Distinctive Enhanced and Tunable Plasmon Resonant Absorption from Controllable Au@Cu₂O Nanoparticles: Experimental and Theoretical Modeling

Abstract

Aiming to explore cooperative interactions between plasmonic metal and semiconductor nanostructures as well as their special plasmon resonant properties, we synthesized Au@Cu 2 O core−shell nanoparticles to demonstrate the dramatic influence of dielectric shell both experimentally and theoretically. The extinction spectra of Au@Cu 2 O nanoparticles with controllable shell thickness from a few layers to over 20 nm show not only a tunable red shift of resonant peak but also distinctive enhanced absorption intensity and peak splitting. We then built an analytical model based on an approximate Mie's theory to interpret their optical features. From this model, we found that the overall optical cross section and absorption portion of Au@Cu 2 O are dramatically enlarged. It has been shown that the proper dielectric shell-coated plasmonic nanoparticles could be very promising, especially for the applications that need effective enhancement of the plasmon resonant absorption.

Facet‐Dependent Optical Properties Revealed through Investigation of Polyhedral Au–Cu2O and Bimetallic Core–Shell Nanocrystals

“…However, these particles do not have a consistent shell morphology. Tian and co‐workers made similar Au‐Cu 2 O nanoparticles with more crystalline shells . The shell morphology was irregular, possibly because of the use of Au cores without a well‐defined shape (Figure b).…”

“…Several groups have reported the formation of metal‐Cu 2 O core‐shell nanocrystals and examined their optical properties as a function of increasing shell thickness . Au, Ag, Pd, and Pt cores have been used.…”

“…Their TEM images are also shown: I, Au nanorods; II‐IV, Au‐Cu 2 O nanocrystals with II) 17, III) 27, and IV) 65 nm shells. Reproduced with permission . Copyright 2011 and 2012, American Chemical Society; Copyright 2013, Royal Society of Chemistry.…”

Coupling Resonances of Surface Plasmon in Gold Nanorod/Copper Chalcogenide Core−Shell Nanostructures and Their Enhanced Photothermal Effect

“…Combination of metal NPs with vacancy‐doped plasmonic semiconductor nanocrystals together will open the access to unexplored phenomena resulting from the coupling between the collective electronic oscillation at surface of metal NPs and the hole oscillation in the neighboring semiconductors . Many metal‐semiconductor hetero‐nanostructures have been synthesized and the plasmonic properties have been investigated . Jiang et al.…”

Light‐Activated Hydrogen Storage in Mg, LiH and NaAlH4

“…In contrast, the deposition of Au nanoparticles on the surface of Mg enhanced the UV absorption and expanded the optical absorption to the visible‐light range with a broad absorption peak at 535 nm. This absorption wavelength is slightly longer than that reported for Au nanoparticles in the same size range (4–18 nm) since the optical properties of Au nanoparticles depend on the surrounding environment …”