Preparation Of Transparent Electrodes Based On Silver Nanowires And Their Applications In Electrochromic Films

With the development of science and technology,various flexible electronic devices emerge at the historic moment.Flexible transparent conductive film（TCF）is one of the key technologies in wearable and bendable folding electronic devices.With this kind of film can help devices achieve flexible bendable folding characteristics.The flexible conductive film made of silver nanowires（Ag NWs）has better conductivity and transparency compared with other materials.Due to the lack of indium tin oxide（ITO）resources,high market price and difficulty in folding,the flexible transparent conductive film made of silver nanowires is expected to be the best choice to replace ITO.In this paper,silver nanowires with high aspect ratio were synthesized to prepare flexible transparent electrodes,which were applied in flexible electrochromic films.The influence factors of the morphology of silver nanowires,the performance of transparent electrodes and the discoloration performance of the films were systematically studied.Specific research contents are as follows:（1）Silver nanowires were synthesized by polyol method,and the effect of nucleating agent on the morphology of silver nanowires was systematically studied.Using Fe Cl₃and Cu Cl₂ as nucleation control agents,the effects of Fe³⁺and Cu²⁺concentrations on the length of nanowires were compared and studied.Ultra-long Ag NWs with an average length of 200?m and a aspect ratio of 2200 were synthesized.The mechanism of oxidation and corrosion of Fe³⁺during nucleation was observed by scanning electron microscope.On this basis,Cl^-and Br^-were further introduced into the reaction system.By synergistic action with Fe³⁺,the ultrafine Ag NWs have adjustable length with a diameter of 34 nm and aspect ratio up to 2300～3000 were prepared.The flexible transparent electrode based on silver nanowires has good transmittance and electrical conductivity,the transmittance is up to 88%,and the square resistance is as low as 16.5Ω/sq.（2）Ag NWs/PEDOT:PSS composite electrode was prepared by using PET as flexible substrate,Ag NWs as conductive layer and PEDOT:PSS as electrode protective layer.At the same time,we synthesized water-soluble polyaniline sodium polystyrene sulfonate（PANI:PSS）nano-spheres,and prepared Ag NWs/PEDOT:PSS/PANI:PSS electrochromic film by simple drop coating method.The properties of electrode and electrochromic film were studied.Ag NWs/PEDOT:PSS composite electrode has good flexibility,electrical conductivity and transmittance.The introduction of PEDOT:PSS barrier prevents the oxidation and corrosion of Ag NWs and at the same time improves the adhesion between the electrode and PANI:PSS active layer,which avoids the shedding of the active layer from the electrode in electrochemical testing.In addition,electrochromic film can achieve blue-yellow-green color changes,fast response and good stability.