A facile synthesis of highly stable and luminescent Ag clusters: a steady-state and time-resolved spectroscopy study

Abstract

In this paper, we reported a very simple and environmentally friendly procedure for the synthesis of bright luminescent and nearly monodisperse Ag nanoclusters stabilized by a poly(N-vinylpyrrolidone) homopolymer.In this synthesis route acetonitrile or N,N-dimethylformamide (DMF) acts as both solvent and a reducing agent at their respective reflux temperatures. The as-prepared Ag clusters were found to be highly stable in various solvents as well as show nearly no changes in their emission intensity in solutions with different pH values and ionic strengths. Remarkably, the acetonitrile method predominantly produces blue emitting Ag clusters with a photoluminescence (PL) emission maximum at 424 nm (quantum yield 3.5%), whereas mainly blue-green emitting Ag clusters with the PL emission maximum at 450 nm (quantum yield 2.7%) were formed using the DMF method. The photo-physical, electronic, structural and morphological properties of the Ag clusters were investigated by performing UV/Vis absorption spectroscopy, stationary and time-resolved PL spectroscopy, X-ray photoelectron spectroscopy, femtosecond transient absorption spectroscopy, and transmission electron microscopy experiments.

Polyvinyl-Pyrrolidone-Coated Silver Nanoparticles—The Colloidal, Chemical, and Biological Consequences of Steric Stabilization under Biorelevant Conditions

“…However, the presence of FBS induced a rather unique effect on the SPR of AgNPs, revealing interesting details of the mechanisms associated with nanosilver degradation due to NaCl. According to the literature, the observed changes of SPR characteristics in the UV-Vis spectra can be attributed to the formation of clusters consisting of silver or silver chloride [41,42]. These clusters were most likely formed in the previous experiments as well but were immediately converted to bulk AgCl precipitation.…”

A facile one-pot synthesis of blue and red luminescent thiol stabilized gold nanoclusters: a thorough optical and microscopy study

“…biological imaging, labelling and therapeutics). Several reports are available where gold nanoclusters were prepared using proteins, 19 dendrimers, 20 amino acids, 21 DNA 22 and polyelectrolytes 23 as scaffolds. However, most of the methods mentioned above need an expensive starting material, photoirradiation, electric field application or an external toxic reducing agent such as sodium borohydride.…”

Fine-Tuning Synthesis of Fluorescent Silver Thiolate Nanoclusters

“…The more pronounced shift for NC3 system can be related to a stronger interaction between Ag and the thiolate ligands, due to the higher SR:Ag ratio used in the synthetic procedure. Moreover, very similar absorption features in the UV and visible region of the spectrum for Ag thiolate NCs synthesized using different thiolate ligands have already been observed [35,36].…”