Preparation, Characterization, And Application Of Silver Nanosensor Film

Because of the unique optical, magnetic, electrical, and catalytic properties, noblemetal nanoparticles have been paid much attention and widely used in biosensor,diagnosis and treatment of illnesses, water quality test, surface enhanced Ramanspectroscopy (SERS) etc. fields. Therefore, herein, on the basis of previous work fromsome outstanding teams, we aim to continue to develop the application of noble metalnanoparticles, in particular focused on water quality test and SERS. The researchcontents are divided into three parts, and then we will introduce them one by one.We fabricated nanoprism monolayer onto quartz film as a novel nanosensor,which was used to detect the concentration of Cl-, Br-or I-in water. Moreover,by means of etching technology built that the etching rate changes with theconcentration of ion and Logistic fitting equation, the detected ranges of threeions were given, respectively0.3-6.0mM,3.0-70.0uM, and3.0-18.0uM. Inaddition, we found that silver nanoparticles are considerably insensitive to otherions.We constructed a SERS substrate, and the process of the construction is asfollow: firstly using PS as medium, secondly using RIE to fabricate siliconpillar array, thirdly depositing the silver films of different thicknesses (3,5,7,8,9,10nm) onto the silicon pillar, and lastly fabricating Ag nanoparticles underannealing. From UV-VIS spectrum, we observed that silicon pillar showsthe weakest reflection at633nm, in other words, the strongest absorption.Therefore, in this work, the633nm exciting light was utilized to probe whatthickness of Ag film is the most effective for SERS. The final research resultshows the7nm thickness is the best option for SERS, so in the next part7nm is regarded as the default.We dropped10-6M4-MPY onto the SERS substrate constructed in the secondpart and general substrate respectively, and then applied532,633, and785nmexciting light to conduct Raman research. The result shows particles on pillar(POP) possess much stronger SERS signal compared to the general substrate.Besides, we calculated the enhancement factor of POP and general silicon pillar(1.5×106and2.4×105respectively) at the position of Raman peak of4-MPY(1092cm-1)under633nm exciting light. After that, we detected SERS signals of4-MPY of various concentrations and found the lowest value (10-10), whichdemonstrates POP is of favorable SERS enhancement effect. At last, by meansof FDTD, we further confirm that POP presents the stronger strength of theelectromagnetic field.