Weak exciton–plasmon and exciton–phonon coupling in chemically synthesized Ag/CdSe metal/semiconductor hybrid nanocomposite

A recently developed method to synthesize metal/semiconductor Ag/CdSe core/shell hybrid nanocomposite has been used. Seed of silver nanoparticles was prepared by reduction of silver acetylacetonate organometallic complex using alkyl amine. Different shell thicknesses have been grown, directly on the Ag core, by the organometallic pyrolysis method. Absorption spectroscopy, photoacoustic spectroscopy, High Resolution Transmission Electron Microscopy (HRTEM), emission spectroscopy, and Raman spectroscopy were used to characterize the Ag/CdSe core/shell samples. The effect of Ag plasmon core on the optical properties of CdSe shell is discussed in the weak exciton–plasmon coupling regime. Emission, absorption, and Raman spectra are employed to determine the Huang–Rhys parameter which is found to show that the exciton–phonon is in the weak coupling regime.

► A new chemical method to synthesize Ag/CdSe core/shell nanocomposite is developed. ► The weak coupling of the Ag core plasmon and the CdSe shell exciton is studied. ► Huang-Rhys parameter indicates the exciton - phonon coupling is weak.