Investigation of chemically modified barium titanate beads as surface-enhanced Raman scattering (SERS) active substrates for the detection of benzene thiol, 1,2-benzene dithiol, and rhodamine 6G.

SERS active surfaces were prepared by depositing silver films using Tollen's reaction on to barium titanate beads. The SERS activity of the resulting surfaces was probed using two thiols (benzene thiol and 1,2-benzene dithiol) and rhodamine 6G. The intensity of the SERS signal for the three analytes was investigated as a function of silver deposition time. The results indicate that the SERS intensity increased with increasing thickness of the silver film until a maximum signal intensity was achieved; additional silver deposition resulted in a decrease in the SERS intensity for all of the studied molecules. SEM measurement of the Ag coated barium titanate beads, as a function of silver deposition time, indicate that maximum SERS intensity corresponded with the formation of atomic scale islands of silver nanoparticles. Complete silver coverage of the beads resulted in a decreased SERS signal and the most intense SERS signals were observed at deposition times of 30 min for the thiols and 20 min for rhodamine 6G.