Tunable Fano Resonance and Plasmon-Exciton Coupling in Single Au Nanotriangles on Monolayer WS2 at Room Temperature

Mingsong Wang; Alex Krasnok; Tianyi Zhang; Leonardo Scarabelli; He Liu; Zilong Wu; Luis M Liz-Marzán; Mauricio Terrones; Andrea Alù; Yuebing Zheng

doi:10.1002/adma.201705779

Tunable Fano Resonance and Plasmon-Exciton Coupling in Single Au Nanotriangles on Monolayer WS₂ at Room Temperature

Adv Mater. 2018 May;30(22):e1705779. doi: 10.1002/adma.201705779. Epub 2018 Apr 16.

Authors

Mingsong Wang¹, Alex Krasnok², Tianyi Zhang³, Leonardo Scarabelli^{4

5}, He Liu⁶, Zilong Wu¹, Luis M Liz-Marzán^{4

7

8}, Mauricio Terrones^{3

6

9

10

11}, Andrea Alù², Yuebing Zheng¹

Affiliations

¹ Department of Mechanical Engineering, Materials Science and Engineering Program, Texas Materials Institute, The University of Texas at Austin, Austin, TX, 78712, USA.
² Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX, 78712, USA.
³ Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16802, USA.
⁴ Bionanoplasmonics Laboratory, CIC biomaGUNE, Paseo de Miramón 182, 20014, Donostia-San Sebastián, Spain.
⁵ Department of Chemistry and Biochemistry, California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
⁶ Department of Chemistry, The Pennsylvania State University, University Park, PA, 16802, USA.
⁷ Ikerbasque, Basque Foundation for Science, 48013, Bilbao, Spain.
⁸ Biomedical Research Networking Center in Bioengineering, Biomaterials, and Nanomedicine, CIBER-BBN, 20014, Donostia-San Sebastián, Spain.
⁹ Department of Physics and Center for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, PA, 16802, USA.
¹⁰ Department of Materials Science and Engineering & Chemical Engineering, Carlos III University of Madrid, Avenida Universidad 30, 28911, Leganés, Madrid, Spain.
¹¹ IMDEA Materials Institute, Eric Kandel 2, Getafe, Madrid, 28005, Spain.

PMID: 29659088
DOI: 10.1002/adma.201705779

Abstract

Tunable Fano resonances and plasmon-exciton coupling are demonstrated at room temperature in hybrid systems consisting of single plasmonic nanoparticles deposited on top of the transition metal dichalcogenide monolayers. By using single Au nanotriangles (AuNTs) on monolayer WS₂ as model systems, Fano resonances are observed from the interference between a discrete exciton band of monolayer WS₂ and a broadband plasmonic mode of single AuNTs. The Fano lineshape depends on the exciton binding energy and the localized surface plasmon resonance strength, which can be tuned by the dielectric constant of surrounding solvents and AuNT size, respectively. Moreover, a transition from weak to strong plasmon-exciton coupling with Rabi splitting energies of 100-340 meV is observed by rationally changing the surrounding solvents. With their tunable plasmon-exciton interactions, the proposed WS₂ -AuNT hybrids can open new pathways to develop active nanophotonic devices.

Keywords: Fano resonance; Rabi splitting; monolayer WS2; plasmon-exciton coupling; plasmonics.