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Quantitative replacement of citrate by phosphane on silver nanoparticle surfaces monitored by Surface-Enhanced Raman Spectroscopy (SERS)

: Grass, Stefan; Diendorf, Jörg; Gebauer, Julia S.; Epple, Matthias; Treuel, Lennart


Journal of nanoscience and nanotechnology 15 (2015), No.2, pp.1591-1596
ISSN: 1533-4880
Deutsche Forschungsgemeinschaft DFG
SPP 1313;
Journal Article
Fraunhofer ICT-IMM ( IMM) ()
silver nanoparticles; surface enhanced Raman scattering; SERS; citrate; ligand exchange; colliod stability

Chemical approaches to metal NP synthesis commonly use capping agents to achieve a desired NP size and shape. Frequently, such NPs require chemically different surface ligands after synthesis to generate desired NP properties (e.g., charge or hydrophilicity) and to increase their long term colloidal stability. Here, we prepared SERS active citrate-stabilized silver NPs (d = 38±4 nm), purified them from remaining reactants by ultracentrifugation and redispersion, and immersed them into solutions containing different concentrations of Tris(sodium-m-sulfonatophenyl)phosphine (TPPTS), which is often used in such ligand replacement approaches to increase colloidal stability. After equilibration, SERS spectra were acquired, elucidating the concentration dependence of the ligand replacement reaction. SERS data were complemented by concentration dependent size measurements and relations between ligand exchange and colloidal stability are discussed.