Single Crystalline Films of Ce3+-Doped Y3MgxSiyAl5−x−yO12 Garnets: Crystallization, Optical, and Photocurrent Properties

This research focuses on LPE growth, and the examination of the optical and photovoltaic properties of single crystalline film (SCF) phosphors based on Ce3+-doped Y3MgxSiyAl5−x−yO12 garnets with Mg and Si contents in x = 0–0.345 and y = 0–0.31 ranges. The absorbance, luminescence, scintillation, and photocurrent properties of Y3MgxSiyAl5−x−yO12:Ce SCFs were examined in comparison with Y3Al5O12:Ce (YAG:Ce) counterpart. Especially prepared YAG:Ce SCFs with a low (x, y 1000 °C in a reducing atmosphere (95%N2 + 5%H2). Annealed SCF samples exhibited an LY of around 42% and similar scintillation decay kinetics to those of the YAG:Ce SCF counterpart. The photoluminescence studies of Y3MgxSiyAl5−x−yO12:Ce SCFs provide evidence for Ce3+ multicenter formation and the presence of an energy transfer between various Ce3+ multicenters. The Ce3+ multicenters possessed variable crystal field strengths in the nonequivalent dodecahedral sites of the garnet host due to the substitution of the octahedral positions by Mg2+ and the tetrahedral positions by Si4+. In comparison with YAG:Ce SCF, the Ce3+ luminescence spectra of Y3MgxSiyAl5−x−yO12:Ce SCFs greatly expanded in the red region. Using these beneficial trends of changes in the optical and photocurrent properties of Y3MgxSiyAl5−x−yO12:Ce garnets as a result of Mg2+ and Si4+ alloying, a new generation of SCF converters for white LEDs, photovoltaics, and scintillators could be developed

Single Crystalline Films of Ce3+-Doped Y3MgxSiyAl5−x−yO12 Garnets: Crystallization, Optical, and Photocurrent Properties

This research focuses on LPE growth, and the examination of the optical and photovoltaic properties of single crystalline film (SCF) phosphors based on Ce3+-doped Y3MgxSiyAl5−x−yO12 garnets with Mg and Si contents in x = 0–0.345 and y = 0–0.31 ranges. The absorbance, luminescence, scintillation, and photocurrent properties of Y3MgxSiyAl5−x−yO12:Ce SCFs were examined in comparison with Y3Al5O12:Ce (YAG:Ce) counterpart. Especially prepared YAG:Ce SCFs with a low (x, y < 0.1) concentration of Mg2+ and Mg2+–Si4+ codopants also showed a photocurrent that increased with rising Mg2+ and Si4+ concentrations. Mg2+ excess was systematically present in as-grown Y3MgxSiyAl5−x−yO12:Ce SCFs. The as-grown SCFs of these garnets under the excitation of α–particles had a low light yield (LY) and a fast scintillation response with a decay time in the ns range due to producing the Ce4+ ions as compensators for the Mg2+ excess. The Ce4+ dopant recharged to the Ce3+ state after SCF annealing at T > 1000 °C in a reducing atmosphere (95%N2 + 5%H2). Annealed SCF samples exhibited an LY of around 42% and similar scintillation decay kinetics to those of the YAG:Ce SCF counterpart. The photoluminescence studies of Y3MgxSiyAl5−x−yO12:Ce SCFs provide evidence for Ce3+ multicenter formation and the presence of an energy transfer between various Ce3+ multicenters. The Ce3+ multicenters possessed variable crystal field strengths in the nonequivalent dodecahedral sites of the garnet host due to the substitution of the octahedral positions by Mg2+ and the tetrahedral positions by Si4+. In comparison with YAG:Ce SCF, the Ce3+ luminescence spectra of Y3MgxSiyAl5−x−yO12:Ce SCFs greatly expanded in the red region. Using these beneficial trends of changes in the optical and photocurrent properties of Y3MgxSiyAl5−x−yO12:Ce garnets as a result of Mg2+ and Si4+ alloying, a new generation of SCF converters for white LEDs, photovoltaics, and scintillators could be developed

Development of Tb_1.5Gd_1.5Al₅O₁₂:Ce Single-Crystalline Film Converters for WLED Using a Liquid Phase Epitaxy Growth Method

The investigation of the structural, luminescent and photoconversion properties (color coordinates, correlated color temperature, color rendering index and luminous efficacy) of the single-crystalline films of Ce3+-doped Tb1.5Gd1.5Al5O12:Ce mixed garnet with variable film thickness was performed in this work. These film converters were grown on undoped Y3Al5O12 substrates using the liquid phase epitaxy technique. When combined directly with blue LEDs that were commercially available in the market, the developed garnet film converters were responsible for producing white light. The trend line on the color coordinate diagram was obtained for the first time for the Tb1.5Gd1.5Al5O12:Ce converters with the systematic variation in film thickness in the range of 45–82 µm. Under 464 nm blue LED excitation, the investigated converters with a thickness of 55 µm resulted in an ideal white color

Development of scintillating screens based on the single crystalline films of Ce doped (Gd,Y)3(Al,Ga,Sc)5O12(Gd,Y)_3(Al,Ga,Sc)_5O_{12} multi-component garnets

The paper is dedicated to development of scintillators based on single crystalline films of Ce doped (Gd,Y)3(Al,Ga,Sc)5O12 multi-component garnets onto Gd3Ga5O12 substrates using the liquid phase epitaxy method

Growth and luminescent properties of Ce and Ce–Tb doped (Y,Lu,Gd)2SiO5:Ce(Y,Lu,Gd)_2SiO_5:Ce single crystalline films

The paper presents the results of systematic research directed on the development of scintillating screens based on single crystalline films of Ce and Ce–Tb doped (Y,Lu,Gd)2SiO5 orthosilicates using the liquid phase epitaxy method

Development of the Composite Thermoluminescent Detectors Based on the Single Crystalline Films and Crystals of Perovskite Compounds

This work is dedicated to the development of new types of composite thermoluminescent detectors based on the single crystalline films of Ce-doped GdAlO3 perovskite and Mn-doped YAlO3 and (Lu0.8Y0.2)AlO3:Mn perovskites as well as Ce and Pr-doped YAlO3 single crystal substrates. These detectors were obtained using the Liquid Phase Epitaxy growth method from the melt solution based on the PbO-B2O3 fluxes. Such composite detectors can by applied for the simultaneous registration of different components of mixed ionization fluxes using the differences between the thermoluminescent glow curves, recorded from the film and crystal parts of epitaxial structures. For creation of the new composite detectors, we considered using, for the film and crystal components of epitaxial structures (i) the different perovskite matrixes doped with the same type of activator or (ii) the same perovskite host with various types of activators. The thermoluminescent properties of the different types of epitaxial structures based on the abovementioned films and crystal substrates were examined in the conditions of β-particles and X-ray excitation with aim of determination of the optimal combination of perovskites for composite detectors. It was shown that, among the structures with all the studied compositions, the best properties for the simultaneous thermoluminescent detection of α- and X-rays were the GdAlO3:Ce film/YAlO3:Ce crystal epitaxial structure

Application of the LPE-Grown LuAG: Ce Film/YAG Crystal Composite Thermoluminescence Detector for Distinguishing the Components of the Mixed Radiation Field

Single-crystalline films (SCFs) of the LuAG: Ce garnet grown using the liquid-phase epitaxy method onto YAG single-crystal (SC) substrates were investigated for possible applications as composite thermoluminescent (TL) detectors. Such detectors may help to register the different components of ionizing radiation fields with various penetration depths, e.g., heavy charged particles and gamma or beta rays. It was found that the TL signal of LuAG: Ce SCF sufficiently differs from that of the YAG substrate concerning both the temperature and wavelength of emissions. Furthermore, even by analyzing TL glow curves, it was possible to distinguish the difference between weakly and deeply penetrating types of radiation. Within a test involving the exposure of detectors with the mixed alpha/beta radiations, the doses of both components were determined with an accuracy of a few percent