Studies On The Preparation Of Nanosilver/Graphene And Electrical Properties In Electrically Conductive Adhesives

The resistivity of commercial tin-lead solder is about 1×10-5 Ω·cm and that of ECAs is from 10-3 Ω·cm to 10-4 Ω·cm. Therefore, how to low cost and enhance electrical properties is the most improtant problem of electrically conductive adhesives(ECAs). Above all, the purpose of this thesis is to improve the number of conductive path while decrease the dosage of silver flakes, and further increase the electrical properties of ECAs. The content of thesis based on research status as follows.The graphite oxide(GO) was prepared by modified Hummers method. Then four kinds of nanosilver/graphene composite materials were prepared via AgNO3 and GO as initial materials using glucose, trisodium citrate dehydrate, sodium borohydride and sodium hydroxide as reductant, respectively. Scanning electron microscopy(SEM), transmission electron microscopy(TEM), X-ray diffraction(XRD), Raman spectroscopy(Raman) and X-ray photoelectron spectroscopy(XPS) have been employed to investigate morphological and structure of composite materials. ECAs contain the nanosilver/graphene composite material, micro silver flakes and epoxy resin. The resistivity of ECAs was measured by four-point probe station system. The results show that the electrical properties of ECAs doped with nanosilver/graphene reduced by glucose has excellent electrical performance. The resisitivity attains 8.76×10-5 Ω·cm.Silver nanoparticle/graphene was prepared in situ hydrothermal method via silver-ammonia solution and graphene oxide as initial solution with glucose as reductant. Then ECAs was prepared by mixing silver nanoparticle/graphene, silver flakes and epoxy together. The electrical properties of ECAs were tested by four-point probe station system. The results show that the resistivity of ECAs was improved to 1.4×10-4 Ω·cm.The silver nanowires were synthesized by polyol process. Then the silver nanowires/silver nanoparticles/graphene composite material was prepared by hydrothermal method. The electrical properties of ECAs were tested when the conductive filler is composed of silver nanowires/graphene and silver flakes. The results show that the resistivity of ECAs was decreased to 6.03×10-5 Ω·cm.The pure graphene was synthesized by hydrothermal method, then doped graphene into ECAs. The electrical properties of ECAs were tested. The results show that the resistivity of ECAs was decreased to 5.0×10-5 Ω·cm.