Preparation And Characterization Of "Pen-on-paper" Flexible Sers Substrates

The flexible SERS substrates are expected to meet the needs of vary test conditions due to their advantages such as wipeable,tailorable,and assemblable,so they have potential applications in the field of on-site and rapid detections.In preparing techniques of flexible SERS substrate,the"pen on paper"method is the simplest and fastest.This method does not require any large-scale equipment and is convenient for experimenters to DIY.It is a low-cost and high-efficiency preparation method for flexible SERS substrates.In this thesis,we successfully prepared a new type of flexible SERS substrate that is heat-resistant,corrosion-resistant,and high laser damage threshold through the selection of flexible substrates and the comparison of the water and organic solvents dispersed"inks".The experimental results obtained are as follows:1.Using water-dispersed silver nano-particles as the"ink",high-performance flexible SERS substrates were written on the nylon 66 filter membrane pretreated by PVA.The detection limit of the substrate for R6G is 10^-12 M,the enhancement factor is1.4×10~9,and the detection limit reaches the single molecular weight level,which has potential values in practical applications.2.Using organic solvent dispersed gold,silver and gold-silver alloy nano-particles as the"inks",the flexible SERS substrates were successfully written on the nylon 66and polytetrafluoroethylene（PTFE）filter membranes.The good capillary effect of the filter membrane fibers makes the SERS performance of the substrates evenly distributed,and the performances do not decrease with the bending of the substrates.3.The flexible SERS substrate written on the PTFE filter membrane has high temperature resistance and laser radiation resistance,and its SERS performance improves with the increase of the proportion of silver in the metallic nanoparticles.Among them,the SERS substrates written with Au₁Ag₈ alloy nanoparticle"ink"can detect R6G with a minimum concentration of 10^-11 M,an enhancement factor of5.4×10~8,and a detection limit of 6.5 ng/cm~2 for malachite green.These substrates also have potential practical applications.