The Preparation Of Surface-enhanced Raman Scattering Substrates Based On Silver Halides

Raman scattering spectroscopy is a technology that reflects themolecular structure information. But the signal is very weak. The discovery of Surface-enhanced Raman spectroscopy (SERS) enhanced the Raman signal effectively.SERS requests that the detected molecular must be absorbed on rough metal surface or metal nanoparticles, only in this way can SERS be achieved.In this paper, through the control of experimental conditions, a variety of silver halide-based SERS substrates with different morphologies are prepared. I focus on the AgBr and Ag-AgBr composite system performance substrates and its SERS property.Semipermeablemembrane is used in the first method to get the silver halide-based SERS substrates. Silver nitrate and bromine solution (such as silver bromide, cetyltrimethyl ammonium bromide and so on) are placed on the different side of the semipermeablemembrane.The ions go through the semipermeablemembrane to have chemical reaction so the silverhalides is generated and deposited on the membrane. The morphologies are effected by the control of the reaction time, temperature, the solutionconcentration and the surfactant.In terms of the surfactant CTAB, can provide bromide ions which is required for the reaction. The microstructure of the substrate was dense dendritic morphology.And the enhancement factor is up to105.Hydrazine hydrate is used for the second method. Hydrazine hydrate is dropped while the reaction between the silver solution and bromine solution, part of silver bromide is reduced to silver. The solid substrate is obtained by filtration method or direct precipitation method of the silver and silver bromide complex system. Rhodamine6G and2-aminothiophenol are used as detected molecular to have Raman experiments. The detected limit can reach10-14mol/l. Besides, By the characterization experiments such as scanning electron microscope(SEM),we can see that the substrates have similar morphology and general high SERS signal. Most important of all, the substrates can be stored for as long as twenty-week time. It is a practical SERS substrate.Bacteria such as E.coil is combined with the substrate in method two for Raman experiments. Through the regulator on a variety of experimental conditions,the characterized bacteria SERS can can be measured.It proves that the achievement can be combined with medical and biology.