Prof. ZHAO JingDepartment of Chemistry, University of Connecticut
ROOM 9004, HefeiNationalLaboratoryBuilding
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. Particularly, we study plasmon-exciton interaction of single QDs near metal nanoparticles. When QDs are placed near Au nanoparticles, their exciton/multiexciton emission lifetimes and quantum yields are modified. At the single QD level, we found that biexciton emission of the QDs near Au nanoparticles was enhanced, and the extent of enhancement dependent on the excitation wavelength. The emission of single QDs changes from photon antibunching to bunching by exciting the QDs close to the plasmon resonance. These studies suggest that plasmonic structures can be used to modify the exciton/multiexciton emission efficiency of QDs. On the other hand, strong coupling in hybrid metal-semiconductor nanostructures could lead to splitting in the dark-field scattering and also fluorescence spectra due to the rapid energy exchange between plasmon and exciton. Using correlated single-particle spectroscopy and electron microscopy, strong coupling was observed in Au-QD-Au sandwiched nanostructures.
Hefei National Laboratory for Physical Sciences at the Microscale
Address: University of Science and Technology of China, No.96, JinZhai Road Baohe District, Hefei, Anhui, 230026, P.R.China.