Preparation And Properties Of Printed Silver Nanostructures Conductive Inks

With the development of portable electronic devices and flexible wearable electronic devices,people pay more attention to printed electronic technology,which has become a new development direction of electronic manufacturing industry.The characteristics of printed electronic technology produced photoelectricity devices are simple operation,light and light products,flexibility,low cost,personalization,and green environmental protection.As a basic material for making conductive patterns,conductive ink is the key to the development of printed electronics technology and the bottleneck of restricting its further development,whose performance determines the choice of process and the quality of the final product.Firstly,in this paper,we summarize the research progress of several electronic printing processes and conductive inks.Secondly,the liquid-phase chemistry method and the polyol method are used to prepare spherical-like silver nanoparticles,silver nanoflakes,and silver nanowires by optimizing the surface activity and particle growth inhibitors;then the conductive inks for screen printing technology and inkjet printing technology were prepared,respectively,with different morphologies silver nanostructures as conductive filler.The effects of morphology of silver nanostructure,viscosity and surface tension of conductive ink on printing adaptability,microstructure and electrical properties of printed conductive patterns were studied.Finally,paper-based functional circuits were successfully produced using inkjet printing.The specific content of this paper is as follows:?1?Spherical-like silver nanoparticles and silver nanoflakes were prepared by a common liquid phase reduction method,and silver nanowires were prepared by a polyol method.The effects of silver nitrate concentration,surfactant concentration and particle growth inhibitor on the synthesis of silver nanoparticles with different morphologies were studied and then obtained the preparation methods of spherical-like silver nanoparticles,silver nanoflakes and silver nanowires with controllable structure,respectively.The experimental results show that spherical-like silver nanoparticles with an average particle size of 7.8 nm are obtained when the ratio of SN5040?Sodium acrylate?to AgNO₃ is 1:1.Silver nanoflakes with an average thickness of 26.34 nm and the average diameter of111.42 nm are obtained when the AgNO₃ concentration is 8.50 mg·L^-1.Silver nanowires with an average length of 18.91?m and an average diameter of 43.33 nm are obtained when the concentration ratio of Br^-:Cl^-is 8:2.?2?After optimizing various auxiliaries,the conductive inks of screen printing were prepared with the self-made spherical-like silver nanoparticles,silver nanoflakes,and silver nanowires as conductive fillers,respectively.The effects of silver nanostructures with different morphologies on the physical and chemical properties of conductive inks,the electrical and structure properties of screen printing patterns were studied.The experimental results show that conductive inks with hydroxyethyl cellulose as binder and viscosity range of 790⁸90 mPa?s are suitable for screen printing.In the case of the same amount of conductor fillers,the viscosity of the silver nanoflakes ink is slightly higher than that of the spherical-like silver nanoparticles ink,while the surface tension is significantly increased,while the viscosity of the silver nanowires ink is significantly lower than those of the inks prepared with other two kinds of morphologies of silver nanostructures,while the surface tension is significantly increased.When the spherical-like silver nanoparticles mass content is 17.27 wt%,the sheet resistance and RMS of sample are 5.33??sq^-1 and 9.9 nm,respectively.When the silver nanoflakes mass content is 25.30 wt%,the sheet resistance and RMS of sample are 1.83??sq^-1 and 181 nm,respectively.When the silver nanowires mass content is 10 wt%,the sheet resistance and RMS of sample are 2.56??sq^-1 and 33.6nm,respectively.?3?Inkjet printing conductive inks with spherical-like silver nanoparticles and silver nanowires as conductive fillers were prepared.The effects of viscosities and surface tensions of inkjet printing conductive inks on the printing adaptability were studied.The effect of printing parameters on the inkjet printing patterns was studied and the electrical properties of patterns printed with spherical-like silver nanoparticles inks and silver nanowires ink,respectively were discussed.Finally,reactive inks were prepared and the electrical properties and microstructures were studied.The research results show that the inks with viscosity range of ink of 2.8⁹.1 mPa?s and the surface tension of 33.4 mN?m^-1are suitable for inkjet printing.Further,two nozzle holes can improve the printing accuracy.The droplet spacing of the inkjet printing ink has a great influence on the printing pattern accuracy.Too small droplet spacing is not conducive to the printing of small line width.Too large pitch can easily cause the printed circuit to be broken or have semi-circular convex edges.The printing speed has little effect on the printing precision,so the printing speed can be changed appropriately to improve the efficiency.The printing layers has a great influence on the precision of small lines.As the number of printing layers increases,the error value increases.When the mass content of spherical-like silver nanoparticles is 6.91 wt%,the sheet resistance of sample with four layers is 2.71??sq^-1,while the sheet resistance of sample with six layers is 3.19??sq^-1.When silver nanowires mass content is 0.32 wt%,the sheet resistance of sample is 2857??sq^-1.The sheet resistance of sample with eight layers is 11.01?·sq^-1.When the reactive ink concentration is 0.13 g·mL^-1,the sheet resistance of sample is 4.6?·sq^-1,while the sheet resistance of sample with sever layers is 5.15??sq^-1.When the annealing temperature is 130°C,the sheet resistance of sample is 1.35??sq^-1.Sample prepared by reactive inkjet shows a good flexibility and its resistance does not change substantially after bending 3000 times.Finally,inkjet conductive ink is used to print a simple circuit.It shows that inkjet printing technology has a great advantage and potential in printing electronic technology.