Theory of Luminescence

Effect of Reheating and Quenching on the Cathodoluminescence Intensity of Free Lime in Steelmaking Slag

“…Besides, another study reported an absorption band at 420 nm related to 6 A 1g → 4 T 1g transition for Mn 2+ ions in CaO (Feng et al, 2016). Based on the reported emission and absorption bands for CaO and the general mechanisms (Marfunin, 1979;Yacobi & Holt, 1990;Blasse & Grabmaier, 1994;Gribkovskii, 1998;Gaft et al, 2005), we propose a possible mechanism that can explain why the increase of defects in free lime enhances its CL peak intensity at 600 nm (Fig. 5).…”

Intercrystalline distal-effect on the afterglow phenomenon in photoluminescent SrAl2O4:Ce(III), Ln nanotube growth

“…Also an emission intensity is varied during crystal phase transformation. Qualitative performance of SrAl 2 O 4 :Ce 3+ , Dy 3+ , Eu 2+ polymorphs during the afterglow phenomenon reveals an increase of d (α−α) < d (β−γ ) < d (β−β) distal series by the host phase transformation, α-monoclinic, elucidating an old concept of the alterations from the phosphorescence to the fluorescence [8,9]. The energy transferred between DAPs has been strongly reduced by the weak interaction between these luminescent centres with a physical limitation for electrons (de)trapping and (re)combining during the spatial separation of DAPs after host phase transformation to PL-SNT:Ce(III), Ln and β-hexagonal structures in post-annealed conditions.…”

“…Unusually, such treatment initiated SrAl 2 O 4 :Ce 3+ , Dy 3+ , Eu 2+ rolling-up and a successful formation of γ -nanotubes is commenced at ∼1273-1473 K. The nanotubes of 90 nm in diameter and 650 nm in length are shown in TEM and SEM micrographs, figure 2. A substantial mesoporosity is noted, that has been produced due to O 2− vacancies involving typical defects at the 2d sites [8,9] (because all samples were postannealed in an air atmosphere). Energy dispersive x-ray (EDX) spectroscopy indicates the presence of rare-earth elements in all heat-treated samples, figure 2(b).…”

“…Herein, a correlation between the changes in the afterglow phenomenon and the polymorphism is attributable to an 'intercrystalline distal-effect', d, defined as a geometrical influence of the host lattice structure (morphology, size, shape, distance and distribution of crystals). The intercrystalline parameter prevails over the interatomic distance between the donor and acceptor pairs (DAPs) in the dependence of the recombination time [9], because the spatial limitation for energy transfer is far larger in β-γ structures. Attributing d to the nanoscale, the lifetime scale changes with respect to the afterglow phenomenon along with the equation ( 1):…”

Using of Photoluminescent Tile for Evacuation of the Buildings During Electrical Failure

“…Photoluminescence (PL) is excited by electromagnetic radiation with short-wavelengths such as ultraviolet light [3]. Inorganic luminescent materials can be divided in two classes [4]: (1) those that absorb light (pigmented) and (2) absorption and emission characteristics of that solid. Phosphors in the strontium aluminates system activated with europium (Eu) and dysprosium (Dy) has a wide range of industrial applications such as phosphor host compounds [5,6], glazes, pigments [7], electrical insulators [8], and it is an important component in glass ceramics [9].…”