Quenching of photoluminescence in quantum dot, metallic nanoparticles and grapheme hybrid nanomaterials

International Conference and Exhibition on Mesoscopic & Condensed Matter Physics

June 22-24, 2015 Boston, USA

Marek J Brzozowski and Mahi R Singh

The University of Western Ontario, Canada

Posters-Accepted Abstracts: J Material Sci Eng

Abstract :

We investigated the quenching of photoluminescence in a quantum dot (QD)- metallic nanoparticles and metallic grapheme film (QD-MN-G) hybrid system deposited on a dielectric material such as Si. The surface plasmon polaritons (SPPs) are calculated solving the Maxwell equations for the graphene and the dielectric heterostructure in the quasi-static approximation. QDs have excitons which interact with SPPs of graphene-dielectric heterostructure. Photoluminescence (PL) of QD is found by using the quantum density matrix method in the presence of exciton-SPPs coupling. Numerical simulations for the PL spectrum in the QD are performed for (QD-MN-G) hybrid system. It is found that when the exciton energy of the QD is in resonant with the SPP energy the intensity of the photoluminescence is quenched. The PL quenching occurs is due to the transfer of photon energy from the QD to the graphene film and MN due to the exciton-SPP coupling. Furthermore, when the exciton energy is non-resonant with the SPP energy the PL quenching disappears. The energy transfer from the QDs to the graphene film can be switched ON and OFF by mismatching the resonant energies of excitons and polaritons. The mismatching of energies can be achieved by applying external pump lasers or stress and strain fields. Recently Dong et al. and Zeng et al. have measured the PL spectrum of QDs in QD-G hybrid and QD-MN-G hybrid, respectively. In both experiments they have observed the PL quenching. We have compared our theory with these experiments and found a good agreement between theory and experiments. These are interesting findings and they can be used to fabricate switches and sensors by using graphene nanocomposites.

Biography :

Email: msingh@uwo.ca