Intraband Hot-Electron Photoluminescence from Single Silver Nanorods

Abstract

We report the observation of the undocumented visible one-photon photoluminescence (PL) of single silver nanorods excited by 532 and 633 nm continuous wave lasers with single-nanoparticle spectroscopy. We attribute the PL of silver nanorods to the intraband transition excited hotelectron radiative decay. The PL of silver nanorods closely resembles the corresponding LSPR scattering spectrum, and both are dependent on their aspect ratio. The good correlation between the quantitative PL intensity and the absorption cross section at the excitation wavelength of each nanorod leads to an aspect ratio independent PL quantum yield. The PL quantum yield of silver nanorods is similar to that of gold nanorods (10 −6 ), indicating an efficient intraband excitation of hot electrons. The understanding of the PL mechanism of Ag nanorods points to the high-energy nature of the hot electrons excited via intraband transition, which has important indications in utilizing hot electrons for energy harvesting and photocatalysis.

Synthesis and Optical Properties of Highly Stabilized Peptide-Coated Silver Nanoparticles

“…The selected area of the diffraction pattern (SEAD) of silver nanoprism (Figure 2(d)) indicated that the entire nanoparticle was a single crystalline structure [32][33][34]. The SEAD pattern was indexed according to planes of (111) and (200) reflection, and the crystal structure of silver is FCC on the basis of the d-spacing 2.4 and 2.04 Å.…”

Enhanced Third-Order Optical Nonlinearity Driven by Surface-Plasmon Field Gradients

“…The results are summarized in Fig. 4a [25,[31][32][33], it generally involves electronic transitions within the sp-band, and therefore its spectrum depends sensitively on the temperature-dependent shape of the Fermi-Dirac distribution for the electron gas. Our measured incoherent emission spectra therefore undergo a significant transformation with increasing incident power.…”

Emerging plasmonic nanostructures for controlling and enhancing photoluminescence

“…1b , pathway (iv)). 47 Still plasmons play an important role, helping spatially localise electrons to surface areas around strong near-field regions or out-couple the radiation to the far-field. 44 Although the exact underlying mechanism of PL cannot be clarified further, the crucial role of LSPR in plasmonic nanostructure PL has now been recognised.…”

“…Owing to the highly tuneable LSPR and the lightning rod effect, Au nanorods are the most widely studied nanoparticles, exhibiting the strong PL with a quantum efficiency of ∼10 –6 . 47 , 49 – 51 Therefore, when studying the PL of other nanoparticles, the observed PL intensity is often compared with that of Au nanorods to confirm signal enhancement. The aspect ratio of the rod or the excitation wavelength can also be adjusted to obtain a PL signal of the desired wavelength.…”