Scintillation and Energy-Storage Properties of Micro-Pulling-Down Grown Crystals of Sc3+- and La3+-Doped YAlO3 Perovskite

Abstract

The scintillation and energy-storage properties of YAlO3 (YAP) crystals doped with Sc3+ and La3+ isoelectronic dopants were investigated in this work. The YAP:Sc and YAP:La crystals were grown from the melt with a nominal Sc and La content in the 0.2–5.0 mol.% range using the novel micro-pulling-down method. We found that the segregation coefficient of Sc ions in YAP:Sc (0.2–1.0 mol.%) crystals is about of 0.35–0.4 and decreases to around 0.2 at Sc content of 5.0 mol.% when the segregation coefficient of La ions in YAP:La (1.0–5.0 mol.%) crystals is 0.008–0.01. The scintillation and stimulated luminescence phenomena, like thermo- and photoluminescence, were utilized for the property characterization of the studied materials. The cathodoluminescence and X-ray-excited luminescence were used for the imitation of scintillation in the YAP:Sc and YAP:La crystals. The influence of Sc3+ and La3+ dopant concentration on the CL and RL emission spectra, as well as the shape of the measured thermoluminescence (TL) glow-curves, was also investigated. The measured emission spectra showed dominant emission of Sc3+ and La3+ ions in the UV range. For this reason, the YAP:Sc and YAP:La crystals can be considered for creation of ultraviolet (UV)-emitting scintillators. For the undoped YAlO3 crystals, the main TL emission peak occurs in a low-temperature range at 375 K. Meanwhile, even a small addition of dopants causes a strong suppression of luminescence of the YAP host and high-temperature peaks become dominant in the TL glow-curves of YAP:Sc and YAP:La crystals. Moreover, the amplitude of emission does not change monotonically with increasing dopant content. The kinetic parameters of emission were also evaluated, and the first-order behavior was confirmed in all cases. The dosimetric properties of investigated materials such as dose response, fading rate, and the lowest measurable dose are also discussed. The obtained results tend to suggest that the YAlO3 perovskite host, apart from its application for the development of efficient scintillators, may also be considered as a promising matrix for the creation of energy-storage phosphors for dosimetric applications.

Electron Paramagnetic Resonance and Optical Studies of Thermoluminescence Processes in Mn-Doped YAlO3 Single Crystals

“…The model presented in Figure 11 foresees the existence of a few types of electron and hole traps intrinsic to the YAlO 3 lattice, which are responsible for the TL peaks observed at temperatures up to 500 K. It should be mentioned that the TL peaks, the position and depth of which correspond to traps I− II, were also observed as the main ones in YAP and (Lu−Y)AP crystals doped with Ce 3+ ions, 38,39 while traps I−III were detected on the host emission in nominally undoped YAP. 40 This supports the suggestion that these traps are intrinsic to the YAlO 3 lattice and not related to impurity ions. Trap III, with an activation energy of 1.7 eV, is the deepest intrinsic trap which becomes dominant in the YAlO 3 crystals grown from Yrich composition.…”

First Principles Calculations of Atomic and Electronic Structure of TiAl3+- and TiAl2+-Doped YAlO3

“…A few examples that emphasize the diversity of applications of the doped YAP host are as follows: (i) scintillating applications (especially when doped with the La 3+ , Ce 3+ , Pr 3+ ions) [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ]; (ii) thermoluminescent material (YAP with Mn ions) [ 29 , 30 , 31 , 32 , 33 , 34 ]; (iii) solid-state laser applications [ 35 , 36 ] and (iv) electroluminescent devices [ 37 ]. Various aspects of the doped YAP crystal were studied theoretically, such as crystal field splittings of the Mn 3+ and Mn 4+ energy levels [ 38 ], splittings of the Ce 3+ 4 f and 5 d states [ 39 ] and Ce 3+ 4 f ground state position in the YAP band gap [ 40 , 41 ].…”

Band Gap Engineering and Trap Depths of Intrinsic Point Defects in RAlO3 (R = Y, La, Gd, Yb, Lu) Perovskites

“…As follows from the analysis of the TSL data presented above or available literature data, 50,52,78,79 the defects, which form the main high-temperature TSL peaks in YAlO 3 and YAlO 3 :Mn 4+ , usually have depths from 1.20 to 1.43 eV. It is commonly assumed that these defects are electron traps.…”

“…As follows from the analysis of the TSL data presented above or available literature data, ,,, the defects, which form the main high-temperature TSL peaks in YAlO 3 and YAlO 3 :Mn 4+ , usually have depths from 1.20 to 1.43 eV. It is commonly assumed that these defects are electron traps. ,− , According to Table S5, none of the single point defects like Y Al , V O , O i , or V Y have energy levels of appropriate depth with respect to the CB to be responsible for the high-temperature TSL or the radiation-induced coloration of YAlO 3 crystals stable at room temperature.…”