High-Resolution Patterning of Graphene by Screen and Gravure Printing for Highly Flexible Printed Electronics
AssigneesNorthwestern University, Regents of the University of Minnesota
InventorsMark C. Hersam, Ethan B. Secor, Sooman Lim, C. Daniel Frisbie, Lorraine F. Francis, Woo Jin Hyun
Life of this patent
Estimating the term…
Abstract
Graphene ink compositions as can be utilized with gravure and screen printing processes, to provide flexible electronic components with high-resolution printed graphene circuitry.
Claims42
A method of preparing a graphene ink composition, said method comprising:
- exfoliating graphene from a graphene source material with a medium comprising an organic solvent and a cellulosic polymer at least partially soluble in said organic solvent;
- contacting at least a portion of said exfoliated graphene medium with an aqueous medium to concentrate exfoliated graphene in a composition comprising graphene and a said cellulosic polymer;
- contacting said graphene-cellulosic composition with a hydrophobic fluid comprising an ink solvent and a dispersion solvent;
- and
- removing said dispersion solvent, to provide a graphene ink composition comprising a solids concentration and viscosity.
A method of preparing a graphene ink composition, said method comprising:
- exfoliating graphene from a graphene source material with a medium comprising an organic solvent selected from ethanol and dimethylformamide, and an ethyl cellulose;
- contacting at least a portion of said exfoliated graphene medium with an aqueous medium to concentrate exfoliated graphene in a composition comprising graphene and a said ethyl cellulose;
- contacting said graphene-cellulose composition with a hydrophobic fluid comprising an ink solvent and a dispersion solvent;
- and
- removing said dispersion solvent, to provide a graphene ink composition comprising a solids concentration and viscosity.
A gravure printing graphene ink composition, said composition comprising non-oxidized graphene, a hydrophobic fluid component and an ethyl cellulose, said composition comprising a graphene-ethyl cellulose solids concentration of about 5% to about 10% w/v and a viscosity of about 0.1 to about 1.0 Pa·s.
A screen printing graphene ink composition, said composition comprising non-oxidized graphene, a hydrophobic fluid component and an ethyl cellulose, said composition comprising a graphene-ethyl cellulose solids concentration of about 10% to about 20% w/v and a viscosity of about 5 to about 100 Pa·s.
A method of preparing a silicon screen printing stencil, said method comprising:
- providing a silicon wafer comprising a thickness dimension of about 120 μm or less, said dimension providing said wafer mechanical flexibility sufficient for screen printing;
- applying a photoresist composition to said wafer;
- contacting said photoresistive wafer with a photomask comprising a pattern of openings therethrough;
- exposing said photoresist composition to UV light in a pattern defined by said photomask;
- removing said mask and etching said wafer to provide said pattern of openings therethrough;
- and
- removing said photoresist composition, to provide a silicon screen printing stencil.
Dependencies are inferred from the claim text.