Effect of atmospheric exposure on the growth of citrate-capped silver nanoparticles

✍ Scribed by Manish Kumar; G.B. Reddy

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 910 KB
• Volume: 42
• Category: Article
• ISSN: 1386-9477
• DOI: 10.1016/j.physe.2010.03.002

✦ Synopsis

Citrate-capped Ag nanoparticles are prepared at 8 o C in aqueous solution by a modified 'Turkevich' approach using NaBH 4 as reducing agent. Spherical Ag nanoparticles are observed in fresh solution having average size 10-15 nm with a narrow size distribution. UV-vis-NIR spectroscopic result shows a 'surface plasmon resonance' induced absorption peak at 389 nm in fresh solution. When the nanoparticles are exposed to atmosphere for 7 days, an enhancement in average size from 10 to 22 nm is observed and corresponding absorption peak is shifted from 389 to 425 nm. When exposure time is increased for a very long duration (17 months), chain formation in Ag nanoparticles is observed. The elemental state of Ag nanoparticles is confirmed with X-ray photoelectron spectroscopic study. The formation and growth mechanism of Ag nanoparticles is explained.