Preparation Of Graphene-silver Nanocomposite,microstructure And Electrical Property

Graphene has high electron mobility and good thermal conductivity. In the metal, the electrical conductivity of silver is the best in nature, while the nano-silver has a special electronic structure and huge specific surface area. Both of them have unique properties, therefore the graphene/nano-silver composite will be applied in conductive film, conductive paper, low temperature conductive ink and other fields.Graphene oxide(GO) was prepared by modified Hummers method. The graphene/nano-Ag(RGO/Ag) composite was prepared by a simple one-step chemical method, in which the hydrazine hydrate was used as a reductant. The influence of material structure and heat treatment on electrical conductivity of RGO/Ag composite is investigated. The results indicate that the graphene oxide can be successfully reduced companying with the reduction of silver nitrate and thus the RGO/Ag composite is prepared. The conductivity of the RGO/Ag composite increases significantly through adjusting Ag addition and heat treatment, when the loading amount of GO is below 50 wt%. The sheet resistance of RGO/Ag composite can be reached to 8 mΩ/□, when the loading amount of GO is 16 wt%. However, Ag content and heat treatment have much less effect on the conductivity of the resulting composite, when the loading amount of GO is more than 50 wt%.The graphene/silver citrate ink was prepared, with silver citrate as the Ag source, 1,2-diamine as the complexant, resin A as the binder, span 85 as the dispersant, RGO or graphene JCG-1-2.6 as the functional phase. The influence of binder ratio, silver citrate ratio, graphene ratio, heat treatment, film thickness and types of graphene on properties of graphene/silver citrate ink is investigated. The results indicate that the adhesive property of graphene/silver citrate ink increases significantly through adjusting resin A, but the conductivity decreases. The conductivity of graphene/silver citrate ink increases significantly through adjusting silver citrate and heat treatment, when the loading amount of silver citrate is more than 17.9 wt%. However, heat treatment has much less effect on the conductivity of the resulting ink, when the loading amount of silver citrate is below 17.9 wt%. The conductivity of graphene/silver citrate ink decreases through adjusting RGO, and the adiusting graphene may not help improve the electrical property of graphene/silver citrate ink. The conductivity and adhesive property of the film made by the ink are obtained when the film is treated at 230 °C for 1 h. The graphene/silver citrate ink has good stability.