Preparation Technology And Performance Of Non-Precious Metal-based Surface Enhanced Raman Spectroscopy Substrate

Basing on the controllable modulation for the structure and properties of nanomaterials and taking WO_3-x,WO₂ and Ti₃C₂ as research objects,this work focused on the synthesis,morphology,size control and the assembly technology of these materials with different morphologies,which are prepared in a controlled manner and further used as SERS substrates.The traditional SERS substrates preparing method is just diffusing nanomaterial suspension droplets on a glass plate,which leads to a obviously non-uniformity for the substrate.In this study,the micro-nano printing technology was used and sprayed the obtained nanomaterials into patterned SERS chips,which greatly improved the uniformity.And also,it can adjust the printing density by adjusting the low frequency resonance frequency of the piezoelectric ceramic and changing the spray voltage to achieve component separation.These provide research to promote its practical application.The specific research work is as follows:(1)WO_3-x superstructured nanomaterials are prepared by the solvothermal method using reduced butanol and tungsten tetrachloride(WCl₄)as solvent and tungsten source respectively,under high temperature and pressure.The constructed superstructure was consisted of highly ordered sub-1 nm WO_3-x nanowires and showed multi-component detection capability.In addition to the usual charge-transfer enhancement,such non-metallic WO_3-x displays a unusual dramatic plasmon-enhanced SERS sensing performance with a detection limit of 10^-10 M and a maximum Raman enhanced factor of 8.3×10⁷.More importantly,the prepared WO_3-xSERS chip through micro-nano printing realizes the separation and detection of multi-components simultaneously.(2)WO₂ nanodendritic crystals with small size,uniform particles and highly rough surface are prepared by the solvothermal method.due to the dual boosts of electromagnetic mechanism(EM)enhancement and chemical mechanism(CM)enhancement,the quasi-metallic WO₂ nanodendrites achieve a 8.5×10⁷ level Raman enhanced factor and a 10^-10level detection limit(near single molecule resolution)for probe molecules.From the perspective of application,the separation and detection of multicomponent samples are achieved simultaneously,as these WO₂ nanodendrites were fabricated into patterned SERS chips with“separation column effect”thtough a facile nano-ink spraying method.(3)The highly crystalline monolayer Ti₃C₂ nanosheets with clean surface are synthesized by an improved chemical exfoliation and microwave heating method.The unique structure of nucleus-free-2DEG in Ti₃C₂monolayer provides an ideal transport channel without nuclear scattering,and make the highly crystalline monolayer Ti₃C₂ nanosheets achieve a 3.82×10⁸ Raman enhanced factor and a 10^-11level detection limit for typical environmental pollutants such as azo dyes,trichlorophenol,and bisphenol A.Single-molecule imaging is also realized on the surface of the Ti₃C₂ monolayers,which may be the first time that approximate single-molecule imaging has been achieved on a non-noble-metal SERS substrates.