Preparation Of Flexible Transparent Silver Nanowires Conductive Films And Its Application In Energy Storage Devices

We improved the traditional polyol method to synthetize silver nanowires by optimizing the injection rate of AgNO₃ solution,the concentration of CuCl₂,the concentration of PVP,the reaction temperature,the reaction time and the stirring speed.The nucleation and growth mechanism of the silver nanowires was studied.Finally,a uniform silver nanowire with a diameter of about 120 nm and an average length of 75μm was obtained by one pot method with a yield of 98%.In addition,we controlled the aspect ratio of silver nanowires by changing the solution temperature at the initial stage of seed formation.We further prepared the silver nanowire transparent conductive film,and evaluated its photoelectric properties,After the deposition of PEDOT:PSS,we made the AgNWs/PEDOT:PSS composite electrodes,which had good conductivity and capacitance.Besides,the flexible transparent supercapacitor with sandwiched-structure assembled by the composite electrodes,had ideal electrochemical properties,light transmittance and flexibility.In order to meet the needs of large area printing devices,we used the synthetic silver nanowires as electrical conductors,and formulated a new type of very simple screen-printed silver nanowire ink.The ink contained only water,（hydroxypropyl）methyl cellulose and AgNWs,and had the advantages of good conductivity,no pollution,low cost and so on.After screen-printing the ink,the Ag NWs patterns were not conductive.For the first time,plasma treatment was used to increase the bonding strength between patterns and substrates,and sintered the AgNWs.Then a post treatment process including water washing and thermal annealing was performed to remove cellulose and simultaneously sinter the Ag NW junctions again.We printed the AgNWs honeycomb electrodes followed by spin-coating the doped PEDOT:PSS solution.PEDOT:PSS provided electrochemical storage performance and more conductive channels for AgNWs honeycomb electrodes,It also obstructed the contact between silver nanowires and air,and thus avoided the oxidation of silver nanowires.Besides,the supercapacitor assembled with AgNWs honeycomb/PEDOT:PSS composite electrodes,had an enhanced electrochemical performance compared to the AgNWs/PEDOT:PSS composite electrodes,and also had good transmittance and flexibility.Compared with the sandwiched-structure supercapacitor,the planar supercapacitor had the advantages of small sizes,diversified design and easy integration into microelectronic system.Considering that the screen printed AgNWs electrodes had a three-dimensional network structure and a larger specific surface area,we deposited MnO₂ active material on the AgNWs interdigital electrode.AgNWs not only enhanced the conductivity of MnO₂,but also provided a larger specific surface area for electrochemical reaction,thus improving the capacitive properties of MnO₂ active materials.In addition,the planar supercapacitor based on paper possessed a larger areal specific capacitance compared to that based on PET,the reason was that the paper owned larger specific surface area,which contributed to the electrochemical reaction.