PVA-Coated AgNPs/SiO2 for Detection of Gentian Violet with High Sensitivity.

Improving the detection limit of surface-enhanced Raman scattering (SERS) is a significant issue for the design and application of plasmon substrate. It always suffers from the weak affinity of probe molecules on the nanoscale surface, uncontrollable aggregation behaviors of nanoparticles, and strong fluorescence of the detected substance. In this paper, AgNPs/SiO2 substrate is prepared by a rapid thermal annealing method with a mean size of 87.9 ± 30.7 nm. A layer of 5–30 nm PVA (polyvinyl alcohol) film is used as the stabilizer of AgNPs. With PVA coating, AgNPs can improve the detection limit of gentian violet by three magnitudes, compared with the one on undecorated AgNPs which is just 10−5 mol/L. In the sensitive detection using coated AgNPs/SiO2 substrate, PVA possibly plays three significant roles, affinity increaser between gentian violet and silver nanoparticles, fluorescence inhibiter of gentian violet, and stabilizer of Ag nanoparticles. The results provide a modification method for improving SERS sensitivity of plasmon substrate, which uses convenient and low-cost rapid thermal annealing as the patterning method and PVA as the coater, an advantageous technology for plasmon substrate application into trace detection. [ABSTRACT FROM AUTHOR]