Surface enhanced Raman scattering (SERS) substrate and preparation method thereof

Abstract

The invention provides a surface enhanced Raman scattering (SERS) substrate and a preparation method thereof. The SERS substrate comprises a silicon substrate and a chemical modification layer arranged on the silicon substrate. The chemical modification layer includes a hydrophilic silane compound layer with area smaller than 7.5 square millimeter; a hydrophobic silane compound layer surrounding the hydrophilic silane compound layer; and a mono-layer metal nanoparticle layer arranged on the hydrophilic silane compound layer. Under action of the hydrophilic silane compound layer and the hydrophobic silane compound layer, aqueous solution of to-be-detected substance is concentrated on the middle small-area hydrophilic silane compound layer, to improve concentration degree of aqueous solution of the to-be-detected substance. The metal nanoparticle layer realizes more uniform distribution of aqueous solution of the to-be-detected substance. Therefore, the SERS substrate can improve signal intensity and detection sensitivity.

Description

technical field [0001] The invention relates to the technical field of composite materials, in particular to a surface-enhanced Raman scattering substrate and a preparation method thereof. Background technique [0002] Surface-enhanced Raman scattering (SERS) has excellent properties of high sensitivity and spectral accuracy, so it has great application value in the field of chemical and biomolecular detection. In recent years, the localized surface plasmon resonance (SPR) generation excitation and scattering spectroscopy of gold, silver and other nanoparticles has been widely used in the research of SERS. For example, S.Nie and others use nanoscale silver "hot particles" to improve the SERS signal by 10 14 times, thus realizing the detection of single molecules by SERS. However, when the concentration of the analyte in aqueous solution is very small, it cannot be detected even by using such nanoparticles, because the distribution range and distribution uniformity of the a...

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Problems solved by technology

For example, Gentile F., etc. used silicon as the base material, and prepared an ordered array of silicon nanorods by photolithography and electron beam etching, and then deposited silver nanoparticles on the top of the silicon nanorods by surface deposition, and then by soaking Modified the surface of silicon nanorod arrays with octadecylsiloxane to obtain superhydrophobic surface-enhanced Raman scattering substrates (Gentile F., Das G., Coluccio M.L., Mecarini F., Accardo A., Tirinato L. ., Tallerico R., Cojoc G., Liberale C., Candeloro P., Decuzzi P., De Angelis F., Di Fabrizio E.. Ultra low concentrated molecular detection using super hydrophobic surface based biophotonic devices. Microelectronic Engineering 2010, 87 , 798~801.), however, this method is technically difficult for the construction process of the substrate, which is not conducive to popularization; in order to obtain a surface-enhanced Raman scattering substrate with a simple preparation process, Xu F.G. et al. applied chemical methods to construct a three-dimensional zinc oxide nano Array, then silver-plated on the ZnO nano-array, and finally by modifying stearic acid on its surface, that is, hydrophobization treatment to finally get the SERS substrate (Xu F.G., Sun Y.J., Zhang Y., Shi Y., Wen Z.W., Li Z ..Silver nanoparticles coated zinc oxide nanorods array as superhydrophobic substrate for amplified SERS effects.J.Phys.Chem.C, 2011,115,9977~9983.), but this surface-enhanced Raman scattering substrate by hydrophobic However, the concentration of the aqueous solution of the analyte is still low. Taking 5 μL of the aqueous solution of the analyte as an example, the diameter of the microspheres formed on the above-mentioned SERS substrate is about 3.6mm, and the droplets formed at this time are micro The volume of the ball is still relatively large, which will still cause the aqueous solution of the analyte to disperse out of the range of the SERS center hot spot, and the degree of improvement for the SERS signal is still low

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