Strong Coupling between Plasmons and Molecular Excitons in Metal-Organic Frameworks

Alexander D. Sample, Jun Guan, Jingtian Hu, Thaddeus Reese, Charles R. Cherqui, Jeong Eun Park, Francisco Freire-Fernández, Richard D. Schaller, George C. Schatz, Teri W. Odom*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

This Letter describes strong coupling of densely packed molecular emitters in metal-organic frameworks (MOFs) and plasmonic nanoparticle (NP) lattices. Porphyrin-derived ligands with small transition dipole moments in an ordered MOF film were grown on Ag NP arrays. Angle-resolved optical measurements of the MOF-NP lattice system showed the formation of a polariton that is lower in energy and does not cross the uncoupled MOF Q1 band. Modeling predicted the upper polariton energy and a calculated Rabi splitting of 110 meV. The coupling strength was systematically controlled by detuning the plasmon energy by changing the refractive index of the solvents infiltrating the MOF pores. Through transient absorption spectroscopy, we found that the lower polariton decays quickly at shorter time scales (<500 ps) and slowly at longer times because of energy transfer from the upper polariton. This hybrid system demonstrates how MOFs can function as an accessible excitonic material for polariton chemistry.

Original languageEnglish (US)
Pages (from-to)7775-7780
Number of pages6
JournalNano letters
Volume21
Issue number18
DOIs
StatePublished - Sep 22 2021

Keywords

  • conformal coating
  • metal-organic framework
  • plasmonic nanoparticle array
  • surface lattice resonance
  • ultrafast spectroscopy

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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