Green synthesis of AgNPs/reduced graphene oxide nanocomposites and effect on the electrical performance of electrically conductive adhesives

Here we report silver nanoparticles/reduced graphene oxide (AgNPs/rGO) nanocomposites were synthesized by a facile approach based on four green reductants using silver nitrate (AgNO3) and graphene oxide (GO) as a precursor. Field Emission Scanning Electron Microscopy and High Resolution Transmission Electron Microscopy (HRTEM) have been employed to investigate morphological characteristics and exfoliation of reduced graphene oxide (rGO) sheets. The structure of AgNPs/rGO was determined by X-ray diffraction, Raman spectroscopy and X-ray photoelectron spectroscopy. Electrical conductive adhesives (ECAs) were prepared by mixing the micro silver flakes, AgNPs/rGO nanocomposites and epoxy together. To achieve the best electrical conductance, the optimal average size of the silver nanoparticles (AgNPs) in AgNPs/rGO composites is found to be about 20.7 nm. The results show that the resistivity of ECAs consisting of the AgNPs/rGO nanocomposites (0.2 wt% AgNPs/rGO and 69.8 wt% silver flake) was decreased compared with control sample (ECAs filled with 70 wt% silver flake). In particular, the resistivity of ECA filled with glucose-AgNPs/rGO (A-AgNPs/rGO) is 8.76 x 10(-5) Omega cm. In summary, A-AgNPs/rGO was determined to be a promising candidate filler for conductivity improvement of ECAs.