One step synthesis of a hybrid Ag/rGO conductive ink using a complexation–covalent bonding based approach

Hybrid inks formulated using silver nanoparticles with graphene or graphene oxide (GO) have been of significant interest in development of conductive inks for manufacturing of flexible devices and systems. So far all of the methods for synthesizing these inks are based on a two-step process using silver nanoparticles. Herein, we report an Ag/rGO hybrid ink formulated by a one step method through a complexation–covalent bonding process of silver acetate and ethanolamine together with reduced graphene oxide (rGO). Successful dispersion of rGO in the alcohol based solvent was achieved by decorating rGO platelets with ethanolamine. The synthesized ink was just composed of 13.5 wt% of silver and 0.1 wt% rGO but has a favorable electrical performance. A remarkable improvement of resistivity by a factor of above 200 has been observed in Ag/rGO films sintered at 150 °C as compared with that of the Ag films produced using the same formulation and thermal treatment process, while a factor of 10 was observed at 165 °C. The enhancement of conductivity was significant up to the sintering temperature of 230 °C beyond which the difference between the Ag/rGO and Ag films are negligible. The increase of conductivity in Ag/rGO films at low temperatures was attributed to the role of rGO platelets in forming bridges to facilitate charge transfer between the silver particles.