title: Bromination of Graphene: A New Route to Making High Performance Transparent Conducting Electrodes with Low Optical Losses.
abstract: The unique optical and electrical properties of graphene have triggered great interest in its application as a transparent conducting electrode material and significant effort has been invested in achieving high conductivity while maintaining high transparency. Doping of graphene has been a popular route for reducing its sheet resistance, but this has typically come at a significant loss in optical transmittance. We demonstrate doping of few layers graphene (FLG) with bromine as a means of enhancing the conductivity via intercalation without major optical losses. Our results demonstrate the encapsulation of bromine within the FLG, leading to air-stable transparent conducting electrodes with 5-fold improvement of sheet resistance reaching ∼180 Ω/□ at the cost of only 2-3% loss of optical transmittance. The remarkably low trade-off in optical transparency leads to the highest enhancements in the figure of merit reported thus far for FLG. Furthermore, we tune the work function by up to 0.3 eV by tuning the bromine content. These results should help pave the way for further development of graphene as a potential substitute to transparent conducting polymers and metal oxides used in optoelectronics, photovoltaics, and beyond.
authors.affiliation: Division of Physical Sciences and Engineering, Solar and Photovoltaics Engineering Research Center (SPERC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.|Boeing Research and Technology, Seattle, Washington 98124-2499, United States.
authors.forename: Ahmed E
authors.initials: AE
authors.lastname: Mansour
authors.affiliation: Division of Physical Sciences and Engineering, Solar and Photovoltaics Engineering Research Center (SPERC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.|Boeing Research and Technology, Seattle, Washington 98124-2499, United States.
authors.forename: Sukumar
authors.initials: S
authors.lastname: Dey
authors.affiliation: Division of Physical Sciences and Engineering, Solar and Photovoltaics Engineering Research Center (SPERC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.|Boeing Research and Technology, Seattle, Washington 98124-2499, United States.
authors.forename: Aram
authors.initials: A
authors.lastname: Amassian
authors.affiliation: Division of Physical Sciences and Engineering, Solar and Photovoltaics Engineering Research Center (SPERC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.|Boeing Research and Technology, Seattle, Washington 98124-2499, United States.
authors.forename: Minas H
authors.initials: MH
authors.lastname: Tanielian
keywords: bromine; doping; few layers graphene; graphene; transparent conducting electrodes