Issue 2, 2024

Unveiling the photoluminescence dynamics of gold nanoclusters with fluorescence correlation spectroscopy

Abstract

Gold nanoclusters (AuNCs) have captured significant interest for their photoluminescent properties; however, their rapid photodynamics remain elusive while probed by ensemble-averaging spectroscopy techniques. To address this challenge, we use fluorescence correlation spectroscopy (FCS) to uncover the photoluminescence dynamics of colloidal Au18(SG)14 nanoclusters. Our FCS analysis reveals the photoluminescence (PL) brightness per nanocluster, elucidating the impact of photoexcitation saturation and ligand interactions. Unlike DNA-encapsulated silver nanoclusters, their gold counterparts notably exhibit minimal blinking, with moderate amplitudes and 200 μs characteristic times. Our data also clearly reveal the occurrence of photon antibunching in the PL emission, showcasing the quantum nature of the PL process, with each AuNC acting as an individual quantum source. Using zero-mode waveguide nanoapertures, we achieve a 16-fold enhancement of the PL brightness of individual AuNCs. This constitutes an important enabling proof-of-concept for tailoring emission properties through nanophotonics. Overall, our study bridges the gap between ensemble-averaged techniques and single-molecule spectroscopy, offering new insights into AuNC photodynamics for biosensing and imaging applications.

Graphical abstract: Unveiling the photoluminescence dynamics of gold nanoclusters with fluorescence correlation spectroscopy

Supplementary files

Article information

Article type
Paper
Submitted
09 Okt. 2023
Accepted
02 Dec. 2023
First published
04 Dec. 2023
This article is Open Access
Creative Commons BY license

Nanoscale Adv., 2024,6, 570-577

Unveiling the photoluminescence dynamics of gold nanoclusters with fluorescence correlation spectroscopy

M. Kayyil Veedu, J. Osmólska, A. Hajda, J. Olesiak-Bańska and J. Wenger, Nanoscale Adv., 2024, 6, 570 DOI: 10.1039/D3NA00869J

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