Issue 21, 2023

Delayed luminescence guided enhanced circularly polarized emission in atomically precise copper nanoclusters

Abstract

Metal nanoclusters, owing to their intriguing optical properties, have captivated research interest over the years. Of special interest have been chiral nanoclusters that display optical activity in the visible region of the electromagnetic spectrum. While the ground state chiral properties of metal nanoclusters have been reasonably well studied, of late research focus has shifted attention to their excited state chiral investigations. Herein, we report the synthesis and chiral investigations of a pair of enantiomerically pure copper nanoclusters that exhibit intense optical activity, both in their ground and excited states. The synthesis of nanoclusters using L- and D-isomers of the chiral ligand led to the formation of metal clusters that displayed mirror image circular dichroism and circularly polarized luminescence signals. Structural validation using single crystal XRD, powder XRD and XPS in conjunction with chiroptical and computational analysis helped to develop a structure–property correlation that is unique to such clusters. Investigations on the mechanism of photoluminescence revealed that the system exhibits long excited state lifetimes. A combination of delayed luminescence and chirality resulted in circularly polarized delayed luminescence, a phenomenon that is rather uncommon to the field of metal clusters. The chiral emissive properties could be successfully demonstrated in free-standing polymeric films highlighting their potential for use in the field of data encryption, security tags and polarized light emitting devices. Moreover, the fundamental understanding of the mechanism of excited state chirality in copper clusters opens avenues for the exploration of similar effects in a variety of other clusters.

Graphical abstract: Delayed luminescence guided enhanced circularly polarized emission in atomically precise copper nanoclusters

Supplementary files

Article information

Article type
Edge Article
Submitted
07 Feb 2023
Accepted
24 Apr 2023
First published
25 Apr 2023
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., 2023,14, 5593-5601

Delayed luminescence guided enhanced circularly polarized emission in atomically precise copper nanoclusters

C. Dutta, S. Maniappan and J. Kumar, Chem. Sci., 2023, 14, 5593 DOI: 10.1039/D3SC00686G

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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