Size and structure dependent ultrafast dynamics of plasmonic gold nanosphere heterostructures on poly (ethylene glycol) brushes
Journal article, 2017
We have investigated the plasmonic properties of heterostructures that consist of gold nanosphere (NSs) with average diameters of 60 nm, 40 nm and 20 nm on poly (ethylene glycol) (PEG) brushes by using ultrafast pump-probe spectroscopy experiments. Gold NSs start to behave like gold nanorods with increasing number of immobilization cycles due to the close proximity. Gold NSs immobilized by 3 and 5 deposition cycles show longitudinal modes of plasmon bands at long wavelengths which are characteristic behaviors for gold nanorods. Increasing the number of immobilization cycle also increase relaxation times of samples due to the close proximity. Linear absorption spectra and scanning electron microscopy images show that there are close packing assemblies for heterostructures containing 20 nm gold NSs as the small particle. Ultrafast electron transfer (<100 fs) occurs between transverse and longitudinal modes by exciting the samples at both 520 nm and 650 nm. Further, experimental results indicate that, heterostructures with the small particles have faster relaxation times than other heterostructures due to closed packing of 20 nm gold NSs. (C) 2017 Elsevier B.V. All rights reserved.
absorption
nanostructures
Ultrafast dynamics
optical-properties
arrays
Plasmonics
Materials Science
shape
nanorods
metal nanoparticles
Heterostructures
electron
Optics
Ultrafast
Gold nanospheres
Polymer brushes
dynamics
colloidal gold
spectroscopy
Author
A. Karatay
Ankara Universitesi
Betül Kücüköz
Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry
S. Pekdemir
Erciyes University
M. S. Onses
Erciyes University
A. Elmali
Ankara Universitesi
Optical Materials
0925-3467 (ISSN)
Vol. 73 NOV 83-88Driving Forces
Sustainable development
Subject Categories
Chemical Process Engineering
Chemical Sciences
Roots
Basic sciences
DOI
10.1016/j.optmat.2017.08.008