Energy transfer mediated Rabi splitting in Ag@CsPbCl3 nanohybrids

Abstract

We report a strong exciton (semiconductor)–plasmon (metal) coupling in colloidal Ag@CsPbCl₃ nanohybrids, leading to the emergence of new hybrid states, known as plexcitons. Here, we systematically tuned the energy separation between these hybrid states at zero-detuning energy, the so-called Rabi splitting, apparent from the simultaneous blue and red shift of the exciton and plasmon resonances, respectively. We observe an extremely large Rabi splitting from the absorption measurement, reaching a value as high as 316 meV. The plexciton energies are modelled using a dissipative coupled-oscillator framework, revealing collective coupling strengths that place the system in both the real and strong coupling regimes. We further establish an active energy transfer process between the CsPbCl₃ excitons and Ag plasmons, which underlies the observed strong coupling. The pronounced Rabi splitting observed in colloidal metal–semiconductor nanohybrids establishes a foundation for advancing nonlinear plasmonic technologies.