Date of Graduation

Spring 2018

Degree

Master of Science in Materials Science

Department

Physics, Astronomy, and Materials Science

Committee Chair

Robert Mayanovic

Keywords

anisotropic, plasmonic, synthesis, spectra, nanoparticles

Subject Categories

Atomic, Molecular and Optical Physics | Physics | Polymer Chemistry

Abstract

The anisotropic nanostructures of noble metals are of great interest for plasmonic applications due to the possibility of tuning the localized surface plasmon resonance (LSPR) across the UV-VIS-NIR without sacrificing the linewidth as well as to achieve larger local field enhancement. Here, we report a simple and promising fabrication method of anisotropic gold nanostructures film using polystyrene-b-2vinylpyridine (PS-b-P2VP) block copolymers (BCP) as a template. In this approach, PS-b-P2VP spherical micelles were first synthesized as a template followed by selective deposition of Au precursor inside P2VP core of the micelles using ethanol solution of Au salt. Subsequently, heat treatment of the precursor deposited BCP films followed by removal of the BCP template produced anisotropic gold nanostructures of various shapes, such as octahedron, icosahedron, tetrahedron, and triangular prism. A temperature- and time-dependent annealing of the fabricated nanostructures led to the formation of clusters at higher temperatures. Furthermore, measurement of ensemble extinction spectra of the anisotropic Au nanoparticle films showed two broad distinct LSPR peaks; one in the visible range (~ 660 nm), and the other in the NIR range (~ 875 nm). The electrodynamic simulation showed that octahedron and icosahedron nanoparticles are responsible for the LSPR response in the visible; whereas the triangular shapes are responsible for the LSPR response in the NIR. Our work is expected to open up a new direction of synthesis of anisotropic nanostructures of noble metals that can be utilized to tune the LSPR response across the UV-VIS-NIR range using a simple BCP template-based method.

Copyright

© Calbi J. Gunder

Open Access

Share

COinS