Silver nanoparticle aggregate formation by a photochemical method and its application to SERS analysis

Photochemical reduction of silver(I) to silver nanoparticles was achieved, for the first time, in aqueous Triton X-100 medium using ascorbic acid. The particles show the usual plasmon absorption band of silver at 410 nm and a new band at 650 nm. Transmission electron microscope studies show that the size of the individual particles varies from 15 to 60 nm and the particles are in a string-like assembly. The particles are extremely stable and SERS active.