| Recently,the utilization of printed electronic technology to fabricate electronic devices has become more and more popular.Therefore,increasing attention has been paid to the conductive ink which is a key component in this technology.Nano-metallic materials have become the key material of conductive ink because of their excellent conductivity and stability.At present,commercial and reported nano-Ag and nano-Cu conductive inks still have many problems including environmental pollution,complicated preparation,and high resistivity of printed circuit.In this thesis,by using chemical synthesis method and taking organic matter as the main component,air-stable nano-Ag and nano-Cu were synthesized under atmospheric conditions.X-ray diffraction,TEM,SEM and other characterization means were used to study characterizations of nano-metallic particles.Conductive ink consisting of nano-metallic particles was prepared.The electrical properties of printed circuits and their potential applications in the field of electronic device manufacturing were explored.The main research results are described as follows:(1)The preparation of sliver nanoparticles.Air-stable silver NPs with an average of 50 nm were synthesized with silver nitrate as precursor,sodium hypophosphite as reducing agent,polyvinylpyrrolidone(PVP)and Cetyltrimethylammonium Bromide(CTAB)as protective agent.And 15 nm of silver NPs were produced with silver nitrate as precursor,triethanolamine as reducing agent and sodium polyacrylate as protective agent.Due to the smaller silver NPs require lower sintering temperature,in complex nano-silver conductive ink,the 15 nm of silver NPs was selected as the conductive particles.(2)Deionized water,ethylene glycol and glycerol were selected as mixed solvents to prepare nano-silver conductive ink.Seting up the parameters of ink-jet printer and printing conductive line on the base of photo paper.The inking process is smooth,without tail breaking and ink accumulation,and the edges of conductive printed line is smooth and uniform.(3)The electrical properties of printed conductive traces were investigated.At different sintering temperatures,it was found by SEM that the nano-silver particles were deformed,melted and joined together to form a conductive path as the sintering temperature increased.After sintering at 160 ° C for 30 min,the resistivity reached 14.18 uΩ·cm.The effect of the number of printed layers on the film thickness and resistivity of the printed circuit was discussed.As the number of layers increased,the film thickness increased non-linearly,and the influence on the resistance was small after 14 layers.(4)The mechanical properties of paper-based printed conductive traces were investigated.The bending test and the crimping test were carried out,and the results showed that the sintered wire was in close contact with the substrate and had good mechanical properties.The working circuit composed of the paper-based conductive circuit,the power supply and the LED can drive the 3 V LED lamp to work normally under the working power of 3 V,which indicates that the nano silver conductive ink has high practicability.(5)Nano-copper particles with a particle size of about 7 nm were prepared by using copper sulfate pentahydrate as precursor,hydrazine hydrate as reducing agent and polyvinylpyrrolidone(PVP)as protective agent.Deionized water,ethanol,ethylene glycol and glycerol were selected as mixed solvents,and the proportion of each solvent was adjusted to prepare nano-copper conductive ink with moderate viscosity.(6)The conductive line was directly written on the photo paper using a pen with nano-copper conductive ink,and the resistivity reached 15.56 uΩ·cm after sintering at 160 °C for 2 h.The stability of nano-copper conductive ink was studied.After the nano-copper conductive ink placed for a long time was prepared into a conductive line,the resistivity of the circuit changed little.The nano-copper conductive ink has high practicability. |
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