Seminar: Dr. Jing Zhao, Associate Professor, Department of Chemistry, University of Connecticut
March 16, 2023
4:00 PM - 6:00 PM
Seminar:
Abstract: Metal and semiconductor quantum dots (QDs) exhibit unique size and composition dependent optical properties. The key elements that determine their optical properties are localized surface plasmon resonance in metal nanoparticles and excitons in quantum dots. In my research, we study plasmon-exciton interactions. In part I, when single QDs are placed near Au nanoparticles, their exciton/multiexciton emission lifetimes and quantum yields are modified. And the enhancement in biexciton emission and shortening of exciton lifetime depends on the excitation wavelength. These studies suggest that plasmonic structures can be used to modify the exciton/multiexciton emission efficiency of QDs. In part II, we created strongly coupled Au-QD-Au nanosystems using colloidal assembly. The sandwiched nanostructures exhibit peak splitting in both the dark-field scattering and fluorescence spectra due to the formation of hybrid plasmon-exciton states. Theoretical simulations revealed that the strong coupling occurred between the octopolar mode of plasmon and the excitons. In part III, hybrid metal-semiconductor nanostructures were synthesized and used as photocatalysts. Time-dependent fluorescence and ultrafast transient-absorption spectroscopy were applied to study the exciton recombination and charge-separation process in these nanomaterials.
Date posted
Feb 1, 2023
Date updated
Feb 1, 2023