Morphology controllable synthesis of silver nanoparticles: Optical properties study and SERS application

•Different water dosages can produce silver nanoparticles with controllable shapes.•Granule-like silver nanoparticles possess relatively high absorption.•Plate-like particles have relatively high transmittance.•Silver nanoparticles with different shapes show selective SERS enhancement. In this paper, we report the controllable preparation of silver nanoparticles with plate-like and granule-like morphologies using mixed solvent of ethanol and water. The dosage of water was found to be critical on the morphologies and sizes of the final silver nanoparticles. Optical measurements reveal that the plate-like silver nanoparticles possess relatively high transmittance, while the granule-like ones show low transmittance and high absorption. In addition, after binding with rhodanine, the silver nanoparticles exhibit selective enhancement for different bands as SERS substrate. The Raman bands at ca. 660cm−1 is higher for plate-like nanoparticles, while the Raman bands at ca. 1184cm−1 is stronger for granule-like nanoparticles.