(420o) Preparation of Large Area Transparent Conductive Graphene Film Utilizing Langmuir-Blodgett Method

Authors: 
Fan, T., Peking University
Yuan, C., Nanjing University of Posts and Telecommunications
Tang, W., Nanjing University of Posts and Telecommunications
Tong, S., Nanjing University of Posts and Telecommunications
Liu, Y., Peking University Shenzhen Graduate School
Min, Y., Xi'an University of Architecture and Technology
Epstein, A., The Ohio State University

Transparent conductors have been used in a wide variety of photoelectronic and photovoltaic devices, such as flat displays, solar cells, optical communication devices, and solid-state lighting. Graphene, a two-dimensional monolayer of sp2-bonded carbon atoms, has attracted significant interests recently because of the unique transport properties.

Many technical approaches were reported.  However, LB assembly method is a proffered technique that can realize controllable deposition of graphene oxide (GO) in a layer-by-layer manner. The thickness of GO films can be accurately controlled upon repeated deposition, leading to optimized optical and electrical properties of the final products.

We have successfully demonstrated Langmuir-Blodgett assembly of GO, By dispersion graphene or graphene oxide on organic solvent /water, and dropping on water, which the surface pressure and pulling speed form assembly, the film density and the formation of wrinkling can be tailored to produce different topological features. We fabricate flexible transparent graphene film on PET as substrate and preparation of large area graphene film (GFs) with the new technological process. The transparent conductors made from reduced graphene oxide sheets show a high conductivity with sheet resistance of ~650 Ω/sq and transmittance of 90% (2 or 4 layers). The large-scale using graphene transparent conducting film for potential application in solar cells, OLED, are on the way.