title: Three-dimensional patterning of solid microstructures through laser reduction of colloidal graphene oxide in liquid-crystalline dispersions.
abstract: Graphene materials and structures have become an essential part of modern electronics and photovoltaics. However, despite many production methods, applications of graphene-based structures are hindered by high costs, lack of scalability and limitations in spatial patterning. Here we fabricate three-dimensional functional solid microstructures of reduced graphene oxide in a lyotropic nematic liquid crystal of graphene oxide flakes using a pulsed near-infrared laser. This reliable, scalable approach is mask-free, does not require special chemical reduction agents, and can be implemented at ambient conditions starting from aqueous graphene oxide flakes. Orientational ordering of graphene oxide flakes in self-assembled liquid-crystalline phases enables laser patterning of complex, three-dimensional reduced graphene oxide structures and colloidal particles, such as trefoil knots, with 'frozen' orientational order of flakes. These structures and particles are mechanically rigid and range from hundreds of nanometres to millimetres in size, as needed for applications in colloids, electronics, photonics and display technology.
authors.affiliation: 1] Department of Physics, University of Colorado, Boulder, Colorado 80309, USA [2] Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, USA.
authors.forename: Bohdan
authors.initials: B
authors.lastname: Senyuk
authors.affiliation: Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, USA.
authors.forename: Natnael
authors.initials: N
authors.lastname: Behabtu
authors.affiliation: Department of Physics, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Angel
authors.initials: A
authors.lastname: Martinez
authors.affiliation: Department of Physics, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Taewoo
authors.initials: T
authors.lastname: Lee
authors.affiliation: Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, USA.
authors.forename: Dmitri E
authors.initials: DE
authors.lastname: Tsentalovich
authors.affiliation: Department of Chemistry, R. E. Smalley Institute for Nanoscale Science and Technology, Rice University, Houston, Texas 77005, USA.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Ceriotti
authors.affiliation: Department of Chemistry, R. E. Smalley Institute for Nanoscale Science and Technology, Rice University, Houston, Texas 77005, USA.
authors.forename: James M
authors.initials: JM
authors.lastname: Tour
authors.affiliation: 1] Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, USA [2] Department of Chemistry, R. E. Smalley Institute for Nanoscale Science and Technology, Rice University, Houston, Texas 77005, USA.
authors.forename: Matteo
authors.initials: M
authors.lastname: Pasquali
authors.affiliation: 1] Department of Physics, University of Colorado, Boulder, Colorado 80309, USA [2] Department of Electrical, Computer and Energy Engineering, Materials Science and Engineering Program, Liquid Crystal Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA [3] Renewable and Sustainable Energy Institute, National Renewable Energy Laboratory, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Ivan I
authors.initials: II
authors.lastname: Smalyukh