Facile Doping and Work-Function Modification of Few-Layer Graphene Using Molecular Oxidants and Reductants

Ahmed Mansour, Marcel M. Said, Sukumar Dey, Hanlin Hu, Siyuan Zhang, Rahim Munir, Yadong Zhang, Karttikay Moudgil, Stephen Barlow, Seth R. Marder, Aram Amassian

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

Doping of graphene is a viable route toward enhancing its electrical conductivity and modulating its work function for a wide range of technological applications. In this work, the authors demonstrate facile, solution-based, noncovalent surface doping of few-layer graphene (FLG) using a series of molecular metal-organic and organic species of varying n- and p-type doping strengths. In doing so, the authors tune the electronic, optical, and transport properties of FLG. The authors modulate the work function of graphene over a range of 2.4 eV (from 2.9 to 5.3 eV)-unprecedented for solution-based doping-via surface electron transfer. A substantial improvement of the conductivity of FLG is attributed to increasing carrier density, slightly offset by a minor reduction of mobility via Coulomb scattering. The mobility of single layer graphene has been reported to decrease significantly more via similar surface doping than FLG, which has the ability to screen buried layers. The dopant dosage influences the properties of FLG and reveals an optimal window of dopant coverage for the best transport properties, wherein dopant molecules aggregate into small and isolated clusters on the surface of FLG. This study shows how soluble molecular dopants can easily and effectively tune the work function and improve the optoelectronic properties of graphene.
Original languageEnglish (US)
Pages (from-to)1602004
JournalAdvanced Functional Materials
Volume27
Issue number7
DOIs
StatePublished - Jan 3 2017

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The authors thank Mr. A. R. Kirmani and Dr. G. O. Ngongang Ndjawa from KAUST for valuable discussions pertaining to photoelectron spectroscopy experiments, and Mrs. L. Jamshaid for her logistical support. This work was supported by the King Abdullah University of Science and Technology, by the National Science Foundation (through the MRSEC program, DMR-0820382, and through DMR-1305247), by the Department of the Navy, Office of Naval Research Award No. N00014-14-1-0126, and by Boeing. A.A. is grateful to SABIC for the Career Development SABIC Chair.

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