Preparation And Purification Of Ultrathin AgNWs To Make Transparent Conductive Films With Excellent Ultraviolet Radiation Resistance

Silver nanowire transparent conductive films（AgNW TCFs）have shown great promising applications in the field of flexible electronic devices because of their excellent electrical and thermal conductivity,as well as their distinguished optical transparency and flexibility.However,the widespread applications of AgNW TCFs are limited by their poor long-term stability under ultraviolet（UV）light irradiation.On the one hand,the UV light irradiation can easily induce surface plasmon resonance on AgNWs,causing the migration and nucleation of silver atoms for gowth of silver nanoparticles and further diameter expansion of AgNWs.On the other hand,the UV light irradiation can accelerate the vulcanization and oxidation of AgNWs,leading to the formation of corrosion products on the surface of AgNWs,such as silver oxide and silver sulfide.So far,it is still lack of an effective approach to address the UV degradation problem of AgNW TCFs and simultaneously maintain the low sheet resistance and high visible light transmittance.In this thesis,ultrathin AgNWs（UTAgNWs）were firstly synthesized via a modified polyol recipe.Then,the as-obtained UTAgNWs were purified by a dynamic agitation-induced centrifugal filtration method.After adopting a sandwich structure of acrylic resin/UTAgNWs/acrylic resin and a light stabilizer（ferrous sulfate,FeSO₄）,the UTAgNW TCFs with excellent optoelectronic performance and anti-UV irradiation stability were finally fabricated.An optimized film maintained stability for 14 h without degradation under continuous UV light irradiation,and varied only 6.0%for its optoelectronic performance.The remarkable enhancement of the stability against UV light irradiation for AgNW TCFs will facilitate the practical applications in touch panels and displays.The main results obtained in this thesis are as follows:（1）The influence of environmental humidity on the synthesis of UTAgNWs via a polyol recipe was investigated.By controlling the environmental humidity at about35±5%,the amount of particle impurities was dramatically reduced in the synthesis product.And the as-obtained UTAgNWs have an average diameter of 23.1±3.6 nm and aspect ratio up to 1500.（2）The as-obtained UTAgNWs were purified by a dynamic agitation-induced centrifugal method.Large quantities of by-products such as organic additives,nanoparticles and short nanorods were filtered with an addition of 1000 mL ethanol.Simultaneously,large-scale purification of AgNWs was realized and the purification yield is 4 times that of positive pressure filtration.（3）UTAgNW TCFs with excellent UV irradiation resistance were fabricated by adopting a sandwich structure of acrylic resin/UTAgNWs/acrylic resin and using FeSO₄ as a light stabilizer（blend with acrylic）.Several parameters were optimized,such as the coating sequence,the concentration of acrylic resin and the doping amount of FeSO₄.After UV light irradiation for 14 h,the rate of sheet resistance change for the optimized film was only 2.3%,while it reached 418.3%for the pristine UTAgNW TCFs.Importantly,the optimized film showed a good optoelectronic performance,sheet resistance only 64.4±7.6Ω/sq,transmittance as high as 91.2%,haze as low as1.48%,which is better than that of commercial UTAgNW TCFs.