Study On Synthesis And Growth Mechanism Of Ultra-high Aspect Ratio Silver Nanowires

Silver nanowires（AgNWs）are expected to replace the indium tin oxide（ITO）as a new generation of transparent conductive electrodes due to their excellent optoelectronic properties in nanodevices.However,AgNWs prepared by existing methods have severely limited its wide range of applications because of its short length and high particle content.In this paper,AgNWs were synthesized by solvothermal method.The high-purity ultra-high aspect ratio AgNWs were prepared by studying the influencing factors and growth mechanism of nanowires in the synthesis process,and prepared into conductive films.The main contents are as follows:（1）AgNWs with length of 90μm,diameter of 40 nm and length to diameter ratio of more than 2000 were prepared by solvothermal method,and the synthesis yield was80%.The morphology and purity of AgNWs were analyzed by various characterization methods.The effects of different PVP,different reaction temperatures and different concentrations of Fe Cl₃on silver nanowires were investigated.The results show that when the weight ratio of PVP-1300000:PVP-K30 is 2:1,the temperature is 130°C,and the Fe Cl₃content is 0.225 m M,the synthesized AgNWs have the smallest diameter and the best aspect ratio.（2）Using glucose and ethylene glycol as double reducing agents,AgNWs with a length of 30μm,a diameter of 100 nm and a length to diameter ratio of more than 300were synthesized by different reactor filling ratio,PVP content,glucose content and Fe Cl₃concentration.The results showed that the synthesized AgNWs had the best morphology when the filling ratio of the reactor was 50%,PVP was 0.4 g,glucose was0.3 g,and Fe Cl₃concentration was 7.5 m M.At the same time,the effects of the same concentration of Na Cl and Na Br on the diameter of AgNWs were studied.The comparison between the two showed that Na Br has better nucleation control power.（3）Based on the above experimental results,the growth mechanism of AgNWs was discussed.Due to the synergy of complexes,NO^3-and temperature,the AgNWs having a pentagonal cross section are restricted by lateral growth,and gradually grow into AgNWs having a high aspect ratio and a small amount of particles.At the same time,the conductivity and light transmittance of AgNWs and AgNWs/PVB films were further studied.The results show that when the coating times of AgNWs and AgNWs/PVB films is more than 5 times,the conductivity of the film gradually becomes stronger,the conductivity of the film is the worst;The AgNWs film layer coated 5 times had the best light transmittance of 93%.