Richard Kim
Advisor: Dr. William J. Ready

will defend a doctoral thesis entitled,

Fluorescent materials and thin film coatings for temperature sensing applications

On

Wednesday, July 30th at 3:00 p.m.

MRDC Room 4211

and/or

 Virtually via MS Teams

Meeting ID: 247 205 536 422 5

Passcode: Hw2sA2Xp

Committee
            Dr. William J. Ready – School of MSE (advisor)
            Dr. Ellen Yi C. Mazumdar – School of ME
            Dr. Zhitao Kang – School of MSE

      Dr. Yuelan Zhang – GTRI

        Dr. Mark Losego – School of MSE

Abstract

In this work, we develop high-temperature photoluminescent thin-film coatings based on oxides for use on transparent windows in high temperature mechanical systems such as engines and combustors.

The various oxide layers were sequentially deposited onto silicon and sapphire substrates using ion-assisted deposition (IAD), followed by high-temperature annealing to achieve phase formation. The resulting thin films exhibited strong photoluminescence under UV excitation, with the performance of the coatings assessed under high temperature. Advanced characterization techniques, including field-emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), and grazing incidence X-ray diffraction (GIXRD), were employed to analyze the surface morphology and phase composition of the films.

Furthermore, luminescent properties such as photoluminescence (PL) emission and lifetime of these thin films are studied to observe the temperature dependence. By studying the temperature dependent behavior of luminescent properties, luminescent films can potentially be used as a method for measuring temperature across windows.

This research highlights the potential of europium doped yttrium oxide, dysprosium doped YAG, and terbium doped gadolinium aluminum perovskite coatings for enhancing the performance and durability of transparent windows in high-temperature applications.