Plasmonic gas sensing and multivariate analysis with Au nanoparticles for high temperature applications

Date of Award

1-1-2018

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

College/School/Department

Department of Nanoscale Science and Engineering

Program

Nanoscale Engineering

Content Description

1 online resource (vii, 131 pages) : illustrations.

Dissertation/Thesis Chair

Michael A Carpenter

Committee Members

Kathleen Dunn, Nathaniel Cady, Radislav Potyrailo, Bradley Thiel

Keywords

Gold, Nanoparticles, Nanostructured materials, Plasmonics, Gas detectors

Subject Categories

Materials Science and Engineering

Abstract

Detection of gases emitted from gas turbines such as CO and NO2 and gases relevant to fuel cells such as H2 and CO require materials with high sensitivity, selectivity, and thermal stability. Plasmonic sensing results will be presented using patterned Au nanorods (AuNRs) to detect hydrogen down to 200ppm at 500°C. A new optical detection scheme showing the potential for thermal radiation harvesting with AuNRs in high temperature environments. Additionally, clustering of analyte gas responses will be successfully performed with a subset of the originally collected wavelengths showing the potential for monitoring intensity changes in just a handful of wavelengths instead of hundreds. It will be shown that fabrication of larger AuNRs results in the appearance of higher order plasmon resonance modes, or multipoles, in the absorbance spectrum that can be monitored as a function of time and gas exposure. Polarization measurements as well as electric field map simulations confirm that this higher order resonance is 3rd order. Due to the proximity of the 3rd order resonance to the transverse dipole peak of the AuNRs, both modes were monitored in a single experiment and shown to respond to hydrogen in an air background. Multipolar resonances are promising due to higher figure-of-merits than dipolar resonances and they also enable another peak to be monitored for future multiplexed sensor measurements. Au-CeO2 thin films will be shown to be outstanding candidates for hydrogen detection in fuel cell applications. Reliable, in situ sensing of H2 in fuel cells is very important for better fuel cell performance and since the inlet stream is oxygen-free, requires development of sensors that can function in this environment. It will be shown that Au-CeO2 samples show no saturation until 60% H2 as well as high stability over a 16-day sensing test. Bio-inspired structures modeled after Morpho butterflies have been coated with these Au-CeO2 material stacks and show large wavelength changes in response to both H2 and CO. Additionally, dispersion of these analyte gas responses in both 2D and 3D scores plots will be demonstrated. Testing of the sample for H2 and CO in a background of CO2 is also shown. Future work will be directed towards depositing increased amounts of Au-CeO2 in the active regions.

Comments

Requested ProQuest takedown; no end date

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