Synthesis and characterization of silver colloidal nanoparticles with different coatings for SERS application

• Published in: Journal of nanoparticle research : an interdisciplinary forum for nanoscale science and technology 2014-12, Vol.16 (12), p.1-13, Article 2748
• Main Authors: Mikac, L., Ivanda, M., Gotić, M., Mihelj, T., Horvat, L.
• Format: Article
• Language: English
• Subjects: Borohydrides; Characterization and Evaluation of Materials; Chemical reduction; Chemistry and Materials Science; Citrates; Colloids; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Inorganic Chemistry; Lasers; Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties; Materials Science; Nanocrystalline materials; Nanoparticles; Nanoscale materials and structures: fabrication and characterization; Nanotechnology; Optical Devices; Optics; Photonics; Physical Chemistry; Physics; Raman scattering; Reagents; Research Paper; Silver; Sodium; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Zeta potential
• ISSN: 1388-0764; 1572-896X
• DOI: 10.1007/s11051-014-2748-9

Silver colloids were produced by chemical reduction of silver salt (silver nitrate, AgNO 3 ) solution. As reducing agents, trisodium citrate, sodium borohydride, ascorbic acid, polyvinylpyrrolidone, and glucose were used. The colloids were characterized by UV–Vis, DLS, zeta potential measurements, and SEM. The colloids were stabilized with negative groups or large molecules attached to their surface. The surface-enhanced Raman scattering (SERS) effect of stabilized nanoparticles was measured by using pyridine and rhodamine 6G molecules as analytes and NaNO 3 , KCl, and KBr at different concentrations as aggregating agents. The best Raman signal enhancement was achieved using silver nanoparticles of 40 nm size reduced and stabilized with citrate. The SERS signal of analyte molecules was further enhanced with the addition of sodium borohydride as an alternative aggregating agent. The borohydride had the strongest impact on the SERS effect of the colloid consistent of large (0.5 µm) silver nanoparticles stabilized with aminodextran. The mixture colloid-borohydride-pyridine was stable for hours. The mechanism of borohydride in the colloids is discussed.