Design And Performance Study Of The SERS Substrate Based On The Coupling Of Ag Nanowire And Au Nanoparticles

Surface Enhanced Raman Spectroscopy (SERS) is a new type of detection method developed in recent decades. SERS combines the advantages of high chemical specificity (vibrational Raman scattering), high sensitivity (electromagnetic and chemical enhancement), and surface selectivity (nearfield enhancement). These advantages not only makes SERS develop rapidly in detection, but also widely used in real-time in situ monitoring variety kinds of chemical reactions.With the development of nanotechnology, many kinds of new SERS substrates with different structure and composition have sprung up. With appropriate SERS substrate, even detection of a single molecule is possible. Designing one-dimensional SERS-active structures that combine both high enhancement and uniformly oriented arrays capable of directional response is critical for prospective chemical sensing applications.This paper introduces the synthesis of single Ag NW@Au NP SERS substrate based on the coupling of the silver nanowires with gold nanoparticles and also a AgNW-AuNP nano device with single "hot spot" has been synthesised by modifing single gold nanoparticles onto the surface of the silver nanowires and the relationship between the SERS peak strength and the number of molecules in the "hot spot" of the nanodevice has been studied. Here is a brief introduction of this paper:Firstly, we reviewed the history, enhancement mechanism and main SERS application in detection of biomolecule, environmental pollutants et al. and monitoring chemical reactions. The synthesis and development of one-dimensional, two-dimensional and three-dimensional SERS substrates as well as research about the SERS performance of silver nanowires have been introduced.In chapter2, we mainly introduce preparation and characterization of the single AgNW@Au NP SERS substrate. The positive charged gold nanoparticles and a negative charged silver nanowires were synthesized through the reference method. After calculation, the gold nanoparticles and silver nanowires were mixed with certain proportion. Gold nanoparticles were modified onto the Ag nanowires by electrostatic adsorption to construct single particle AgNW@AuNP SERS substrate. And the ultraviolet-visible absorption spectrum, scanning electron microscopy (SEM), transmission electron microscopy (TEM) have been used to characterize the synthetic material.In chapter3, the single AgNW@AuNP SERS substrate has been used to detect different concentration of CV. The sensitivity, uniformity and uniformity of this substrate has been studied.The single particle Ag NW@Au NP SERS substrate has also been used to catalysis and monitoring the dimerization of p-NTP to DMAB and the reduction of p-NTP to p-ATP.In chapter4, AgNW-AuNP nanodevice with a single "hot spot" has been prepared by modifying a single gold nanoparticle onto the surface of the silver nanowire with p-ATP as coupling agent and the probe molecule.And the single molecule SERS dectection has been performed on the “hot spot” of the nanodevice.