Enhanced luminescence of Ag nanoclusters via surface modification.
In this work we present a detailed study on the influence of surface modifications for luminescent silver (Ag) clusters. Ag clusters (25 atoms) capped with dihydrolipoic acid show a distinct absorbance spectrum with several sharp transitions, and relative broad deep red luminescence with a quantum yield of 5% combined with a remarkably long luminescence lifetime of ~3 μs at room temperature. Both pH and the presence of coordinating ligands influence the absorbance spectra and fluorescence intensity. A strong increase in luminescence intensity up to 45% quantum yield could be induced by coordination with PEG ligands.


CONCLUSIONS
the surface coordination of the Ag clusters strongly influences the optical properties.
Leiden University Medical Center, Interventional Molecular Imaging Laboratory, Department of Radiology, Leiden, The Netherlands. p.t.k.chin@lumc.nl
Patrick T K
PT
Chin
Marte
M
van der Linden
Elleke J
EJ
van Harten
Arjan
A
Barendregt
Marcus T M
MT
Rood
Abraham J
AJ
Koster
Fijs W B
FW
van Leeuwen
Celso
C
de Mello Donega
Albert J R
AJ
Heck
Andries
A
Meijerink