect the evolution of nanocrystals remains a black box. As an essential ingredient in the polyol synthesis of Ag nanocubes, Cl has been proposed to co-adsorb on the surface with poly(vinyl pyrrolidone) (PVP) to facilitate shape evolution. However, there is still no direct evidence to confirm the presence of Cl on the surface of Ag nanocubes while they are suspended in the original reaction solution. By leveraging the high sensitivity of surface-enhanced Raman scattering, here we offer direct evidence, for the first time, by resolving the Ag–Cl vibrational peak at 240 cm−1. This characteristic peak disappears if the synthesis is conducted in the absence of Cl. Instead, three peaks associated with CF3COO (from the precursor to Ag) are observed. When the sample is diluted with ethylene glycol, all the peaks associated with CF3COO decrease proportionally in intensity, implying the involvement of chemisorption and negligible desorption during dilution. The chemisorbed CF3COO is readily replaced by Cl due to their major difference in binding strength. The co-adsorbed Cl forces the carbonyl group of PVP binding to the Ag surface to take a more perpendicular configuration, enhancing its peak intensity. Altogether, these findings shed new light on the roles played by various chemical species in a successful synthesis of Ag nanocubes.

Graphical abstract: Seeing is believing: what is on the surface of silver nanocrystals suspended in their original reaction solution

Supplementary files

Article information

Article type
Edge Article
Submitted
30 Jan 2024
Accepted
31 Mar 2024
First published
01 Apr 2024
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2024,15, 6321-6330

Seeing is believing: what is on the surface of silver nanocrystals suspended in their original reaction solution

Q. Huang, D. Qin and Y. Xia, Chem. Sci., 2024, 15, 6321 DOI: 10.1039/D4SC00730A

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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