Development and applications of long afterglow luminescent materials

Abstract

With the rapid development in display technology, studies of long afterglow luminescent materials for use in different locations, such as highway, railway, airport, ferry and facade of buildings, have become an important area for material scientists and engineers. In general, luminescent composites of different forms are needed for applications in different areas and these composites are usually fabricated by various methods. In our studies, homogenous composites containing phosphorescent alkaline earth aluminates, SrAl2O4:Eu2+,Dy3+, embedded in poly(methyl-methacrylate) (PMMA) were fabricated by hot press and solution casting methods. Their structural properties were investigated by X-ray diffractometry and scanning electron microscopy. Their optical properties were studied by transmittance measurements and emission spectroscopy. In order to get a deeper understanding on the phosphorescent mechanism of these alkaline earth aluminates, glow curves have been measured to determine the activation energies of the trapping levels of the alkaline earth aluminates. The water resistance of these composites has also been assessed by measuring their emission intensities after water emersion. Finally, the mechanical properties of the luminescent composites were also studied using tensile and impact tests. Based on the results of these measurements, the structural, mechanical and optical properties of these luminescent composites have been revealed. After investigating the fabrication techniques and the properties of these composites, these composites have been studied for barricade warning light application. However, due to the protection of intellectual property, the detail as well as the prototype of the barricade warning light will not be disclosed in the content of this thesis.