Kinetic Ionic Permeation and Interfacial Doping of Supported Graphene
Jia, Xiaoyu (University of Mainz)
Hu, Min (University of Science and Technology of China)
Soundarapandian, Karuppasamy (Institut de Ciències Fotòniques)
Yu, Xiaoqing (Max Planck Institute for Polymer Research)
Liu, Zhaoyang (Max Planck Institute for Polymer Research)
Chen, Zongping (Max Planck Institute for Polymer Research)
Narita, Akimitsu (Max Planck Institute for Polymer Research)
Müllen, Klaus (Max Planck Institute for Polymer Research)
Koppens, Frank (Institut de Ciències Fotòniques)
Jiang, Jun (University of Science and Technology of China)
Tielrooij, Klaas-Jan (Institut Català de Nanociència i Nanotecnologia)
Bonn, Mischa (Max Planck Institute for Polymer Research)
Wang, Hai I. (Max Planck Institute for Polymer Research)

Date:	2019
Abstract:	Due to its outstanding electrical properties and chemical stability, graphene finds widespread use in various electrochemical applications. Although the presence of electrolytes strongly affects its electrical conductivity, the underlying mechanism has remained elusive. Here, we employ terahertz spectroscopy as a contact-free means to investigate the impact of ubiquitous cations (Li, Na, K, and Ca) in aqueous solution on the electronic properties of SiO-supported graphene. We find that, without applying any external potential, cations can shift the Fermi energy of initially hole-doped graphene by ∼200 meV up to the Dirac point, thus counteracting the initial substrate-induced hole doping. Remarkably, the cation concentration and cation hydration complex size determine the kinetics and magnitude of this shift in the Fermi level. Combined with theoretical calculations, we show that the ion-induced Fermi level shift of graphene involves cationic permeation through graphene. The interfacial cations located between graphene and SiO electrostatically counteract the substrate-induced hole doping effect in graphene. These insights are crucial for graphene device processing and further developing graphene as an ion-sensing material.
Grants:	Ministerio de Economía y Competitividad SEV-2017-0706 Ministerio de Economía y Competitividad SEV-2015-0522 European Commission 804349
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Graphene ; Terahertz spectroscopy ; Doping ; Ionic permeation
Published in:	Nano letters, Vol. 19, Issue 12 (December 2019) , p. 9029-9036, ISSN 1530-6992

DOI: 10.1021/acs.nanolett.9b04053
PMID: 31742413

8 p, 2.9 MB

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Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > Catalan Institute of Nanoscience and Nanotechnology (ICN2)
Articles > Research articles
Articles > Published articles