Tuning The Optical Properties Of Dye Molecules By Hollow Ag@Au Bimetallic Nanoparticles

The localized surface plasmon resonance of metal nanoparticles is usually generated under light irradiation.Based on this effect,nanoparticles can be used for surface-enhanced Raman,surface-enhanced fluorescence,and plasmon-exciton strong coupling phenomena,etc.Among them,the strong coupling between surface plasmon in metal nanostructures and quantum emitters has become a hot spot in the field of quantum optics.In this work,pure Ag nanoprisms or Ag@Au hollow nanoshells deposited by the TDBC molecules are selected.Through the experimental characterization of morphology and spectrum and theoretical simulation of finite-difference time-domain method,the plasmon-exciton coupling was discussed in depth,and the effective tuning of the optical properties of the dye molecules by metal nanoparticles was realized.The research content of this article is divided into the following aspects:1.The Ag nanoprisms were prepared by a seed-based thermal synthetic procedure.The monometallic particles were transformed into bimetallic particles by the Galvanic Replacement Reaction.The TDBC film was wrapped on the surface of particles by the ligand exchange reaction,respectively.2.The results of transmission electron microscope(TEM)?scanning transmission electron microscope(STEM)and absorption spectrum showed that by controlling the adding amount of the seed,the ultrasonic time and centrifugal times,we can effectively tune the size of the particles,and the localized surface plasmon resonance peak positions.Then,the TDBC film was wrapped on the surface of the metallic nanostructures by the ligand exchange reaction and the plasmon-exciton strong coupling can be observed in the complex systems.3.We investigate the strong coupling from TDBC molecules near metal nanoparticles.When TDBC molecules are deposited on pure Ag nanoprisms or Ag@Au hollow nanoshells with the plasmonic resonance peak,matching very closely with the absorption band of TDBC J-aggregates,obvious Rabi splitting can be observed due to the strong coupling regime.Meanwhile,the photoluminescence intensity decreased with the increasing of the temperature verified the decreasing plasmonexciton coupling interaction in the higher temperature.Our experimental results are coincident with the simulation results calculated by finite-difference time-domain method.