Research On Preparation And Application Of Inkjet Printing With Silver Based Functional Inks

Printed electronics has been widely investigated as a new type of manufacture technics for electronic products due to its advantages of multi-function,lightweight,miniaturization,wide range of materials,low cost and environmental protection.The key of printed electronics lies in the functional inks.Nowadays,the drawbacks of conductive functional ink such as easily clogged nozzle,poor stability,demands of repeated printing procedure and the need of high-temperature sintering are still standing in the way of its further application.To overcome these drawbacks,a particle-free silver precursor functional ink with long-term storage stability,proper printability and efficient catalytic activity has been developed for inkjet printing in this study.The ink was applied to the preparation of conductive lines on rigid and flexible substrate.The main research contents are as follows:(1)A inorganic silver-based functional ink was developed using inorganic silver A as functional precursor,water and alcohols as solvents and additives.The ink has long-term storage stability and satisfactory printability as the surface tension is 32.6 mN/m,the viscosity is 2.6 mPa·s and the parameter Z of ink hydrodynamic characteristic is 8.07.The seed layer pattern obtained by inkjet printing is not conductive,but it can induce electroless copper plating.When the content of silver nitrate in the ink is 0.06 mol/L,it could show high catalytic performance.(2)In order to verify the applicability of the silver nitrate functional ink,the ink was printed on the surface pretreated ceramic substrate and PI substrate by inkjet printing technology,and as the catalytic seed layer for follow-up electroless copper plating.The results show that the size of the metal copper on the ceramic substrate is uniform,the copper layer is flat,the resistivity is as low as 3.74 ??·cm,the adhesion is 11.8 N/cm~2.The capacitor performance of the metal copper layer match with the industrial application.The resulting copper layer on the PI substrate exhibited compact,uniform and well-crystallized structure.The electrical resistivity is as low as 2.81 ??·cm and adhesion on polyimide substrate is as high as 5B category according to the ASTM D-3359.(3)A particle-free silver precursor ink suitable for inkjet printing was developed using organic silver B as functional precursor and organic amine 3 as complex solvent.Long-term storage stability and satisfactory printability of this ink has been proved and it is successfully printed on PI substrate using a inkjet printer.Its efficient catalytic activation for subsequent electroless plating was confirmed by the rapid growth of copper layers,and the resulting copper layer exhibited compact,uniform and well-crystallized structure.The electrical resistivity is as low as 2.80 ??·cm(1.67 times larger than that of bulk copper),and adhesion on polyimide substrate as high as 5B category according to the ASTM D-3359 These results suggest this particle-free precursor ink is of great potential in the field of flexible printed electronics.