Preparation of pristine graphene paste for screen printing patterns with high conductivity

Highlights: • A conductive paste has been formulated based on high pristine graphene loading. • The graphene paste shows good rheology and stability for screen-printing. • The screen-printed pattern has a high conductivity of 9 × 10⁴ S/m and excellent mechanical flexibility. Graphene conductive pastes are poised to apply in making flexible electronics via a screen-printing way because of its excellent electrical and mechanical properties. In this paper, a new formulation of a pristine graphene-based paste was presented consisting of the conductive filler of graphene, a mixed solvent of terpineol, dipropylene glycol methyl ether, cyclohexanone, and the auxiliaries of ethyl cellulose, Span-85 and 1,4-butyrolactone. The paste containing 20 wt% of the graphene was prepared and showed excellent dispersibility and stability. The screen-printed patterns on a polyimide substrate achieved a high conductivity of 9 × 10⁴ S/m and had excellent mechanical flexibility.