Accession Number:

AD1103366

Title:

X-Ray Detection and Strain Sensing Applications of Colloidal Quantum Dots

Descriptive Note:

Technical Report,01 Jul 2018,26 Mar 2020

Corporate Author:

AIR FORCE INSTITUTE OF TECHNOLOGY WRIGHT-PATTERSON AFB OH WRIGHT-PATTERSON AFB

Personal Author(s):

Report Date:

2020-03-20

Pagination or Media Count:

398.0

Abstract:

This thesis investigates CQDs as a fast 10 keV-100 keV x-ray scintillator by functionalizing and experimentally characterizing both the PL spectra and PLdecay of eight varieties of CQDs. In addition, x-ray modeling was conducted to roughly compare scintillating capabilities between different CQDs. Groundwork for future pulsed x-ray scintillator decay tests were discussed. All variants were evaluated for their stability and temporal decay characteristics. Functionalization used four fabrication methods loading the nano-materials into a polymer matrix, dispersion of CQDs as a thin-film on top of quartz,dispersion of CQDs within a 3D printed honeycomb matrix, and drawing them into a PCF. It was found that CQDs dispersed within a 3D printed honeycomb matrix showed CT properties which brought down their temporal PL decay time by at least half. In addition, the blue shifting of the emission wavelength in a CQDSU-8-5 system due to CT could have useful implications in future photonic circuits. The fastest calculated biexponential model THA over the tested structures was seen in the CQD-loaded polymer matrix. Commercially available spherical CQDs showed a faster decay time than the experimentally commercially made NPLs. CdS showed to have the fastest decay time with a calculated biexponential model THA of 545 ps within a CQD-loaded polymer, but its QE was poor due to being a core-only material. InPZnS was the next fastest decaying material with a calculated biexponential model THA of 562 ps within a CQD-loaded polymer with a better QE due to being a core-shell which makes the most promising of the materials studied in this thesis for x-ray scintillating applications. Furthermore, x-ray modeling of alloyed CQD technology showed promise in higher QE for x-ray scintillation than conventional CQDs. In addition to the x-ray application oriented experiments, the stress-strain optical sensing properties of InPZnS were explored.

Subject Categories:

  • Test Facilities, Equipment and Methods
  • Quantum Theory and Relativity
  • Electrical and Electronic Equipment
  • Test Facilities, Equipment and Methods
  • Quantum Theory and Relativity
  • Electrical and Electronic Equipment

Distribution Statement:

APPROVED FOR PUBLIC RELEASE