Structural characteristics in long afterglow strontium aluminate compounds: An investigation with Raman and FTIR spectroscopy

Ergene, Arzu (2022) Structural characteristics in long afterglow strontium aluminate compounds: An investigation with Raman and FTIR spectroscopy. [Thesis]

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Europium (Eu2+), dysprosium (Dy3+), and boron (B) co-doped strontium aluminate compounds emitting persistent luminescence (PersiL) are well-known for offering illumination with zero energy consumption making them attractive for use in safety signage and paint. Although B is well known to extend the persistence of luminescence from Eu and Dy co-doped strontium aluminates, it is not clear how B induces the formation of the material structure that supports extreme afterglow. Previous work suggests that B incorporates interstitially into Sr4Al14O25: Eu, Dy. The objective of this dissertation is to elucidate how B directs the atomic arrangements in such compounds. To set the stage, we applied materials characterization tools that reveal information about short-range order and localized environments, FTIR and Raman spectroscopy. Because micro-Raman reveals spatially resolved information at the micrometer scale, it is particularly well suited for analyzing strontium aluminate pigments, which can be produced with micron-sized grains. Eu and Dy co-doped Sr4Al14O25 (S4A7ED) synthesized with 30-40 mol% B2O3 displayed the longest duration of PersiL, and these compositions do not contain the highest amount of the long persistence phases. Instead, an optimal amount of B is necessary for the incorporation of electrically charged, non-bridging oxygen (NBO) into the doped S4A7ED crystal structure. The use of oxide glass forming precursors of Si, P, and Zr during Pechini processing also extended PersiL in S4A7ED compounds and was correlated with structural changes arising from NBO incorporation. Through the experimental evidence revealed in this work, we discovered a new class of long afterglow compounds.
Item Type: Thesis
Uncontrolled Keywords: Persistent Luminescence. -- Strontium Aluminate. -- Raman Spectroscopy. -- FTIR Spectroscopy. -- Energy-Efficient Lighting. -- Phosphor Pigments. -- Israrlı Işıldama. -- Stronsiyum Aluminat. -- Raman Spektroskopisi. -- FTIR. -- Verimli Aydınlatma. -- Fosfor Pigmentleri.
Subjects: T Technology > TA Engineering (General). Civil engineering (General) > TA401-492 Materials of engineering and construction. Mechanics of materials
Divisions: Faculty of Engineering and Natural Sciences > Academic programs > Materials Science & Eng.
Faculty of Engineering and Natural Sciences
Depositing User: Dila Günay
Date Deposited: 17 Apr 2023 13:53
Last Modified: 10 Jul 2023 10:12

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