Design and construction of a sensitive silver substrate for surface-enhanced Raman scattering spectroscopy

A well-designed and new type of sensitive surface-enhanced Raman scattering (SERS)-active substrate is reported in the paper. The process, which is performed by using 5 Å molecular sieves as templates and final removal of the templates, has considerable virtue of enormously enlarging the amount of contact spots between every pair of particles due to the formation of inner planar nanostructures. First, the ammine complexes of silver ions appear to adsorb on the molecular sieves, then reduced and coalescenced to form closed silver layers, and the 5 Å molecular sieves are subsequently removed by using HF to produce nanostructure aggregations. It has the prominent advantages that the SERS peak intensity of the ∼1076 cm−1 band of 4-mercaptophenol (4-MPH) adsorbed on Ag nanoaggreates is about 60 and 30 times greater than when it is adsorbed on silver nanoparticles coated on a glass substrate or on commercially available 2 μm-sized silver (μAg) powders, respectively. The new SERS-active substrate is produced simply and cost-effectively, so it is expected to play a great role in the development of SERS-based analytical devices.