Inkjet Printing Patterns of Highly Conductive Pristine Graphene on Flexible Substrates

Abstract

Highly conductive pristine graphene electrodes were fabricated by inkjet printing using ethyl cellulose-stabilized ink prepared from pristine graphene. Pristine graphene was generated by exfoliation from graphite using ultrasound-assisted supercritical CO2. The ink, at concentrations up to 1 mg/mL, was stable for more than 9 months and had compatible fluidic characteristics for efficient and reliable inkjet printing. The inkjet printing patterns of the graphene on diverse substrates were uniform and continuous. After 30 printing passes and annealing at 300 °C for 30 min, the printed films developed a high conductivity of 9.24 × 103 S/m. The resistivity of the printed electrodes on the flexible substrates increased by less than 5% after 1000 bending cycles and by 5.3% under a folding angle of 180°. The presented exfoliated pristine graphene and the corresponding efficient methods for formulating the ink and fabricating conductive electrodes are expected to have high potential in applications involving graphene-based flexible electronic devices.

Highly Loaded Mildly Edge‐Oxidized Graphene Nanosheet Dispersions for Large‐Scale Inkjet Printing of Electrochemical Sensors

“…However, replacing graphene by graphene oxide (GO), which is hydrophilic, can lead to high stability aqueous dispersions, but, GO is less conductive (depending on the degree of oxidation of the graphene sheets) than pristine graphene and requires an additional step for its thermal, chemical or photonic reduction . Alternatively„ aggregation of graphene sheets can be reduced or avoided by the addition of stabilizers, which include surfactants and polymers . Using ink stabilizers, such as ethyl cellulose in cyclohexanone, terpineol and diethylene glycol methyl ether, prevent graphene sheet aggregation and increased the solid content of commercial inks to ∼3.4 mg/mL.…”

“…[35] Alternatively" aggregation of graphene sheets can be reduced or avoided by the addition of stabilizers, which include surfactants and polymers. [36,37] Using ink stabilizers, such as ethyl cellulose in cyclohexanone, terpineol and diethylene glycol methyl ether, prevent graphene sheet aggregation and increased the solid content of commercial inks to~3.4 mg/mL. However, the use of stabilizers can result in low film conductivity or even insulating patterns, as the stabilizers electronically insulate the printed particles or create a large inter-particle resistance.…”

Enabling Inkjet Printed Graphene for Ion Selective Electrodes with Postprint Thermal Annealing

“…17 IPG has recently shown tremendous promise in reducing the cost and complexity of graphene circuit fabrication. 18,19 Graphene used in inkjet printing can be synthesized via low cost solvent-exfoliation processes to rapidly produce large batches of graphene or graphene oxide flakes that can be subsequently dispersed and formulated into a printable ink. 20 Furthermore, the ink jet printing process can be used to make microcircuits with line resolution of approximately 60 μm thus eliminating the need for UV lithographic techniques that utilize a prefabricated photomask followed by dry etching of active materials or screen printing techniques that use a prefabricated metal stencil to pattern surfaces with defined circuit geometries.…”

Rapid and efficient intense pulsed light reduction of graphene oxide inks for flexible printed electronics

“…The signicant advantages of this technique involve low cost, few processing steps, additive and digital patterning, low material consumption, and compatibility with various substrates. 4,[13][14][15] In printed materials, graphene has been a prominent contender as a printed metallic component because of its high conductivity, high transmittance, satisfactory stability, and inherent exibility. 16,17 However, there are sequences of issues that still need to be solved.…”