The thermally connected traps model applied to the thermoluminescence of Eu2+ doped Ba13−xAl22−2xSi10+2xO66 materials (x∼0.6)

Abstract

The thermoluminescence (TL) properties of the Eu 2+ doped Ba 13-x Al 22-2x Si 10+2x O 66 (x0.6) phosphorescent materials (hereafter labeled BASO:Eu) are analyzed on the basis of the thermally connected traps (TCT) model. Basically, in these materials, Eu 2+ cations are photo-ionized under UV excitation, and electrons are trapped at defects. The return to the ground state is thermo-stimulated, and the freed electrons recombine at photo-oxidized activator sites with emission of light. TL properties between 80 and 650 K, as well as an isothermal emission decay (IED) at room temperature, were collected for BASO:Eu1% and BASO:Eu0.5% samples to characterize the phosphorescence mechanism in this series of materials and to determine the trap depths. Thermoluminescence glow curves of BASO:Eu excited either at 254 nm or at 365 nm, or excited at 254 nm for durations of 10 s and 240 s, as well as the IED, agree well with a TCT model. Based on our analysis, phosphorescence in BASO:Eu compounds is associated with the depletion of five traps with depths of 0.56, 0.61, 0.65, 0.69 and 0.73 eV.

Light Delivery, Acoustic Read‐Out, and Optical Thermometry Using Ultrasound‐Induced Mechanoluminescence and the Near‐Infrared Persistent Luminescence of CaZnOS:Nd3+

“…However, TL observations do not distinguish between different types of traps such as might be responsible for either pPL or ML. [ 44 ] In the following, we, therefore, analyze the isothermal decay kinetics of USML and pPL in order to obtain separate insight at the underlying trap levels.…”

Thermoluminescence as a Research Tool to Investigate Luminescence Mechanisms

“…It shows that they act as suitable electron traps like co-dopants of trivalent lanthanides ions in YPO 4 :Ce 3+ ,Ln 3+ . Again, TL is shown to be a sensitive technique to determine energy levels in the band gap and is therefore widely used in the study of persistent luminescence phosphors, as illustrated by the many publications in this field [28,29,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96]. …”

Nonradiative centers in Ba3Si6O12N2:Eu2+ phosphors observed by the below-gap excitation method

“…Recent years, as a candidate of green phosphors to be used in the white light-emitting diodes, one promising oxynitride phosphor material, Ba 3 Si 6 O 12 N 2 :Eu 2þ (BSON), has been studied by many researchers [1][2][3][4][5][6]. They reported the crystal structure [2,4], the intense green PL with good color rendering index [1], the high internal quantum efficiency (IQE) [4] and good thermal stability [2] and so on.…”