A new perspective for the thermal degradation mechanism of blue BAM

Abstract

Abstract— A new thermal degradation mechanism for blue BAM (BaMgAl10O17:Eu2+) under thermal treatment in the presence of water is proposed. The water can be originated either from the thermal treatment steps, such as organic binder baking steps, or from the atmosphere under which blue BAM is being heated. Under such thermal treatment conditions, water molecules can be easily intercalated into the conduction layers of blue BAM, resulting in not only the depreciation of luminance but also in the emission color change toward green. The intercalated water molecules in the conduction layer, where Eu2+ ions are located along with Ba2+ ions, are strongly associated with Eu2+ ions, creating different coordination environments around Eu2+ ions. In this paper, the details of changes in emission behaviors along with water content in the water intercalated blue BAMs are discussed.

Morphology and Stability of Flux Grown Blue Emitting BAM Phosphors for Plasma Display Panels Applications

“…2. Phosphor particles grown in the presence of LiCl and NH 4 Cl are nearly spherical where as particles grown in the presence of KCl and NaCl are plate like structure. When compared to a phosphor prepared without flux, the growth of particles in the presence of flux is high.…”

“…The mechanism involved in degradation and a green shift in BAM phosphor is not fully understood. [2][3][4][5][6] It is reported that the BAM with excellent crystallinity and stoichiometric composition shows less degradation. 7 It is also found that the morphology of BAM phosphor particles is also one of the contributors for degradation.…”

Effects of Si4+ and B3+ doping on the photoluminescence of BaMgAl10O17:Eu2+ phosphor under UV and VUV excitation

“…According to Refs. [17,18], there are at least three different Eu 2+ sites named with BR, a-BR and mO sites, which have maximal emission at about 2.79 (445 nm), 2.61 (476 nm), and 2.43 eV (511 nm), respectively. Therefore, the change of Eu 2+ distribution in different sites will undoubtedly result in different features of emission spectra, such as peak position and full-width at half-maximum (FWHM), and then lead to different chromaticity coordinates.…”

Optical properties of Si–N doped BaMgAl10O17:Eu2+, Mn2+ phosphors for plasma display panels

“…However, its luminescence intensity is distinctly decreased by heat treatment during the manufacturing process. This deterioration is one of the most significant shortcomings in the application [5][6][7][8][9].…”

“…It is generally agreed that thermal degradation of BAM occurs by oxidation of divalent Eu to its trivalent form due to the adsorbed oxygen atom diffused into the conduction layer accompanied by the oxygen vacancies, several possible interpretations regarding the detailed oxidation mechanism have been reported [5,6,8]. On the other hand, some studies suggested that the thermal degradation was due to a structural change such as an altered local environment for the Eu 2+ ions and the migration of Eu 2+ ions [7,9,10]. In our previous work, it has been confirmed that restricting the migration of Eu 2+ from mirror planes to spinel blocks is an efficient way to improve the thermal stability [11].…”