Reproducible synthesis of silver colloidal particles tailored for application in near-infrared surface-enhanced Raman spectroscopy

Reproducible synthesis of silver colloidal particles, with diameters of hundreds of nanometres, represents an experimentally rather difficult task although they have revealed a great application potential in e.g. SERS. The newly developed method, based on the reduction of the complex anion [Ag(SO3)2]3-, offers an approach enabling to manage the preparation of silver particles with adjustable average diameters in the interval from 200 nm up to 700 nm due to the choice of the reducing agent and the sulfite concentration. These particles proved their efficiency as substrates for surface enhanced Raman spectroscopy with the excitation in the near infrared region ([small lambda] = 1064 nm) and therefore this newly developed method confirmed the expected application potential.