Inkjet\nPrinting Patterns of Highly Conductive Pristine\nGraphene on Flexible Substrates

Abstract

Highly\nconductive pristine graphene electrodes were fabricated\nby inkjet printing using ethyl cellulose-stabilized ink prepared from\npristine graphene. Pristine graphene was generated by exfoliation\nfrom graphite using ultrasound-assisted supercritical CO₂. The ink, at concentrations up to 1 mg/mL, was stable for more than\n9 months and had compatible fluidic characteristics for efficient\nand reliable inkjet printing. The inkjet printing patterns of the\ngraphene on diverse substrates were uniform and continuous. After\n30 printing passes and annealing at 300 °C for 30 min, the printed\nfilms developed a high conductivity of 9.24 × 10³ S/m.\nThe resistivity of the printed electrodes on the flexible substrates\nincreased by less than 5% after 1000 bending cycles and by 5.3% under\na folding angle of 180°. The presented exfoliated pristine graphene\nand the corresponding efficient methods for formulating the ink and\nfabricating conductive electrodes are expected to have high potential\nin applications involving graphene-based flexible electronic devices.