One-pot silver nanoring synthesis

Abstract

Silver colloidal nanorings have been synthesized by reducing silver ions with NaBH 4 in trisodium citrate buffers. pH increase, by addition of NaOH, was used to speed up reduction reaction. The UV-vis absorption spectra of resulting silver nanorings showed two peaks accounting for transverse and longitudinal surface plasmon resonance, at ≈400 nm, and between 600 and 700 nm, respectively. The shapes of these silver nanoparticles (nanorings) depended on AgNO 3/NaBH 4 ratio, pH and reaction temperature. Particles were analysed by transmission electron microscopy, scanning electron microscopy and X-ray diffraction. A reaction pathway is proposed to explain silver nanoring formation. © The Author(s) 2009.