Lanthanide‐Based Molecular Cluster‐Aggregates: Optical Barcoding and White‐Light Emission with Nanosized {Ln20} Compounds

• Published in: Angewandte Chemie International Edition Vol. 60; no. 11; pp. 6130 - 6136
• Main Authors: Gálico, Diogo A., Kitos, Alexandros A., Ovens, Jeffrey S., Sigoli, Fernando A., Murugesu, Muralee
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 08.03.2021
• Edition: International ed. in English
• Subjects: Aggregates; Bar codes; Clusters; Composition effects; Counterfeit; Counterfeiting; Emissions control; Energy transfer; Global economy; Labeling; lanthanides; Light emission; Metal-organic frameworks; molecular cluster-aggregates; Nanoparticles; optical barcodes; Optical properties; Security; white-light emission; energy transfer; molecular cluster-aggregates; optical barcodes; lanthanides; white-light emission
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202013867

Counterfeit goods represent a major problem to companies, governments, and customers, affecting the global economy. In order to protect the authenticity of products and documents, optical anti‐counterfeit technologies have widely been employed via the use of discrete molecular species, extended metal–organic frameworks (MOFs), and nanoparticles. Herein, for the first time we demonstrate the potential use of molecular cluster‐aggregates (MCA) as optical barcodes via composition and energy transfer control. The tuneable optical properties for the [Ln20(chp)30(CO3)12(NO3)6(H2O)6], where chp−=deprotonated 6‐chloro‐2‐pyridinol, allow the fine control of the emission colour output, resulting in high‐security level optical labelling with a precise read‐out. Moreover, a unique tri‐doped composition of GdIII, TbIII, and EuIII led to MCAs with white‐light emission. The presented methodology is a unique approach to probe the effect of composition control on the luminescent properties of nanosized molecular material. The control of the energy transfer and the emission colour is demonstrated for the first time in molecular cluster‐aggregates. Moreover, through the targeted choice of the lanthanide composition, a novel pure white‐light emitting cluster‐aggregate was isolated. This approach can pave new avenues into the future of efficient optical anti‐counterfeiting technologies.