Optical Absorption Engineering in Stacked Plasmonic Au-SiO2-Pd Nanoantennas
Artikel i vetenskaplig tidskrift, 2012

The nonradiative decay of a localized surface plasmon through absorption of a captured photon and excitation of an energetic electron-hole pair is a potentially very effective way to enhance chemical reactions on metal nanoparticle surfaces, so far limited to Ag (and Au). Here we explore the possibility of efficient and spectrally widely tunable optical absorption engineering based on heterometallic optical nanoantennas. They consist of an optimized antenna element made of Au (or Ag) and a catalytically active second metallic element separated by a thin SiO2 layer. Specifically, we find that stacked Au-SiO2-Pd nanodisk antennas exhibit pronounced local absorption enhancement in the catalytic Pd particle. The effect is caused by efficient power transfer from the Au disk, exhibiting a narrow low-loss resonance and acting as an antenna collecting photons, to the Pd disk due to strong coupling between the two. The Pd element thus acts as receiver that efficiently dissipates energy into electron-hole pairs owing to efficient coupling to intra and interband transitions. In fact, the energy transfer is found to be so effective that the absorption efficiency at a given wavelength can be enhanced up to 6 to 9 times, and the total absorption integrated over a wide spectral range (400-900 nm) up to 2-fold, depending on the antenna dimensions. This finding suggests a novel route toward highly efficient plasmon-enhanced catalysis on widely selectable catalytic metal particle surfaces not limited to the "classic" plasmonic metals Au and Ag.

metals

palladium

Localized surface plasmon resonance

constants

nanoparticles

films

nanoantenna

mechanisms

pd

therapy

absorption enhancement

nanostructures

plasmon

gold

Författare

Carl Wadell

Chalmers, Teknisk fysik, Kemisk fysik

Tomasz Antosiewicz

Chalmers, Teknisk fysik, Kondenserade materiens teori

Christoph Langhammer

Chalmers, Teknisk fysik, Kemisk fysik

Nano Letters

1530-6984 (ISSN) 1530-6992 (eISSN)

Vol. 12 9 4784-4790

Ämneskategorier

Fysik

DOI

10.1021/nl3022187