Journal
ACS NANO
Volume 5, Issue 5, Pages 3724-3735Publisher
AMER CHEMICAL SOC
DOI: 10.1021/nn200082j
Keywords
plasmon resonance; multiphoton photoemission; photoelectron emission; gold nanorod; ultrafast electron dynamics; polarization dependence
Categories
Funding
- Air Force Office of Scientific Research
- National Science Foundation
- National Institute for Standards and Technology
- Direct For Mathematical & Physical Scien
- Division Of Physics [1125844] Funding Source: National Science Foundation
- Division Of Chemistry
- Direct For Mathematical & Physical Scien [1012685] Funding Source: National Science Foundation
Ask authors/readers for more resources
This work investigates plasmon-enhanced multiphoton scanning photoelectron emission microscopy (SPIM) of single gold nanorods under vacuum conditions. Striking differences in their photoemission properties are observed for nanorods deposited either on 2 nm thick Pt films or 10 nm thick Indium tin oxide (ITO) films. On a Pt support, the Au nanorods display fourth-order photoionization when excited at 800 nm, a wavelength corresponding to their plasmon resonance in aqueous solution. A cos(8)(theta) dependence of the photoelectron flux on laser polarization implies photoemission mediated by the dipolar plasmon; however, no plasmon resonance signature Is exhibited over the 750-880 nm range. Electromagnetic simulations confirm that the resonance is severely broadened compared to aqueous solution, indicative of strong Interactions between the Au nanorod and propagating surface plasmon modes in the Pt substrate. On ITO substrates, by way of contrast, sharp plasmon resonances in the photoemission from Individual Au nanorods are observed, with widths limited only by fundamental internal electron collision processes. Furthermore, the ensemble-averaged plasmon resonance for Au nanorods on ITO Is almost unshifted compared to its frequency in solution. Both findings suggest that plasmonk particle-substrate interactions are suppressed in the Au/ITO system. However, Au nanorods on ITO exhibit a surprising third-order photoemission (observed neither in Au nor ITO by itself), Indicating that electrostatic interactions introduce a substantial shift in the work function for this fundamental nanoparticle substrate system.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available