Anomalous Photoluminescence Quenching in Metallic Nanohybrids

Abstract

We have developed a theory for the photoluminescence and absorption coefficient in nanohybrids made of an ensemble of metallic nanoparticles and the core–shell quantum emitter. The core–shell quantum emitter is made of a quantum emitter core and a dielectric shell. When a probe laser light falls on metallic nanoparticles, electric dipoles are induced in the ensemble. Hence, these dipoles interact with each other via the dipole–dipole interaction. The surface plasmon polaritons are also present in metallic nanoparticles. Excitons in the quantum emitter interact with these surface plasmon polaritons and the dipole–dipole interaction electric fields. Using the quantum mechanical density matrix method, we have developed a theory for the photoluminescence quenching and enhancement, the nonradiative decay rate, and the absorption coefficient for the quantum emitter in the ensemble of metallic nanoparticles. We showed that the nonradiative energy loss is mainly due to the exciton coupling with the dipole–dipole interaction and it is responsible for the power loss in the quantum emitter. This in turn produces anomalous photoluminescence enhancement and quenching. We have compared our theory with experimental data of core–shell CdSe/ZnS quantum dots embedded in an ensemble of Au nanoparticles. A good agreement between theory and experiment is found. We showed that there are an energy shift and an enhancement in the absorption peak due to the dipole–dipole interaction. Finally, we showed that there is the anomalous quenching and enhancement in the photoluminescence spectrum of the CdSe/ZnS quantum dot embedded in the ensemble of Au nanoparticles. This phenomenon also occurs mainly due to the dipole–dipole interaction in the ensemble of Au nanoparticles. These are interesting results and can be used to fabricate nanosensors for applications in nanomedicine and nanotechnology.

Using intracellular plasmonics to characterize nanomorphology in human cells

“…Hence, the particles are surrounded by biological environments with specific dielectric constants, resulting in core-shell nanohybrids. The optical properties of these nanohybrids are changed compared to those of the core parts (metallic particles) [26][27][28] . The hyperspectral technique could provide information on these changes and on their intracellular localization.…”

Study of ultrafast Rabi flopping in colloidal quantum dots at room temperature

“…Excitons in the quantum emitters interact with surface plasmon polaritons via the DDI. The results show that PL quenching and enhancement occur mainly due to the DDI in the ensemble 29 . In our experiment, the main effect on the PL is the interaction between the CQDs and photonic modes (quasi-bound states in the continuum) in an F-P cavity, where the electric field of the F-P modes is strong enough to induce strong coupling in the CQDs.…”

Enhanced Photoluminescence of Gold Nanoparticle‐Quantum Dot Hybrids Confined in Hairy Polymer Nanofibers

“…Hence, a number of experimental investigation, in the past, have been done in this direction to tune the distance between the semiconductor and metal nanoparticles using a number of different spacer materials such as DNA, polypeptides, silica, and synthetic polymers [13,14,29–31] . The past experimental and theoretical studies have also focussed on understanding the effects of inter‐particle distance on PL behaviour [32–35] . For example, Singh et al [34,35] .…”

“…The past experimental and theoretical studies have also focussed on understanding the effects of inter‐particle distance on PL behaviour [32–35] . For example, Singh et al [34,35] . developed a theory for the anomalous PL quenching and enhancement for nanohybrids consisting of an ensemble of MNPs and the core‐shell quantum emitters (QEs) comprising QD core and dielectric shell.…”