AbstractIn this presentation a simple method for the fabrication of cost-effective, on-demand Surface-Enhanced Raman Scattering (SERS) substrates from gold nanoparticle colloids on a glass surface will be discussed. The use of SERS substrates can significantly lower the detection limit for an analyte, which can broaden the analytical applications of Raman spectroscopy. The SERS substrates prepared by evaporating a gold nanoparticle solution on a surface is more attractive method compared with those prepared by nanofabrication, because the former is easier to use and more economical than the latter. But, two main problems need to be addressed in preparing a SERS substrate based on gold nanoparticles: Raman signal interferences from stabilizing capping ligands of nanoparticles and the “coffee-ring” effect. To solve these two issues, my research proposed the use of halide ions to replace the capping ligands and the deposition of gold nanoparticles on a surface in the presence of ethanol vapor in a desiccator under a slight vacuum condition, which could promote homogeneous deposition of nanoparticles. To characterize the gold nanoparticle deposits, absorption spectroscopy and Raman microscopy were primarily used. The plasmon bands of gold nanoparticles were probed using the absorption spectroscopy. The Raman bands of bare gold nanoparticle deposits and those of a Raman dye on the nanoparticle deposits were collected to examine the SERS activity of the prepared surfaces. In this talk the efficacy of my proposed research will be discussed mainly based on these data.