Post-Synthesis Modification of Photoluminescent and Electrochemiluminescent Au Nanoclusters with Dopamine.

Jae Hyun Kim,Joohoon Kim

doi:10.3390/nano11010046

Abstract

Here, we report a post-synthesis functionalization of the shell of Au nanoclusters (NCs) synthesized using glutathione as a thiolate ligand. The as-synthesized Au NCs are subjected to the post-synthesis functionalization via amidic coupling of dopamine on the cluster shell to tailor photoluminescence (PL) and electrochemiluminescence (ECL) features of the Au NCs. Because the NCs’ PL at ca. 610 nm is primarily ascribed to the Au(I)-thiolate (SG) motifs on the cluster shell of the NCs, the post-synthesis functionalization of the cluster shell enhanced the PL intensity of the Au NCs via rigidification of the cluster shell. In contrast to the PL enhancement, the post-synthesis modification of the cluster shell does not enhance the near-infrared (NIR) ECL of the NCs because the NIR ECL at ca. 800 nm is ascribed to the Au(0)-SG motifs in the metallic core of the NCs.

Highlights

Au nanoclusters (Au NCs) comprising a small number of atoms, typically with a particle size of ~1 nm, have attracted intense research in both fundamental and applied disciplines as a promising class of functional nanomaterials [1,2,3]
In contrast to the PL enhancement, the post-synthesis modification of the cluster shell does not enhance the near-infrared (NIR) ECL of the NCs because the NIR ECL at ca. 800 nm is ascribed to the Au(0)-SG motifs in the metallic core of the NCs
This is because the ultra-small Au NCs exhibit unique molecular-like behaviors, such as photoluminescence (PL), molecular chirality, quantized double-layer charging, and electrochemiluminescence (ECL), distinctively different from their larger nanoparticle and bulk counterparts [9,10,11,12]

Summary

Introduction

Au nanoclusters (Au NCs) comprising a small number of atoms, typically with a particle size of ~1 nm, have attracted intense research in both fundamental and applied disciplines as a promising class of functional nanomaterials [1,2,3]. Au NCs have risen to the forefront of sensing, photovoltaic, and diagnostic research [4,5,6,7,8] This is because the ultra-small Au NCs exhibit unique molecular-like behaviors, such as photoluminescence (PL), molecular chirality, quantized double-layer charging, and electrochemiluminescence (ECL), distinctively different from their larger nanoparticle and bulk counterparts [9,10,11,12]. These distinctive properties were found to be highly dependent on the size, oxidation states, composition, and ligands of the Au NCs [13,14,15,16]. Among the various ligands studied so far, a hydrophilic tripeptide glutathione (GSH) has been useful for synthesizing

Methods

Results

Conclusion