Strong Coupling between ZnO Excitons and Localized Surface Plasmons of Silver Nanoparticles Studied by STEM-EELS

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• 作者：Jiake Wei ; Nan Jiang ; Jia Xu ; Xuedong Bai ; Jingyue Liu
• 刊名：Nano Letters
• 出版年：2015
• 出版时间：September 9, 2015
• 年：2015
• 卷：15
• 期：9
• 页码：5926-5931
• 全文大小：391K
• ISSN：1530-6992

文摘

We investigated the strong coupling between the excitons of ZnO nanowires (NWs) and the localized surface plasmons (LSPs) of individual Ag nanoparticles (NPs) by monochromated electron energy loss spectroscopy (EELS) in an aberration-corrected scanning transmission electron microscopy (STEM) instrument. The EELS results confirmed that the hybridization of the ZnO exciton with the LSPs of the Ag NP created two plexcitons: the lower branch plexcitons (LPs) with a symmetrical dipole distribution and the upper branch plexcitons (UPs) with an antisymmetrical dipole distribution. The spatial maps of the LP and UP excitations reveal the nature of the LSP鈥揺xciton interactions. With decreasing size of the Ag NP the peak energies of the LPs and UPs showed a blue-shift and an anticrossing behavior at the ZnO exciton energy was observed. The coupled oscillator model explains the dispersion curve of the plexcitons and a Rabi splitting energy of 鈭?70 meV was deduced. The high spatial and energy resolution STEM-EELS approach demonstrated in this work is general and can be extended to study the various coupling interactions of a plethora of metal鈥搒emiconductor nanocomposite systems.