Surfactant-free carbon black@graphene conductive ink for flexible electronics

The capabilities of conductive ink with both excellent conductivity and flexibility properties are extremely important for the construction of next-generation flexible electronic devices. However, the development of an appropriate ink possessing high conductivity and good dispersity remains a big challenge for ink-jet printing. Here, an original synthesis method of surfactant-free carbon black@graphene (CB@rGO) conductive ink is reported via freeze-drying process and reduction in p-phenylenediamine. The CB@rGO ink unambiguously displays a well-defined and smooth morphology, extremely the CB@rGO conductive particles showing good stability in many solvents. The CB@rGO film exhibited outstanding flexibility which is showed by the durable conductivity after bending 1000 times. Furthermore, it has an excellent conductivity of 714 ± 90 S m⁻¹, and these data increased to 5091 ± 200 S m⁻¹ after the high temperature post-processing increased by 198% compared to the traditional rGO film. Notably, the absence of surfactant in conductive fillers’ dispersing process contributed to the high conductivity of CB@rGO ink compared with the traditional ones.