Gate-tunable modulation of the optical properties of multilayer graphene by the reversible intercalation of ionic liquid anions
Abstract
We demonstrate a substantial modulation of the optical properties of multilayer graphene (∼100 layers) using a simple device consisting of a multilayer graphene/polymer electrolyte membrane/gold film stack. Applying a voltage of 3–4 V drives the intercalation of anion [TFSI]− [ion liquid diethylmethyl(2-methoxyethyl)ammonium bis(trifluoromethylsulfonyl)imide [DEME][TFSI]] resulting in the reversible modulation of the properties of this optically dense material. Upon intercalation, we observe an abrupt shift of 35 cm−1 in the G band Raman mode, an abrupt increase in FTIR reflectance over the wavelength range from 1.67 to 5 μm (2000–6000 cm−1), and an abrupt increase in luminescent background observed in the Raman spectra of graphene. All of these abrupt changes in the optical properties of this material arise from the intercalation of the TFSI− ion and the associated change in the free carrier density (Δn = 1020 cm−3). Suppression of the 2D band Raman mode observed around 3 V corresponds to Pauli blocking of the double resonance Raman process and indicates a modulation of the Fermi energy of ΔEF = 1.1 eV.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Sep 06, 2022
- Source ID
- 10.1063/5.0093651
Entities
People
- Haley Weinstein
- Han Wang
- Indu Aravind
- Jiangbin Wu
- Jonathan Habif
- Ruoxi Li
- Stephen B Cronin
- Zhi Cai
Organizations
- Air Force Office of Scientific Research
- Army Research Office
- National Science Foundation
- United States Department of Energy
- University of Southern California