Probing the role of oscillator strength and charge of exciton forming molecular J-aggregates in controlling nanoscale plasmon-exciton interactions

In this study, we probe into the roles of exciton oscillator strength and charge of J-aggregates as well as nanoparticle's surface capping ligands in dictating the plasmon-exciton interaction. We systematically compare the plasmon-exciton coupling strengths of two hybrid plexcitonic systems inv...

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Bibliographic Details
Published in:Physical chemistry chemical physics : PCCP 2020-09, Vol.22 (36), p.2499-256
Main Authors: Das, Kamalika, Dey, Jyotirban, Verma, Mrigank Singh, Kumar, Manish, Chandra, Manabendra
Format: Article
Language:English
Subjects:
Aggregates
Capping
Coupling (molecular)
Cyanine dyes
Dyes
Electron micrographs
Excitons
Hybrid systems
Nanoparticles
Oscillator strengths
Polymer matrix composites
Polystyrene resins
Splitting
Strength
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Summary:In this study, we probe into the roles of exciton oscillator strength and charge of J-aggregates as well as nanoparticle's surface capping ligands in dictating the plasmon-exciton interaction. We systematically compare the plasmon-exciton coupling strengths of two hybrid plexcitonic systems involving CTAB-capped hollow gold nanoprisms (HGNs) and two different cyanine dyes, TDBC and PIC, having very similar J-band spectral positions and linewidths, but different oscillator strengths and opposite charges. Both HGN-PIC and HGN-TDBC systems display large Rabi splitting energies which are found to be extremely dependent on dye-concentrations. Interestingly, for our plexciton systems we find that there is interplay between the exciton oscillator strength and the electrostatic interaction amid dyes and HGN-surfaces in dictating the coupling strength. The oscillator strength dominates at low dye-concentrations resulting in larger Rabi splitting in the HGN-PIC system while at high concentrations, a favorable electrostatic interaction between TDBC and CTAB-capped HGN results in larger exciton population of the HGN-surface and in turn larger Rabi splitting for the HGN-TDBC system than the HGN-PIC system even though TDBC has a lower oscillator strength than PIC. The trend in Rabi splitting is just reversed when the HGN surface is modified with a negatively charged polymer, confirming the role of electrostatic interactions in influencing the plasmon-exciton coupling strength. In this study, we probe into the roles of exciton oscillator strength and charge of J-aggregates as well as nanoparticle's surface capping ligands in dictating the plasmon-exciton interaction.
ISSN:1463-9076
1463-9084
DOI:10.1039/d0cp02380a