Preparation And Application Of SERS Substrate Based On Charge Transfer Mechanism

Surface-enhanced Raman Scattering(SERS)effect refers to the phenomenon that the molecule is adsorbed on some nanometer sized conductor Surface or sol,and its Raman scattering signal is significantly enhanced than its body signal.SERS is a single molecule detection technology with fast,nondestructive,high sensitivity and molecular specificity,which can be applied to the fields of surface science,analysis and life science.However,due to the lack of substrates,the application of SERS was limited.It is of great significance to develop a semiconductor substrate with high activity and biological compatibility.The results of this paper are as follows:1.Study on preparation and SERS application of ZrO₂nanoparticles of different sizes by hydrothermal methodZrO₂nanoparticles with different sizes were synthesized by hydrothermal synthesis using three kinds of alcohol amine dispersants.The results of XRD characterization showed that the diameters of diethanolamine,triethanolamine and glycerol were 14.3 nm,17.9 nm and 19.6 nm,respectively,and all of them were tetragonal crystal phases.The results of Raman and scanning electron microscopy were in good agreement with XRD.In addition,the SERS spectral signal intensity of different probe molecules 4-MBA,4-MPY and PATP was 4-MBA>4-MPY>PATP.Taking 4-MBA as the probe molecule,when the size of ZrO₂was 14.3nm,the SERS effect was the best,indicating that there was a dependence between the SERS effect and the base size.2.Study on preparation and SERS application of ZrO₂nanoparticles with different crystal phases by hydrothermal methodTwo kinds of dispersants,diethanolamine and 1,2-dichloroethane,were used to prepare ZrO₂nanoparticles with different crystal type ratios at the ratios of 1:0,4:1,3:1,2:1,1:1,1:2,1:3,1:4 and 0:1,respectively.The results showed that:(1)XRD,Raman,SEM and UV characterization results showed that:With the increase of the proportion of tetragonal phase in ZrO₂and the decrease of the proportion of monoclinic type,its SERS effect was gradually enhanced.When the base was basically pure tetragonal ZrO₂,its SERS effect was the best.The enhancement of b₂mode in probe molecules indicated that the SERS enhancement mechanism of the prepared ZrO2 substrate was mainly chemical enhancement.3.Study on preparation and SERS application of Li,Na,K doped ZrO2 nanoparticles by hydrothermal methodIn order to further improve the SERS enhanced effect of ZrO₂substrate,three kinds of alkali metal(Li,Na,K)ions were used to prepare doped ZrO₂nanoparticles with the doping ratio of 0.5%,1%,3%and 5%for each ion.The results show that all the doped alkali metal ions exist in the lattice of ZrO₂in ionic form.An appropriate amount of doped ions could improve the surface states of ZrO₂nanoparticles.When the doping ratio of the three ions in the same group was 1%,the SERS effect was stronger than that of undoped ZrO₂.The SERS enhanced intensity order of the three ions in the same group was:Li⁺>Na⁺>K⁺.It shows that the smaller the doped ion radius is,the more conducive to SERS enhancement.