Influence of Pt Alloying on the Fluorescence of Fully Inorganic, Colloidal Gold Nanoclusters

• Published in: Chemphyschem Vol. 23; no. 10; pp. e202200033 - n/a
• Main Authors: Ziefuss, Anna R., Willeke, Michael, Miertz, Matthias, Heinemann, Alexander, Rehbock, Christoph, Barcikowski, Stephan
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 18.05.2022; John Wiley and Sons Inc
• Subjects: analytical ultracentrifugation; Charge density; Chemical synthesis; colloidal alloy nanocluster; Fluorescence; Gold; laser based synthesis; Ligands; Nanoclusters; Noble metals; Photoluminescence; Platinum; Precious metal alloys; Surface charge; surface charge density; surfactant free photoluminescence; colloidal alloy nanocluster; analytical ultracentrifugation; surface charge density; surfactant free photoluminescence; laser based synthesis
• ISSN: 1439-4235; 1439-7641
• DOI: 10.1002/cphc.202200033

Noble metal alloy nanoclusters (NCs) are interesting systems as the properties of two or more elements can be combined in one particle, leading to interesting fluorescence phenomena. However, previous studies have been exclusively performed on ligand‐capped NCs from wet chemical synthesis. This makes it difficult to differentiate to which extent the fluorescence is affected by ligand‐induced effects or the elemental composition of the metal core. In this work, we used laser fragmentation in liquids (LFL) to fabricate colloidal gold‐rich bi‐metallic AuPt NCs in the absence of organic ligands and demonstrate the suitability of this technique to produce molar fraction series of 1nm alloy NC. We found that photoluminescence of ligand‐free NCs is not a phenomenon limited to Au. However, even minute amounts of Pt atoms in the AuPt NCs lead to quenching and red‐shift of the fluorescence, which may be attributed to the altered surface charge density. Laser‐generated, colloidal, and fully inorganic gold nanoclusters show a pronounced fluorescence. This study is a proof of concept on the former and reveals that the observed photoluminescence of these particles is not a phenomenon limited to Au. Herein, it is shown that colloidal, fully inorganic Pt and Au rich AuPt NCs are also fluorescent but behave differently in terms of emission energy and intensity.