Power-Dependent\nHybrid Photoluminescence Emission\nof Ag Nanowires on an Ag Film

Nobel metal nanostructures, such as silver nanowires\n(AgNWs), have\nattracted considerable attention due to their extraordinary capability\nto manipulate light-matter interactions at the nanoscale and promising\napplications in various areas. However, the underlying mechanism of\nphotoluminescence (PL) emission of AgNWs on a metal film (NWoF structure)\nis still under debate. Here, we provided an exhaustive investigation\nof the PL behaviors of AgNWs by performing substrate-dependent PL\nimaging, as well as power-dependent PL spectra and photoblinking dynamics\nof single AgNWs on an Ag film with Al<sub>2</sub>O<sub>3</sub> as\na dielectric space. The similar PL spectra among suspension AgNWs,\ncrossed AgNWs on Si/SiO<sub>2</sub> substrate, and single AgNWs on\nthe Ag films confirmed that PL emission from NWoF structures is originated\nfrom AgNWs, rather than Ag films. Three PL peaks from AgNWs on the\nAg film have been attributed to the photoactive Ag nanoclusters, the\nradiative recombination of intraband transitions, and the possible\ngap plasmonic modes, respectively, which have been evidenced by analysis\nof power-dependent PL spectra and photoblinking dynamics. These findings\nmay provide new insight into the PL mechanisms of AgNWs and offer\ninspiration to develop customized plasmonic applications.