Preparation Of Metal Nanoparticles And Its Inkjet Printing Research

Modern electronic printing is mostly based on the control of digital information,such as the precise and fine printing of various functional materials on different substrates by inkjet printers to achieve various applications.Among them,nano-metal materials have received extensive attention due to their good electrical conductivity and ductility.Inkjet printing technology has the advantages of environmental protection,low cost,simple process,etc.,and has broad application prospects in the fields of organic light-emitting diodes,solar cells,flexible electronic devices and radio frequency identification.In this paper,conductive ink was prepared by studying the machine construction and working mode of the inkjet printer DMP-3000 produced by FUJIFILM Dimatix to achieve precise printing conductive lines on flexible substrates.The main materials of the conductive ink were nano metal particles,and silver nanoparticles(Ag NPs),copper nanoparticles(Cu NPs)and Cu-Ag core-shell nanoparticles(Cu@Ag NPs)were synthesized by ultrasonic assisted water bath method and oil bath method.A series of related characterizations and tests were performed on the synthesized materials.Subsequently,conductive ink was prepared for inkjet printing,and the electrical properties of the circuit were studied.The details are as follows:(1)Study on the performance of Ag NPs conductive inkjet printing circuitPolyacrylic acid(PAA)is used as a coating agent to prepare Ag NPs by using water-bath method to reduce silver nitrate by triethanolamine.This method can also obtain spherical particles with a particle size of about 20 nm in macro-preparation,and is also excellent in inkjet performance.Ag NPs were synthesized by using Radix Puerariae plant extract via ultrasonic assisted water bath method,and the product was centrifuged and filtered,then formulated into conductive ink and printed on polyethylene terephthalate(PET)substrate.The prepared Ag NPs have a particle size of about 25 nm,uniform monodispersity,and can adhere well to the substrate after being formulated into an ink.The resistivity after thermal sintering is 6.3 μΩ·cm.(2)Study on the performance of Cu NPs conductive inkjet printing circuitCu NPs were synthesized by oil bath method.The selected capping agent was PVP.Experiments show that when four PVPs with different average molecular weights are selected as coating agents,the particle size of Cu NPs prepared decreases with the increase of PVP average molecular weight.The bimodal mixture conductive ink is prepared in a volume ratio of 1:3,and the small-diameter Cu NPs are effectively filled in the gap of the large-diameter Cu NPs,thereby increasing the filling density of the conductive line and improving the conductivity.The optimal resistivity is 20.8 μΩ·cm.(3)Study on the performance of Cu@Ag NPs conductive inkjet printing circuitCu@Ag NPs were prepared in two steps by oil bath method.Cu NPs were prepared by alcohol heating method,and then Ag was coated on the surface of Cu NPs to form core-shell structure.The construction of the core-shell structure effectively exploits the advantages of the two materials.The Cu core greatly reduces the possibility of electromigration and the printing cost.The Ag shell acts as a passivation layer to avoid oxidation of the Cu core.The conductive ink prepared by Cu@Ag NPs printed on the PET substrate had a resistivity of 9.8 μΩ·cm after thermal sintering.