Preparation Of Graphene/Nano Ag Conductive Ink And Research Its Conductivity

Conductive ink is a conductive functional ink which is used for printing and manufacturing electronic products in printing electronics filed.Nano Ag conductive ink is the most commonly used conductive ink in functional printing due to its good conductivity and strong oxidation resistance,however it is expensive and easy to migrate under high electric field.Meanwhile,the processing temperature is so high that printing on flexible substrate is impossible.In this paper,Nano Ag with homogeneous particle size and good dispersibility and graphene/Nano Ag composites loaded with Nano Ag nanoparticles on the surface of graphene are prepared by chemical reduction method and the influence of the change of experimental conditions on the morphology is studied.Nano silver and graphene/Nano Ag composite materials are used as conductive filler to prepare conductive ink.The influence of the content of graphene/Nano Ag and the size of Nano Agon the conductivity of the ink are studied.The follows are main contents:1.Nano Ag dispersion is prepared through using liquid phase reduction method.[Ag?NH3?2]OH is used as silver source which is reduced by glucose under the ethanol system,and PVP is used as a protective agent.The influence of the amount of PVP and the concentration of AgNO₃ on the morphology of Nano Ag particles are investigated.The optimum experimental conditions for preparing spherical Nano Ag particles are determined.It is proved that the Nano Ag particles are well dispersed when the concentration of silver nitrate is 0.1 mol/L and the ratio of PVP to silver nitrate is 1.5:1.The particle size is about 35 nm2.Througth improved Hummers method,graphene oxide with high oxidation degree,perfect crystal type and good dispersibility in ethanol solvent is prepared by using natural graphite as raw material,3.Through simultaneous reduction method,silver ammonia solution and graphene oxide are reduced by glucose reductant under the ethanol system to synthesize graphene/Nano Ag composite.The effects of reaction temperature,the mass ratio of graphene oxide to AgNO₃ and the type of reducing agent on the microstructure of the composites are discussed.As results,Graphene is lamellar and thin.Nano Ag particles arc uniformly distributed on the surface of graphene sheets with uniform particle size ranged from 18 to 40 nm.4.The conductive ink with 60%content of conductive filler is prepared by doping Nano Ag and graphene/Nano Ag composite materials.The effects of graphene/Nano Ag composite materials with different content and different particle size on the conductivity of ink are studied.It is proved that the conductivity of the composites increases gradually while increasing of content of graphene/Nano Ag composites at first.,The conductivity is the best when the content reaches 12%,and then it begins to decrease.Under the conditions that the doping amount of graphene/Nano Ag composites is the same and the ink prepared by the graphene/Nano Ag composite with an average particle size of 18 nm,the conductive properties proved to be the best.The resistivity is about 2.4×10-8 ?·m.