title: Transparent conductive films consisting of ultralarge graphene sheets produced by Langmuir-Blodgett assembly.
abstract: Monolayer graphene oxide (GO) sheets with sizes ranging from a few to ∼200 μm are synthesized based on a chemical method and are sorted out to obtain four different grades having uniform sizes. Transparent conductive films are produced using the ultralarge graphene oxide (UL-GO) sheets that are deposited layer-by-layer on a substrate using the Langmuir-Blodgett (LB) assembly technique. The density and degree of wrinkling of the UL-GO monolayers are turned from dilute, close-packed flat UL-GO to graphene oxide wrinkles (GOWs) and concentrated graphene oxide wrinkles (CGOWs) by varying the LB processing conditions. The method demonstrated here opens up a new avenue for high-yield fabrication of GOWs or CGOWs that are considered promising materials for hydrogen storage, supercapacitors, and nanomechanical devices. The films produced from UL-GO sheets with a close-packed flat structure exhibit exceptionally high electrical conductivity and transparency after thermal reduction and chemical doping treatments. A remarkable sheet resistance of ∼500 Ω/sq at 90% transparency is obtained, which outperforms the graphene films grown on a Ni substrate by chemical vapor deposition. The technique used in this work to produce transparent conductive UL-GO thin films is facile, inexpensive, and tunable for mass production.
authors.affiliation: Department of Mechanical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
authors.forename: Qingbin
authors.initials: Q
authors.lastname: Zheng
authors.forename: Wai Hing
authors.initials: WH
authors.lastname: Ip
authors.forename: Xiuyi
authors.initials: X
authors.lastname: Lin
authors.forename: Nariman
authors.initials: N
authors.lastname: Yousefi
authors.forename: Kan Kan
authors.initials: KK
authors.lastname: Yeung
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Li
authors.forename: Jang-Kyo
authors.initials: JK
authors.lastname: Kim