•The evidences of multisite structure of Ce3+ dopant in LuAG scintillation material.•The evidences of the lattice expansion of LuAG under influence of RE antisites.•Estimated concentration of ...antisite defects equals to 1.2% of the Al3+ sites.
Low temperature, infrared transmission spectra of lutetium aluminum garnet (LuAG) bulk crystals and epitaxial layers doped with Ce are presented. In the region of intra-configurational 4f–4f transitions the spectra of the bulk LuAG crystal exhibit the signatures of several different Ce3+ related centers. Apart from the dominant center, associated with Ce substituting lutetium, at least six other centers are found, some of them attributed to so-called antisite locations of rare-earth ions in the garnet host, i.e., ions in the Al positions. X-ray diffraction data prove lattice expansion of bulk LuAG crystals due presence of rare-earth antisites.
The paper is dedicated to development of UV emitting scintillating screens for microimaging applications based on the single crystalline films (SCFs) of Ce doped Gd1−xLuxAlO3 and Pr1−xLuxAlO3 (x=0–1) ...multicomponent perovskites grown onto YAlO3 (YAP) substrates using the liquid phase epitaxy (LPE) method with the objective to improve the X-ray stopping power. Recently Riva et al. 1 have reported that the full set of GdxLu1−xAlO3 SCFs with x values in x=0−1.0 range can be crystallized on YAP substrates using this technique. We report here that PrxLu1−xAlO3 SCFs with x values in x=0–0.5 range can be grown also by the LPE method from PbO-B2O3 flux onto the same YAP substrates. The structural quality of the films was studied using X-ray diffraction. The optical properties of Ce3+ doped of Gd1−xLuxAlO3 and Pr1−xLuxAlO3 (x=0−1) multicomponent perovskite films, studied by traditional spectroscopic methods, such as absorption, cathodoluminescence, photoluminescence and light yield measurements under α–particles excitation, are also reported in this work. We have shown that Pb2+ flux related impurity has significantly larger influence on the light yield of Pr0.5Lu0.5AlO3:Ce, GdAlO3:Ce and Gd0.5Lu0.5AlO3:Ce SCFs in comparison with the YAP:Ce and LuAlO3:Ce counterparts grown onto YAP substrates.
•First time LPE growth of Gd1−xLuxAlO3:Ce and Pr1−xLuxAlO3:Ce single crystalline films at x=0–1.•Limitation conditions of LPE growth of perovskite films onto YAlO3 substrates were determined.•Relation between compositions engineering and luminescent properties of films were studied.•Gd3+–Ce3+ and Pr3+–Ce3+ energy transfer in perovskite films under study were investigated.•Large influence of Pb2+ flux related dopant on the light yield of perovskite films was found.
The paper is dedicated to development of scintillators based on the single crystalline films of Ce3+ doped Lu2SiO5 (LSO:Ce) and Y2SiO5 (YSO:Ce) orthosilicates grown by Liquid Phase Epitaxy method ...onto YSO substrates from melt-solutions based on the PbO–B2O3 flux. We also compare the luminescent and scintillation properties of Ce doped LSO:Ce and YSO:Ce single crystalline films with those of their single crystal counterparts, grown by the Czochralski method.
•Growth of (Lu,Y)2SiO5:Ce films by LPE method from PbO based flux onto YSO substrates.•Peculiarities of the luminescent properties of (Lu,Y)2SiO5:Ce films and crystals.•Strong influence of lead related centers on the light yield of (Lu,Y)2SiO5:Ce films scintillators.
This work is dedicated to study the synthesis processes and luminescence properties of micro-crystalline powder phosphors of Ce3+ and Mn2+ doped Ca2YMgScSi3O12 garnets (CYMSSG:Ce and CYMSSG:Ce,Mn) ...The photoluminescence emission spectra and decay kinetics confirm the formation of Ce3+ multicenters in the CYMSSG:Ce powder phosphor due to local inhomogeneity of the different dodecahedral positions and presence of the energy transfer between high-energy and low energy Ce3+ emission centers in this garnet. The effective Ce3+ to Mn2+ energy transfer process is observed in CYMSSG:Ce, Mn phosphors resulting in the redshift of the emission spectra in comparison with CYMSSG:Ce counterpart. We have shown that CYMSSG:Ce and CYMSSG:Ce, Mn powder phosphors can be used as an efficient photoconverter (PC) for creation of the high-power white LEDs (WLEDs). The prototypes of PC-WLEDs, based on 450 nm emitting blue LED and planar layers of CYMSSG:Ce and CYMSSG:Ce, Mn microcrystalline powder phosphors, embedded in the epoxy resin, were prepared and their photoconversion properties were investigated as well.
•Creation of micro-powders Ca2YMgScSi3O12:Ce, Ca2YMgScSi3O12:Ce, Mn and Ca2YMgScSi3O12:Mn using solid-state synthesis.•It is found that Mn2+ ions may either substitute for Ca2+ cations of CYMSSG host and generate the yellow emission band peaked 565 nm and/or substitute for Sc3+ cations to generate the red emission band peaked at 676 nm.•The effective Ce3+ to Mn2+ energy transfer process is observed in CYMSSG:Ce, Mn MP samples resulting in the redshift of the emission spectra to 590 nm in comparison with CYMSSG:Ce counterpart.•Prototype of WLED based on Ca2YMgScSi3O12:Ce, Ca2YMgScSi3O12:Mn, Ce phosphors and blue-chip is created.
•High-performance Al2O3:Ce single crystalline films were grown by LPE method.•Basic parameters of the Ce3+ luminescence in Al2O3 host were determined.•Al2O3:Ce film samples show relatively large ...scintillation light yield.
The paper is dedicated to study the luminescent and scintillation properties of the Al2O3:Ce single crystalline films (SCF) grown by LPE method onto saphire substrates from PbO based flux. The structural quality of SCF samples was investigated by XRD method. For characterization of luminescent properties of Al2O3:Ce SCFs the cathodoluminescence spectra, scintillation light yield (LY) and decay kinetics under excitation by α-particles of Pu239 source were used. We have found that the scintillation LY of Al2O3:Ce SCF samples is relatively large and can reach up to 50% of the value realized in the reference YAG:Ce SCF. Using the synchrotron radiation excitation in the 3.7–25eV range at 10K we have also determined the basic parameters of the Ce3+ luminescence in Al2O3 host.
The work deals with the growth and investigation of luminescent properties of scintillators based on the single crystalline films (SCF) of the Ce3+ doped Lu3−xGdxAl5−yGayO12 multicomponent garnets ...prepared by the Liquid Phase Epitaxy (LPE) method. We show that full set of Lu3−xGdxAl5−yGayO12 SCFs with x values in the 1.25–1.5 range and y values ranging from 0 to 4.0 in melt solution (MS) can be successfully crystallized by the LPE method onto Y3Al5O12 substrates from the MS based on PbO–B2O3 flux. The absorption, X-ray excited luminescence, photo-luminescence, thermoluminescence and also the light yield measurements under excitation by α-particles of Pu239 and Am241 radioisotopes were further employed for the characterization of the Lu3−x GdxAl5−yGayO12 SCF. We show that among all the investigated Lu3−xGdxAl5−yGayO12:Ce SCF scintillators, the best LY is realized in the Lu1.5Gd1.5Al1.5Ga3.5O12:Ce sample composition in MS.
•Growth of Lu3−xGdxAl5−yGayO12:Ce film with x=1.25–1.5 and y=0–4.0 onto YAG substrates.•Lattice constant of films and film-substrate misfit non-monotonically depends on Ga content.•Optical properties of films depend on Ga content in the octahedral and tetrahedral sites of garnet host.•Lu1.5Gd1.5Al3.5-4.0Ga3.5-4.O12:Ce films show very low thermoluminescence above RT range.•Best LY under α–particles excitation possess Lu1.5Gd1.5Al1.5Ga3.5O12:Ce films.
► Comparison of the luminescence and scintillation properties of YAG:Ce crystals, films and transparent ceramic. ► Antisite defects and oxygen vacancies as emission centers in YAG host. ► Influence ...of the boundaries of grains on luminescent properties of YAG:Ce ceramic.
In this work, we have performed the comparative analysis of the luminescent and scintillation properties of Y3Al5O12:Ce (YAG:Ce) single crystals (SC), single crystalline films (SCF) and transparent optical ceramics (OС) using the traditional spectral methods as well as the luminescence spectroscopy under excitation by pulsed synchrotron radiation in the fundamental absorption range of YAG host. We have shown that the properties of YAG:Ce OC are rather closer to the properties of SCF counterpart where YAl antisite defects are completely absent than to the properties of SC of this garnet with large concentration of YAl antisite defects. At the same time, the luminescence spectra of YAG:Ce OC and SC show the emission bands in the 200–450nm range related to YAl antisite defects and charged oxygen vacancies (F+ and F-centers). YAG:Ce ОС also possesses significantly higher thermoluminescence in the range above room temperature and large contribution of slow components in the Ce3+ luminescence decay under high-energy excitation in comparison with SC and SCF of this garnet. The mentioned properties of YAG:Ce OC are caused by the participation of antisite defects and charged oxygen vacancies located in OC mainly on the boundaries of grains, as trapping centers in the energy transfer processes from the host to the Ce3+ ions.
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