Preparation Of Transparent Conductive Film Of Silver Nanowires And Its Heavy Metal Mercury Ions Detection

In recent years,silver nanowires（Ag NWs）have attracted much attention due to their high conductivity and flexibility.Ag NWs transparent conductive film has been widely studied and applied to electronic devices,such as transparent heaters,displays,touch screens,solar cells,organic light-emitting diodes,and wearable devices.There are more and more studies on the ultra-sensitive detection of Raman active molecules,mainly focusing on the development of chemical sensors using surface enhanced Raman scattering（SERS）.The localized surface plasmon resonance（LSPR）of nanoparticles exhibits a considerable red shift when forming nanoparticle aggregates due to the plasmonic coupling between particles.Nanowires based structures show significant SERS effects,and many efforts are directed to the development of high-sensitivity SERS substrates based on metal nanostructures.This thesis mainly studies the preparation of Ag NWs with high aspect ratio,and tests the performance of oxidation resistance,p H resistance,high temperature resistance and aging resistance through Ag NWs surface modification methods.We measured the film resistance by a four-probe tester.XRD,SEM,TEM and other characterization methods were used to analyze its chemical composition and morphology structure.Finally,SERS signals were used to evaluate the performance of detecting heavy metal Hg²⁺.（1）Ag NWs with an aspect ratio of to 1000+were prepared by hydrothermal synthesis method.Effects of different seed inducers on the preparation of Ag NWS and chloride ion on the growth process of Ag NWS were studied.With Cu Cl₂ as seed-inducer,we prepared Ag NWs/glass non-flexible transparent conductive films with transmittance of 93.3%and square resistance of 32 ohm/sq at 550 nm,and Ag NWs/PET flexible transparent conductive films with transmittance of about 90%and square resistance of 58.5 ohm/sq.（2）Ag NWs were modified with Fe Cl₃,Sn Cl₂,and Pb Br₂ solution,and Ag Cl passivation layer,Sn O₂ and Pb O₂ protective layer were successfully formed on the silver nanowires surface,respectively.The four probe tester was used to study the bending resistance and acid resistance of the film alkaline chemical environment,high temperature resistance and anti-aging performance.The results show that the Pb Br₂ modified Ag NWs can exist in 1 M HCl or Na OH solutions for 5 hours.Compared with other films,they exhibit good high temperature resistance at 400℃.After one month of aging test,the resistance change rate is the smallest.After 500 times of bending resistance tests on the PET flexible substrate,it has the smallest square resistance decrease.（3）In order to study reliability in detecting heavy metal Hg²⁺,Ag NWs conductive film was used as the SERS substrate.The optical nanoprobe has reached an ultra-high detection sensitivity of 10^-9 M for the detection of heavy metal Hg²⁺.There is an order of magnitude higher than the highest drinking water standard 10^-8 M specified by the U.S.Environmental Protection Agency（EPA）,and has high repeatability,accuracy and reliability.