Large-area uniform Ag nanostructure films prepared by a heat reduction method for SERS application

We prepared an active large-area uniform Ag nanostructure film by using the thermally reducing polyvinyl alcohol (PVA)/silver nitrate (AgNO3) composite film for surface-enhanced Raman scattering (SERS) application. The PVA/AgNO3 composite films were spin-coated on the surface of indium tin oxide (ITO) glass, and then were heated to about 500 °C for 10 minutes, forming Ag nanostructure films with a thickness of 100 nm and a large area of 3.24 cm2. The results showed that single layer Ag nano-film had a network structure with a skeleton distribution. Moreover, the large ratio of Ag nanostructure to film area was about 63%. Using melamine molecules as a probe, the maximum enhancement factor of the SERS signal could reach 1149, and the SERS sensitivity and the minimum detection limit were respectively up to 76.91 and 3.85 ng/ml. This method of preparing SERS film can provide a new pathway for the application of low-cost and large-area SERS substrates.