Effect of plasmon-exciton interaction in IR luminescence of Ag2S quantum dots near Au nanorods for luminescent thermometry

The actions of plasmon-exciton interaction are of great researchers' interest due to their application in photonic technologies, including the thermo-optical sensorics, photothermal catalysis, thermal metasurfaces for computing systems, optical information coding and recording systems. The work presents the results of studies demonstrating plasmon-exciton interaction in ensembles of colloidal Ag₂S quantum dots (QDs) with an average size of 2.8 nm near metal Au nanorods (NRs), passivated with 2-mercaptopropionic acid under conditions of tuning/detuning spectral resonances in the NRs extinction and QDs luminescence. It is experimentally established that the luminescent properties of Ag₂S QDs dependence on the overlap degree of the luminescence band with plasmon resonance peak. Under spectral resonance conditions, Ag₂S QDs luminescence was quenched without changing the spectral line shape of luminescence band. Based on time-resolved luminescence data, this regularity is the result of photoinduced charge transfer between closely spaced mixture components. Detuning of spectral resonances of plasmon-exciton structure components leads to the luminescence quenching and asymmetry of Ag₂S QDs luminescence band in both short and long wavelengths. Theoretical modeling of the Ag₂S QDs luminescence near Au NRs in the framework of a semiclassical model was realized. It is concluded about the manifestation of the Fano effect, complicated by the average distance dispersion between the components of the plasmon-exciton mixture. Thus, the luminescent properties of Ag₂S QDs near Au NRs can be tuned and used as luminescent sensors for thermoplasmonics applications taking into account their transformation as a result of plasmon-exciton interaction.