Xiao, Jianan
(2015)
OPTICAL SCATTERING AND SENSITIZATION OF TIO2 NANOWIRES COATED WITH PBS SHELL.
Master's Thesis, University of Pittsburgh.
(Unpublished)
Abstract
Light absorption and transmittance by an array of TiO2 nanorods with different lengths 200-1000nm and diameters 12–22 nm were theoretically studied using the electromagnetic computational technique, finite-difference time domain (FDTD). Then the nanowires were fabricated via the hydrothermal methods and their optical properties were experimentally measured and compared with the theoretical results. The nanowire length and diameter were found to be major parameters in modifying the intensity and the wavelength of the scattered radiation, respectively. In addition, light absorbing behavior of a very thin semiconductor layer (PbS) coated on the surface of highly ordered TiO2 nanorod arrays was simulated. The numerical simulation model is comprised of nanorod arrays grown on a transparent conducting film of glass substrates under front-side illumination. In the FDTD analysis, a transverse electromagnetic (TEM) wave is incident onto PbS or TiO2 first and passing through the barrier layer.
Two monitor planes placed above the electromagnetic source and below nanorod arrays detect the intensity of both the incident wave and the reflected/scattered wave from the TiO2 nanorod structure. The absorption and transmission spectra are determined in the wavelength range 300–700nm as a function of nanorod length, nanorod diameter, and interface barrier layer thickness. In a part of simulation models, PbS shell with the thickness of 10 nm was added on the surface of the nanorod arrays. Results of the electrodynamic simulations were experimentally verified. A significant increase in the light absorption by the PbS-coated nanorods was observed by increasing the nanorod length and decreasing the nanorod diameter. Changes in the barrier layer thickness between the nanorod and the substrate had a negligible effect on the scattering and absorbance spectra.
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| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
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| Date: |
28 January 2015 |
| Date Type: |
Publication |
| Defense Date: |
26 November 2014 |
| Approval Date: |
28 January 2015 |
| Submission Date: |
2 December 2014 |
| Access Restriction: |
1 year -- Restrict access to University of Pittsburgh for a period of 1 year. |
| Number of Pages: |
92 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Materials Science and Engineering |
| Degree: |
MS - Master of Science |
| Thesis Type: |
Master's Thesis |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
light absorption, semiconductors, nanowires, quantum dots |
| Date Deposited: |
28 Jan 2015 16:24 |
| Last Modified: |
15 Nov 2016 14:25 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/23737 |
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