Preparation And SERS Characteristics Of Colloidal Crystal-plasmonic Composite Structure

The surface plasmon is the collective oscillations produced by the coupling of free electrons and incident light on the metal surface.The surface plasmon is essentially the collective vibrational energy of the energy of the electromagnetic wave into the free electrons of the metal surface.When the frequency of the incident light is equal to the vibration frequency of the surface plasmon,the surface plasmon resonance is generated,which makes the local near field a great enhancement,which also leads to a lot of enhancement of the optical properties.For example,Light transmission,surface Raman scattering,and so on.Since the surface plasmon has a crucial role in enhancing the surface Raman scattering,the surface plasmon is widely used in the field of surface-enhanced Raman scattering,although the precision machining technique is now quite mature,Looking for large area,high performance,low cost SERS base structure is still a hot research.In this paper,the colloidal crystal-metal surface plasmonic composite structure is prepared by self-assembly method,coating and annealing.The metal structure is controlled and its optical properties are tested and analyzed.The potential application of the field of scattering.The main research contents are as follows:1.Monodispersed silica microspheres were prepared by sol-gel method.The synthesis route was a mixture of ethyl orthosilicate(TEOS)and solvent ethanol,added to the mixture of ammonia and solvent anhydrous ethanol Liquid reaction can be two hours.2.On the basis of improving the evaporation method,high quality single-layer silica colloidal crystals were synthesized by self-assembly of silica as colloidal particles.3.A large area of cap-shaped gold nano-shell structure was synthesized by the deposition of magnetron sputtering system on colloidal crystals.4 By adjusting the annealing temperature of the cap-shaped gold shell structure,the metal structure of the gold nanoparticles is gradually discretized.The results show that this treatment has the characteristics of regulating the performance of the gold nanostructure SERS.5.The finite element method(FDTD)is used as the theoretical calculation method to obtain the electromagnetic field distribution of the gold nanoparticles and the gap on the structure.It shows that the discretized nanoparticles and the nanometer gap Play a decisive role in the enhanced adsorption Raman signal.