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Sm-doped CaCl 2 , SrCl 2 , and BaCl 2 bulk crystals were synthesized using the conventional vertical Bridgman method, and the photoluminescence, radioluminescence, and detector properties were evaluated. The Sm-doped CaCl 2 , SrCl 2 , and BaCl 2 samples show a broad emission band at 750, 690, and 650 nm, respectively, which is attributable to the 5d-4f transitions of Sm2+. The pulse height spectra under 137Cs γ-rays (662 keV) show that the Sm-doped CaCl 2 and SrCl 2 exhibit 9300 and 33000 photons/MeV, respectively. These samples can be used for γ-ray measurements in the red to NIR region. • Sm-doped CaCl 2 , SrCl 2 , and BaCl 2 crystals were synthesized using the conventional vertical Bridgman method. • The photoluminescence, radioluminescence, and detector properties were evaluated. • The samples show a broad emission band at 600–800 nm due to Sm2+. • Sm-doped CaCl 2 , SrCl 2 , and BaCl 2 exhibit light yield of 9300, 33000, and 16000 photons/MeV, respectively. [ABSTRACT FROM AUTHOR]

Single crystals of Gd 3 (Ga,Al) 5 O 12 :Ce,Mg with different concentration of Mg2+ ions varying from 0 to 0.029 at.% are investigated by the X-ray diffraction, steady-state and time-resolved photoluminescence, and thermally stimulated luminescence (TSL) methods in a wide temperature range (77–510 K). The origin and structure of the luminescence centers are considered. The influence of Mg2+ ions on the structure of the Ce3+-related excited state, the processes taking place in this state, and the TSL characteristics is clarified. At low temperatures, the photoluminescence optical quenching in close {Ce3+ - Mg2+} pairs is found to be responsible for the light yield reduction accompanied with the acceleration of the luminescence decay kinetics. At room temperature, the luminescence quenching can be additionally caused by the thermal ionization of the 5d 1 excited state of Ce3+ ion, whose probability increases with the increasing Ga content. The conclusion is made that in order to create the fast scintillator with the maximum light yield, the concentration of intrinsic crystal lattice defects in Gd 3 (Ga,Al) 5 O 12 :Ce,Mg should be minimized, the optimum composition of the host should be chosen, and the balance between the concentrations of the doped Mg2+ and Ce3+ ions should be optimised. • Photo- and thermoluminescence and XRD of Gd 3 (Ga,Al) 5 O 12 :Ce,Mg crystals are studied. • Influence of Mg2+ ions on the Ce3+-related luminescence and excited states is clarified. • Optical quenching in close {Ce3+ - Mg2+} pairs results in the light yield reduction and accompanied with acceleration of the Ce3+ luminescence decay kinetics. • Ga3+ ions and intrinsic defects strongly influence the luminescence thermal quenching. • Optimum host composition and preferable Ce3+/Mg2+ concentration ratio are considered. [ABSTRACT FROM AUTHOR]

Strontium phosphate (SrO–P 2 O 5 –Al 2 O 3 –Gd 2 O 3) glasses with 0.05, 0.1, 0.5, and 1 mol % CeO 2 were prepared by the conventional melt quenching technique. These glasses' luminescence, scintillation, and physical properties were measured and discussed in detail. The density, refractive index, and oxygen packing density of the studied glasses were increased with an increase in CeO 2 concentration. At lower concentrations of CeO 2 , the characteristic 310 nm emission from Gd3+ and broadband emission from Ce3+ ions were obtained under X-ray excitations. The intensity of both Gd3+ and Ce3+ emission bands under 270 nm Gd3+ excitations reduced with further increase in CeO 2 , showing the delayed energy transfer from Gd3+ to Ce3+ ions. The integrated X-ray-induced luminescence intensity of 0.5% CeO 2 glass was found to be 21% that of reference BGO crystal. For the lower concentration of CeO 2 , a slow decay time along with the fast Ce3+ decay was observed and disappears for higher CeO 2 concentrations. The fast luminescence decay in the range of 22 ns–30 ns was observed for all the PSAG:Ce glasses, which was attributed to the lifetime of the 4f-5d transition of the Ce3+ ions. The faster decay time and reasonable scintillation light suggest the application of these glasses for radiation detector applications. • Strontium phosphate glasses with various concentrations of CeO 2 are fabricated. • The density, refractive index, and OPD increased with CeO 2 concentrations. • Efficient energy transfer from Gd3+ to Ce3+ was confirmed from luminescence. • X-ray-induced scintillation light was found to be 21% that of BGO crystal. [ABSTRACT FROM AUTHOR]

0.5, 1, 2, and 5% Er-doped La 3 Ga 5 SiO 14 (LGS) single crystals were synthesized by the Floating Zone method and the photoluminescence (PL) and scintillation properties were characterized. Emission peaks appeared at visible–near-infrared (NIR) regions. Their spectral features matched with those due to the 4f–4f transitions of Er3+. The PL quantum yields of 0.5, 1, 2, and 5% Er-doped samples were respectively 45.0, 73.3, 82.5, and 69.4%. The decay times due to the 2H 9/2 –4I 15/2 transitions of Er3+ were obtained when visible ranges were monitored under excitation of both visible lights and X-rays. All the prepared samples showed good linearity between the X-ray exposure dose rate and scintillation signals in NIR ranges. The best lower detection limit in prepared samples was 5 mGy/h recorded by the 2% Er-doped LGS. • Er-doped La 3 Ga 5 SiO 14 single crystals were synthesized by the Floating zone method. • Luminescence due to 4f–4f transitions of Er3+ was observed in both visible and near-infrared regions. • Quantum yields of 0.5, 1, 2, and 5% Er-doped samples were respectively 45.0, 73.7, 82.5, and 69.4%. • The best lower detection limit in prepared samples was 5 mGy/h obtained by 2% Er-doped sample. [ABSTRACT FROM AUTHOR]

Ce differently (0, 0.01, 0.1, 1, 2 and 5% with respect to Mg) doped LiMgAlF 6 ceramics were synthesized by the spark plasma sintering (SPS) method. In photoluminescence (PL), emission bands appeared at 300 nm with 30 ns day time, and these emission properties were almost the same in scintillation under X-ray irradiation. Further, thermally stimulated luminescence (TSL) was observed after X-ray irradiation, and the primary glow peak temperature was 160 °C with a lower detection limit of ∼10 mGy. • Ce-doped LiMgAlF 6 ceramics were prepared by the spark plasma sintering method. • Photoluminesence and scintillation properties were investigated. • Thermally stimulated luminescence properties were evaluated. [ABSTRACT FROM AUTHOR]

The photoluminescence and scintillation properties of n-bromophenethylammonium lead chloride ((n-BrPEA) 2 PbCl 4) (n = 4, 3, and 2) and phenethylammonium lead chloride ((PEA) 2 PbCl 4) have been investigated. All the samples showed broad emission peaks at 400–700 nm upon excitation by UV light or X-ray. The decay time constants of 8–28 ns were obtained which originated from the recombination of self-trapped exciton (STE) within inorganic layers. The afterglow levels at 20 ms after 2 ms of X-ray irradiation of (4-BrPEA) 2 PbCl 4 and (3-BrPEA) 2 PbCl 4 (76 and 55 ppm) were better than (PEA) 2 PbCl 4 (379 ppm). The light yield of (4-BrPEA) 2 PbCl 4 (3100 photons/5.5 MeV-α) was higher than (PEA) 2 PbCl 4 (1400 photons/5.5 MeV-α). • (BrC 6 H 4 C 2 H 4 NH 3) 2 PbCl 4 crystals were grown by the slow cooling method. • All the crystals showed the luminescence due to the recombination of the self-trapped excitons confined in inorganic layers. • The (4-BrC 6 H 4 C 2 H 4 NH 3) 2 PbCl 4 crystal showed the highest QY in the present crystals. • The light yields of the (4-BrC 6 H 4 C 2 H 4 NH 3) 2 PbCl 4 crystals surpassed that of the unsubstituted crystal. [ABSTRACT FROM AUTHOR]

Ce,Mg:Lu 2 YGa x Al 5-x O 12 (x = 1.5, 2, 2.5, 3) ceramic scintillators were fabricated by oxygen sintering combined with air annealing using nano-powders synthesized by the co-precipitation method. The Ce3+ 5d 1 → 4f (2F 5/2 , 2F 7/2) luminescence band was blue shifted with increasing Ga content due to the decrease in the crystal field splitting of the 5d levels. At room temperature (RT), the decrease of photoluminescence decay time and scintillation decay time was observed with increasing Ga content. At 662 keV γ-rays, the sample Ga2 exhibited high light yield (LY) of 28,700 photons/MeV, fast scintillation decay times of 17.7 ns (17 %) + 45.7 ns (83 %), and good time resolution of ∼220 ps. At RT, the decrease of LY value for the samples Ga2.5 and Ga3 could be attributed to the larger thermal ionization of the excited Ce3+ centers. • Scintillation properties of Ce,Mg:Lu 2 YGa x Al 5-x O 12 (x = 1.5, 2, 2.5, 3) ceramics are investigated. • All ceramic samples show fast effective scintillation decay time less than 47 ns. • Sample x = 2 shows high LY of ∼28,700 ph/MeV @662 keV γ rays. • Samples x = 2 and 2.5 show good coincidence time resolution of 220 ps. [ABSTRACT FROM AUTHOR]

• CuI thin films have been synthesized in iodine solution at room temperature. • An apparent NBE peak can be recognized both in PL and XEL spectra. • Iodine-rich condition is beneficial to improve the XEL yield of CuI thin films. CuI is considered as a potential candidate for fast scintillator material due to the fast decay time. However, the ever-reported CuI scintillator usually demonstrates a more intensive deep-level emission with the decay time as long as 2.82 μs, which is unfavorable for the application as a fast scintillator material. In present work, γ-phase CuI were synthesized by iodizing Cu thin films in iodine solution at room temperature. An apparent near band-edge emission (NBE) is observed both in photoluminescence and X-ray excited luminescence spectra. By analyzing the variation of the relative intensity ratio of the sub-peaks composing NBE against different fabrication conditions, it can be deduced that Cu vacancy and surface chemisorbed iodine are responsible for the above luminescence behavior. It is hoped that these findings may boost the exploration of CuI thin films as fast scintillator materials. [ABSTRACT FROM AUTHOR]

(n-ClC 6 H 4 C 2 H 4 NH 3) 2 PbCl 4 ((n-ClPEA) 2 PbCl 4) (n = 2, 3, and 4) and (n-C 6 H 5 C 2 H 4 NH 3) 2 PbCl 4 ((PEA) 2 PbCl 4) crystals were synthesized by the slow-cooling method, and the photoluminescence (PL) and scintillation properties were evaluated. All the samples showed self-trapped excitons luminescence at 400–700 nm. The PL quantum yields of the (n-ClPEA) 2 PbCl 4 (n = 2, 3, and 4) and (PEA) 2 PbCl 4 crystals were 2.2, 0.9, 11.2, and 2.2 %, respectively. In the pulse-height spectra of 241Am α-rays (5.5 MeV), full energy absorption peaks were observed, and the light yields of (n-ClPEA) 2 PbCl 4 (n = 2, 3, and 4) and (PEA) 2 PbCl 4 crystals were respectively calculated to be 530, 490, 2,800, and 1,400 photons/5.5 MeV-α with typical errors of ± 10 %. [ABSTRACT FROM AUTHOR]

0.05, 0.1, 0.5, and 1.0 % Dy-doped YVO 4 single crystals were prepared by the optical floating zone technique to obtain photoluminescence (PL) and scintillation properties. All the samples showed the emission owing to charge transfer from V5+ ions to O2− ions inside [VO 4 ]3- and the 4f–4f transitions of Dy3+ ions. Light yields exhibited 37,000 (0.05 % Dy), 42,000 (0.1 % Dy), 44,000 (0.5 % Dy), and 39,000 photons/MeV (1.0 % Dy), based on the pulse height spectra. In afterglow properties, afterglow levels were 37.7 (0.05 % Dy), 25.7 (0.1 % Dy), 23.2 (0.5 % Dy), and 20.6 (1.0 % Dy) ppm. • We have synthesized Dy-doped YVO 4 single crystals by floating zone method. • We have characterized the photoluminescence, and scintillation properties of the Dy-doped YVO 4 single crystal. • Pulse height spectra revealed that the light yield of 0.05, 0.1, 0.5, and 1.0 % Dy-doped YVO 4 single crystals was 37,000, 42,000, 44,000, and 39,000 photons/MeV, respectively. • In afterglow properties, afterglow levels were 37.7 (0.05 % Dy), 25.7 (0.1 % Dy), 23.2 (0.5 % Dy), and 20.6 (1.0 % Dy) ppm. [ABSTRACT FROM AUTHOR]

We fabricated BaCaBO 3 F (BCBF) with various Dy concentrations (0.1 %, 1 %, and 5 %), and evaluated the luminescence properties for radiation dosimetry. Sharp scintillation peaks originating from the 4f → 4f transition of Dy3+ were observed. Furthermore, thermally stimulated luminescence (TSL) glow curves were recorded, and a TSL glow peak at approximately 120 °C was observed. The 0.1 % Dy-doped BCBF exhibited the highest TSL intensity, and dose response curves of the 0.1–1 % Dy-doped BCBF were obtained in the 0.1–10000 mGy range. Moreover, at least seven activation energy levels related to TSL were confirmed by the TSL isothermal decay analysis. [ABSTRACT FROM AUTHOR]

Optical and scintillation properties of 50 AE O-50SiO 2 -1SnO (AE = Mg, Ca, Sr, Ba) glasses were investigated. In photoluminescence (PL) and scintillation, the glasses showed a luminescence peak around 400 nm which was attributed to the T 1 -S 0 transitions of Sn2+. The afterglow levels of the AE = Mg and Ba glasses were better than that of a commercial Tl-doped CsI scintillator. The light yields of the glasses were quantitatively acquired and the AE = Ba glass showed the highest light yield of 63 ph/5.5 MeV-α of among the glasses. [ABSTRACT FROM AUTHOR]

(C 6 H 5 C 2 H 4 NH 3) 2 Pb 1- x Ca x Br 4 (x = 0.05, 0.1, and 0.25) crystals were grown by the solvent diffusion method and evaluated for the photoluminescence and scintillation properties. When irradiated by X-rays, emission peaking at 440 nm due to exciton emission was observed. The pulse height spectra of (C 6 H 5 C 2 H 4 NH 3) 2 Pb 1- x Ca x Br 4 under 137Cs γ-ray irradiation demonstrate that the light yields were 20,000, 17,000, and 16,000 ph/MeV in x = 0.05, 0.1, and 0.25 samples, respectively. Ca-substitution significantly enhances the photoluminescence quantum yield and scintillation light yield. • (C 6 H 5 C 2 H 4 NH 3) 2 (Pb,Ca)Br 4 crystals were evaluated for the photoluminescence and scintillation properties. • (C 6 H 5 C 2 H 4 NH 3) 2 (Pb,Ca)Br 4 crystals exhibit a sharp emission peaking at 440 nm due to exciton luminescence. • Pulse height spectra under 137Cs γ-rays demonstrate the light yields was 20,000 ph/MeV. • Ca-substitution enhances both the photoluminescence and scintillation properties. [ABSTRACT FROM AUTHOR]

Gd3+ and Ce3+ doped and co-doped NaCaYF 6 were synthesized noting the lack of luminescence studies in this material by using hydrothermal method. Synthesized NaCaYF 6 is also known by the mineral name Gagarinite. X-ray diffraction studies of prepared sample performed to confirm the identification of the phase pure fluoride compound. Energy dispersive spectra (EDS) and elemental mapping also recorded to confirm the compositions. Photoluminescence (PL) studies performed for recording PL Excitation (PLE) and PL Emission (PL) Spectra. Characteristic luminescence of Gd3+ ions and Ce3+ ions were observed in NaCaYF 6. The PLE of Ce3+ doped NaCaYF 6 phosphor shows broad excitation band centered at 294 nm with other weak shoulder peak at 272 nm. A typical double humped broad band emission obtained for the 294 nm excitation. Emission peak of 322 nm appears due to Ce3+ (5d–4f) transition with an additional shoulder peak at 315 nm. The PL spectra of the Gd3+-doped NaCaYF 6 excited at 272 nm consists of a dominant UVB emissions at 311 nm due to the transitions 6P 7/2 → 8S 7/2 of Gd3+ ions. No concentration quenching for Ce3+ was observed while luminescence of Gd3+activator got quenched at 1 mol %. The peculiarity of Gd3+ emission was the long lifetime of the order of 10 ms. Luminescence characteristics are explained using the known energy level diagrams for the lanthanide activators. The results revealed that Gd3+ and Ce3+ doped NaCaYF 6 compound could find a promising application for the UV-emitting phototherapy lamps. [Display omitted] • Novel results on observation of UV emission in NaCaYF 6 :Ln3+ (Ln3+ = Ce, Gd) materials are reported for the first time. • The samples of pristine and Ln3+ doped NaCaYF 6 have been prepared by the Hydrothermal method. • Characteristic line emission for Ce and Gd doped NaCaYF 6 are observed. • This can be useful in various UV applications. [ABSTRACT FROM AUTHOR]

Four phenanthroimidazole-functionalized coumarins (C-PI-Bu , C-PI-CN, C-PI-TRZ, and C-PI-Cz) containing a 7-diethylaminocoumarin unit and a phenanthroimidazole (PI) unit with different phenyl substituent at the N 1-position, were successfully synthesized and characterized by NMR (1H and 13C), high-resolution mass spectrometry and elemental analysis. The structure-property relationships of the compounds were revealed by systematically investigating their thermal stability, photophysical and electrochemical properties. All four compounds exhibit bright blue-green emission with high fluorescence quantum yield (75.36 %–97.00 %) in dichloromethane solution and green emission in the solid-state. The organic light-emitting diodes (OLEDs) with a device of ITO/PEDOT:PSS (30 nm)/TBADN:coumarin derivative (x, wt%) (25 nm)/TPBi (35 nm)/Liq (2 nm)/Al (150 nm) were fabricated and characterized. The above OLEDs showed the best EL performances with a maximum brightness (L max) of 8500 cd/m2, a maximum current efficiency (CE max) of 3.45 cd/A, and a maximum external quantum efficiency (EQE max) of 1.30 %. [Display omitted] • Four phenanthroimidazole-functionalized coumarins were synthesized for OLEDs. • The phenanthroimidazole-functionalized coumarins exhibited strong emission in solution and in solid-state. • Devices containing the cyanophenyl substituted compound showed L max of 8500 cd/m2, CE max of 3.45 cd/A, and EQE max of 1.30 %. [ABSTRACT FROM AUTHOR]

Hexagonal-structure Mg 4 Ta 2 O 9 (MTO) powders doped by 0.25 at% RE (RE = La3+, Ce3+, Pr3+, Nd3+, Sm3+, Eu3+, Gd3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3 +, Yb3+, Lu3+, Y3+, Sc3+) were synthesized. All the rare earth-doped samples were checked by X-ray diffraction (XRD) and confirmed to be monophasic powders. Among them, Mg 4 Ta 2 O 9 doped by 0.25 at% Gd3+ and Sc3+ had higher X-ray excited luminescence (XEL) emission peak intensities, 3.05 and 2.79 times of MTO, respectively. The optimal concentrations of Gd3+ and Sc3+ were investigated based on XEL main emission peak intensity changing with the amount of dopants in the range of 0∼1.0 at%. The optimal XEL emission peak intensities were measured 3.32 and 3.09 times of MTO for MTO: 0.8 at% Gd3+ and MTO: 0.4 at% Sc3+, respectively. The photoluminescence (PL) emission peaks at around 370 nm correspond to two excitation peaks at 158 and 215 nm. The excitation peak at 158 nm is about 10 times more than that of at 215 nm in intensity. The emission spectra excited by vacuum ultraviolet light at 158 nm and ultraviolet light at 215 nm were investigated associated with scintillation emission mechanism. MTO: 0.8 at% Gd3+ and MTO: 0.4 at% Sc3+ show potential application in security inspection, industrial detection, etc. • Single-phase Mg 4 Ta 2 O 9 : 0.25 at% RE (RE = La3+, Ce3+, Pr3+, Nd3+, Sm3+, Eu3+, Gd3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3 +, Yb3+, Lu3+, Y3+, Sc3+) samples were synthesized. • Single-phase Mg 4 Ta 2 O 9 : x at% M (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0; M = Gd3+, Sc3+) samples were synthesized. • MTO: 0.8 at% Gd3+ among MTO: x at% Gd3+ and MTO: 0.4 at% Sc3+ among MTO: x at% Sc3+ have the highest excitation peaks at 158 and 215 nm. • MTO: 0.8 at% Gd3+ and MTO: 0.4 at% Sc3+ have highest relative main XEL emission peak intensities of 3.27 and 3.09 times of MTO, respectively. • The scintillation emission mechanism of improving XEL properties of Mg 4 Ta 2 O 9 scintillators by rare-earth doping is thoroughly analyzed. [ABSTRACT FROM AUTHOR]

(K,Rb) 2 CuBr 3 crystals were fabricated by the slow cooling method, and their photoluminescence (PL) and scintillation properties were examined. Emission bands were observed at 350–550 nm under UV and X-ray irradiation. PL quantum yields of K 2 CuBr 3 , (K 0.25 ,Rb 0.75) 2 CuBr 3 , (K 0.5 ,Rb 0.5) 2 CuBr 3 , (K 0.75 ,Rb 0.25) 2 CuBr 3 , and Rb 2 CuBr 3 were respectively 75.8, 71.0, 82.3, 96.9, and 96.3%. The scintillation decay curves were approximated by a sum of three exponential functions, and the decay time constants due to recombination of self-trapped excitons were 58–63 μs. The afterglow levels of the K and Rb-mixed samples at 20 ms passed after X-ray irradiation decreased to 10–40 ppm, compared with those of K 2 CuBr 3 and Rb 2 CuBr 3. Among these samples, (K 0.75 , Rb 0.25) 2 CuBr 3 showed the highest light yield of 7400 ph/MeV among the samples calculated from the pulse height spectra of 137Cs γ-rays (662 keV). • (K,Rb) 2 CuBr 3 crystals were synthesized by the slow cooling method. • The afterglow levels of the (K,Rb) 2 CuBr 3 were 10–40 ppm. • (K 0.75 ,Rb 0.25) 2 CuBr 3 showed the highest light yield (7400 ph/MeV) in prepared samples. [ABSTRACT FROM AUTHOR]

Europium doped borosilicate glasses were prepared in CO reducing atmosphere. The glasses were systematically investigated through XPS, photoluminescence (PL), fluorescence decay curves and X-ray excited luminescence (XEL). XPS results show that the glasses contain Eu2+ and Eu3+ at the same time. Under the excitation of 360 nm light, only a broad blue emission with peak around 440 nm due to the 5d→4f transition of Eu2+ is observed, while the emissions from Eu3+ do not appear in the PL spectra. The fluorescence decay curves were monitored at 440 nm, and the measured lifetimes are in the range of 0.17–0.42 μs. The PL results indicate that the PL emission from Eu2+ is significantly intense than the PL emissions from Eu3+. Upon X-ray excitation, two main emissions with peaks at 445 nm and 616 nm corresponding to Eu2+ and Eu3+ are obtained. The XEL results reveal that the XEL emissions from Eu3+ are comparably intense as the XEL emission from Eu2+. The results indicate that europium doped borosilicate glass could be a potential scintillating material in X-ray detection filed. [ABSTRACT FROM AUTHOR]

BaCl 2 :Eu transparent ceramics were synthesized by the spark plasma sintering method, and concentration dependence of Eu on optical and scintillation properties was investigated. BaCl 2 :Eu transparent ceramics showed photoluminescence (PL) and scintillation peaks at 400 nm due to 5d–4f transition of Eu2+. The PL and scintillation decay time constants of BaCl 2 :Eu transparent ceramics were ∼400 ns. The PL quantum yields (QY s) of 0.05, 0.1, 0.5, and 1% BaCl 2 :Eu transparent ceramics were 28.5, 25.6, 16.2, and 13.9%, respectively. The afterglow levels of BaCl 2 :Eu transparent ceramics were lower than CsI:Tl single crystal in practical use. The scintillation light yield of the 0.5% doped BaCl 2 :Eu transparent ceramic was 9800 photons/MeV when γ-rays by 137Cs were irradiated. • BaCl 2 :Eu transparent ceramics were synthesized using the SPS method. • We investigated the optical and scintillation properties. • The scintillation peak due to 5d–4f transition of Eu2+ was observed at 400 nm. • The 0.5% Eu-doped sample showed the highest LY (9800 ph/MeV) under 137Cs γ-ray irradiation. [ABSTRACT FROM AUTHOR]

To develop glass scintillators, Eu 2 O 3 -doped tellurite glasses (TeO 2 –Nb 2 O 5 –SrO–Eu 2 O 3) (TNbSrEu) were prepared, and their luminescence characteristics were investigated. Several photoluminescence peaks at about 578, 592, 613, 652, and 701 nm were observed when excited by 530 nm excitation light. They originated from 4f→4f transition of Eu3+. Their photoluminescence decay times under 530 nm excitation light were approximately 0.7 ms, which was a typical time of 4f→4f transition of Eu3+. Further, some scintillation peaks originating from 4f→4f transition of Eu3+ were detected at 577, 593, 613, and 652 nm, and scintillation decay times were in the time region of 0.21–0.35 ms. Furthermore, the afterglow levels were from 560 ppm to 317 ppm, showing a decreasing trend in levels with increasing Eu 2 O 3 concentration. • To develop glass scintillators, Eu 2 O 3 -doped tellurite glasses (TeO 2 –Nb 2 O 5 –SrO–Eu 2 O 3) were prepared. • Some scintillation peaks originating from 4f.→4f transition of Eu3+ were detected. • The tellurite glasses showed a decreasing trend in afterglow levels with increasing Eu 2 O 3 concentration. [ABSTRACT FROM AUTHOR]

We synthesized 0, 0.02, 0.2, 1.0, and 10% Ce3+ doped CaF 2 AlF 3 AlPO 4 glasses; and then, we evaluated their photoluminescence (PL), scintillation and thermally stimulated luminescence (TSL) properties. Depending on the concentration of Ce3+, PL quantum yield (QY) ranged from 15.8 to 62.8%. When the materials were irradiated by X-rays, scintillation was observed with an emission peak around 330 nm due to 5d→4f transitions of Ce3+. The scintillation decay times ranged 14–25 ns. The glasses showed intense TSL, and the glow peak was broad peaking around 100 °C. The 0.2% and 1.0% Ce3+ doped samples demonstrated high sensitivity with a good linearity over 5 orders of magnitude (0.1 mGy–10 Gy). • We evaluated Ce-doped CaF 2 AlF 3 AlPO 4 glasses PL, Scintillation and TL properties. • 0.2% Ce-doped samples had the highest QY. • By measuring scintillation properties, all Ce-doped samples emitted around 320 nm. • We measured dose response of each sample. [ABSTRACT FROM AUTHOR]

Abstract In this study, the Gd3+-substituted yttrium aluminum perovskite epitaxial films activated by Ce3+ ions, (YGd)AlO 3 :Ce3+ with Gd content 0–44%, were prepared by liquid phase epitaxy technique and their optical, luminescence, and scintillation properties were studied. The results showed that films with Gd content below 20% had greater photoluminescence and radioluminescence intensities. For higher Gd concentrations, the Ce3+ emission gradually decreased and the Ce3+ decays were accelerated. The model of bidirectional non-radiative energy transfer between Gd3+ and Ce3+ ions and energy migration over the Gd3+ sublattice is suggested and the processes responsible for the observed effects are discussed. Highlights • (GdY)AlO 3 :Ce3+ perovskite scintillators were characterized. • Bidirectional Gd3+-Ce3+ energy transfer in GdYAP:Ce perovskite was proposed. • Gd co-doped YAlO 3 :Ce3+,Gd3+ perovskite films were prepared by liquid phase epitaxy. [ABSTRACT FROM AUTHOR]

Abstract Eu3+ doped tellurite scintillating glasses were prepared by the conventional melt-quenching method. The physical and luminescent properties of glasses were investigated by DTA, density, transmittance spectra, photoluminescence spectra, and X-ray excited luminescence (XEL) spectra. The densities of the glasses are in the range from 5.89 g/cm3 to 6.05 g/cm3. The glasses exhibit intense red emissions upon 393 nm light and X-ray excitations. The maximum integral XEL intensity of the glasses is about 6% of that of commercial Bi 4 Ge 3 O 12 (BGO) scintillating crystal. The results reveal that Eu3+ doped tellurite glass could be a scintillator candidate used in X-ray detection field. [ABSTRACT FROM AUTHOR]

Abstract We examined the optical and luminescence properties of BaO-TiO 2 -SiO 2 (BTS) glasses and BTS glass-ceramics (GCs). The 40BaO-20TiO 2 -40SiO 2 (BTS40) GC obtained by heat treatment at glass transition temperature (T g) + 50 °C exhibited bulk crystallization, whereas surface crystallization was obtained for the 33.3BaO-16.7TiO 2 -50SiO 2 (BTS50) and 30BaO-15TiO 2 -55SiO 2 (BTS55) GCs by the same heat treatment. The photoluminescence (PL) excitation spectra changed depending on the chemical composition. After crystallization, the peaks of the PL and the scintillation spectra were blue-shifted, indicating the local coordination change of the Ti species. A large enhancement of X-ray induced scintillation was observed in the BTS40 system, though the precursor BTS40 glass exhibited lower scintillation intensity despite its higher effective atomic number (Z eff). Since the volume fraction of Ba 2 TiSi 2 O 8 crystallites in the BTS40 GC is higher than the other GCs, the enhancement in scintillation intensity reflects an increase in number density of emission centers in Ba 2 TiSi 2 O 8 crystallites after crystallization. Highlights • BaO-TiO 2 -SiO 2 glasses were prepared by a melt-quenching method. • Heat-treatment of glasses was performed at the T g + 50 °C to obtain the glass-ceramics. • Volume fraction of Ba 2 TiSi 2 O 8 decreased with increasing SiO 2 fraction. • Intensity of emission, especially X-ray scintillation, was affected by the Ba 2 TiSi 2 O 8 volume fraction in the glass-ceramics. [ABSTRACT FROM AUTHOR]

Abstract We report the synthesis and luminescence properties of new layered mixed-anion compounds, Sr 2 ScCuSeO 3 and Sr 3 Sc 2 Cu 2 Se 2 O 5. Sr 2 ScCuSeO 3 and Sr 3 Sc 2 Cu 2 Se 2 O 5 were synthesized by solid-state reaction and were investigated using x-ray diffraction, diffuse reflectance, and photoluminescence spectroscopies. Both compounds have very similar properties except for their optical band gaps and emission peak energies. At room temperature, Sr 2 ScCuSeO 3 and Sr 3 Sc 2 Cu 2 Se 2 O 5 exhibit optical band gaps energies of 2.9–3.0 eV. The excitonic luminescence with very fast emissions of ∼30 ps were observed in both compounds even at room temperature. This feature of the compounds makes them suitable for fast scintillator applications. Our results suggest that the luminescence properties such as emission peak energies and lifetimes of these layered mixed-anion compounds can be controlled by changing their structure and composition. Highlights • New layered mixed-anion compounds were successfully synthesized by solid-state reaction. • Sr 2 ScCuSeO 3 and Sr 3 Sc 2 Cu 2 Se 2 O 5 exhibit band gap energies of 2.9–3.0 eV, respectively. • Under UV excitation, Sr 2 ScCuSeO 3 and Sr 3 Sc 2 Cu 2 Se 2 O 5 exhibit a fast decay times around 30 ps even at room temperature. • Except for the emission decay, the observed optical properties are almost similar to other chalcogenide oxides. • The luminescence properties of these materials can be controlled by their composition and structure. [ABSTRACT FROM AUTHOR]

The crystal growth procedure and luminescence properties of pure and Eu 2+ -doped BaBrI and SrBrI crystals are reported. Emission and excitation spectra were recorded under ultraviolet and vacuum ultraviolet excitations. The energy of the first Eu 2+ 4f-5d transition and SrBrI band gap are obtained. The electronic structure calculations were performed within GW approximation as implemented in the Vienna Ab Initio Simulation Package. The energy between lowest Eu 2+ 5d state and the bottom of conduction band are found based on luminescence quenching parameters. The vacuum referred binding energy diagram of lanthanide levels was constructed using the chemical shift model. [ABSTRACT FROM AUTHOR]

Molybdates have applications in various fields such as phosphors, optical fibers, scintillators, magnets, sensors and catalysts. Thulium ion is an excellent blue activator and plays an important role in the design of persistent luminescent materials. This paper reports the investigation of the structural and luminescent properties of Barium Thulium Molybdate (Ba 1− x Tm x )MoO 4 microcrystals (with x = 0, 0.01 or 0.03). The scheelite-type crystalline structure was identified from XRD and Raman studies. Under ultraviolet (359 nm) excitation, photoluminescence (PL) spectra present the characteristic emission bands at 453 nm and 545 nm which are due to the D 1 2 → F 3 4 and D 1 2 → H 3 4 , 5 transitions, respectively, from Tm 3+ ions. Thermoluminescence (TL) measurements were performed with powdered samples previously irradiated with beta radiation. The depth of traps, associated with trap levels located inside the band-gap, was determined from TL data using different methods of glow curve analysis. The kinetic parameters, determined from thermoluminescent glow curves, provide evidence about a possible persistent luminescence emission from the (Ba 0.97 Tm 0.03 )MoO 4 sample. This is a potential blue-light or ultraviolet long-lasting phosphor, with a trapping level lifetime, at room-temperature (300 K), of about 6 days. [ABSTRACT FROM AUTHOR]

Polycrystalline 0.2at%Pr:Lu 3 Al 5 O 12 (Pr:LuAG) transparent ceramics were fabricated by solid-state reaction using 0.01 wt% MgO as sintering aid. The as-sintered ceramics were annealed in air at different temperatures. Optical absorption, photoluminescence, X-ray excited luminescence and pulse height spectra obtained after different annealing were compared. Modifications of the oxygen vacancy concentrations are found to govern the changes of the optical and scintillation response for annealing temperatures lower than 1000 °C, while the oxidation of Pr 3+ to Pr 4+ plays a more important role for higher temperatures. Air annealing up to 700 °C is an effective tool to improve the 5d-4f emission efficiency of MgO co-doped Pr:LuAG transparent ceramics. The highest radioluminescence intensity is obtained for the 700 °C annealed sample. At variance, higher temperature annealing leads to the deterioration of 5d-4f photoluminescence and scintillation properties because of the self-absorption of Pr 4+ and energy transfer from Pr 3+ to Pr 4+ . In addition, we find that the 4f-4f slow emission of ceramics shows different response characteristics under different irradiation sources. [ABSTRACT FROM AUTHOR]

A good quality Zr:GdTaO 4 single crystal with an 8.84 g/cm3 density, higher than the well-known dense scintillator PbWO 4 , was successfully synthesized by the Czochalski method for the first time. The effective segregation coefficient of Zr in Zr:GdTaO 4 is 0.288. The light yield and the energy resolution of Zr:GdTaO 4 are approximately the same as GdTaO 4. The scintillation decay time of Zr:GdTaO 4 contains a fast decay of 9.51 ns, close to the fast scintillator PbWO 4 , and a slow decay of 755.61 ns, which is much faster than that of GdTaO 4 whose fast decay time is 101.82 ns and slow decay time is 3290.52 ns. With Zr4+ doping, the photoluminescence band of GdTaO 4 is blueshifted and the traps are shallowed, which may help accelerate the scintillation decay. As far as we know, the Zr:GdTaO 4 single crystal is the densest scintillator with a less than 10 ns scintillation decay time, which can be used in electromagnetic calorimeters. • A Zr:GdTaO 4 single crystal with an 8.84 g/cm3 density was first synthesized. • Zr:GdTaO 4 crystal contains a fast scintillation decay of 9.51 ns, close to PbWO 4. • Blueshifted luminescence band and shallowed trap accelerate the scintillation decay. [ABSTRACT FROM AUTHOR]

Over the past two decades, substantial research has been done on the typical elpasolite scintillators Ce:Cs 2 LiYCl 6 (CLYC) and Ce:Cs 2 LiLaBr 6 (CLLB) for their potential use as neutron/gamma dual-mode detectors. Commonly, the cation or anion alloying will change the luminescence and scintillation properties of the scintillators, such as the good energy resolution of the Ce:Cs 2 LiLa(Br–Cl) 6 (CLLBC) crystal. In this work, ⌀8 mm Ce:Cs 2 Li(LaBr 6) x (YCl 6) 1-x crystals with x = 0.1, 0.2, 0.3 and 0.4 were grown by the vertical Bridgman technique. Then, ⌀25 mm Ce:Cs 2 LiLa 0.1 Y 0.9 Br 0.6 Cl 5.4 crystal was grown for its relatively high optical quality and phase purity. The luminescence and scintillation properties were also investigated. The energy resolution of Ce:Cs 2 LiLa 0.1 Y 0.9 Br 0.6 Cl 5.4 crystal was calculated to be 9.3%. The scintillation decay time were 38 ns and 623 ns under 137Cs irradiation. • Ce: Ce:Cs 2 Li(LaBr 6) x (YCl 6) 1-x crystals were grown using vertical Bridgman method. •⌀25 mm Ce:Cs 2 LiLa 0.1 Y 0.9 Br 0.6 Cl 5.4 crystal with good optical quality was obtained. • Energy levels were calculated and CVL mechanism was displayed. •The photoluminescence decay time of Ce:Cs 2 LiLa 0.1 Y 0.9 Br 0.6 Cl 5.4 crystal was 36.9 ns. •Energy resolution of 9.3% under 137Cs irradiation was obtained. [ABSTRACT FROM AUTHOR]

Luminescent nanopowders of single (Y 3 Al 5 O 12 :Ce 3+ ) and multicomponent (Lu 2 Gd 1 Al 5 O 12 :Ce 3+ ) garnets were synthesized by the solvothermal method in a high pressure autoclave. The synthesis conditions were optimized with respect to morphological and photoluminescence properties. Optimized conditions allow to synthesize well-dispersed nanoparticles with a size of some 30 nm. Concentration quenching of the Ce 3+ emission as well as luminescence quenching by surface states of nanoparticles were found and discussed. [ABSTRACT FROM AUTHOR]

We report on the efficient photoluminescence (PL) and radioluminescence (RL) of the PbI 2 nanoclusters (NCLs), which are naturally formed in the nanostructured Pb 1-X Cd x I 2 alloys (X=0.70). Here, we carried out the studies of the nature of radiative recombination processes in the NCLs of various sizes by measuring PL temperature evolution. Our results indicate that at low temperatures the PL is mainly caused by exciton emission and recombination of donor-acceptor pairs, generated in volume of large NCLs. The broad bands, which are associated with the deep intrinsic surface states, including self-trapped excitons (STEs), are dominant in the PL spectra at higher temperature (>100 K). Our work shows that the nature of emission, associated with RL bands is analogous to that for PL bands. It was shown that the investigated nanostructured material is strongly radiation-resistant. Thus, the Pb 1-X Cd X I 2 alloys can be considered as new effective layered semiconductor nanostructured materials which can be suitable for the elaboration of perspective semiconductor scintillators. These nanomaterials have promising prospects for applications in new generations of devices for biomedical diagnostics and industrial imaging applications. [ABSTRACT FROM AUTHOR]

Photo- and radioluminescence and thermally stimulated luminescence characteristics of Ce 3+ - doped and Ce 3+ , Mg 2+ co-doped Gd 3 (Ga,Al) 5 O 12 (GAGG) single crystals of similar composition are investigated in the 9–500 K temperature range. The Ce 3+ - related luminescence spectra and the photoluminescence decay kinetics in these crystals are found to be similar. Under photoexcitation in the Ce 3+ - and Gd 3+ - related absorption bands, no prominent rise of the photoluminescence intensity in time is observed neither in GAGG:Ce,Mg nor in GAGG:Ce crystals. The afterglow is strongly reduced in GAGG:Ce,Mg as compared to GAGG:Ce, and the afterglow decay kinetics is much faster. Co-doping with Mg 2+ results in a drastic decrease of the thermally stimulated luminescence (TSL) intensity in the whole investigated temperature range and in the appearance of a new complex Mg 2+ - related TSL glow curve peak around 285 K. After irradiation in the Ce 3+ - related 3.6 eV absorption band, the TSL intensity in GAGG:Ce,Mg is found to be comparable with that in the GAGG:Ce epitaxial film of similar composition. The Mg 2+ - induced changes in the concentration, origin and structure of the crystal lattice defects and their influence on the scintillation characteristics of GAGG:Ce,Mg are discussed. [ABSTRACT FROM AUTHOR]

In this work, density, optical, photoluminescence and x-ray scintillation properties of calcium gadolinium silicoborate glass (CaO:Gd 2 O 3 :SiO 2 :B 2 O 3 ) have been investigated. Glasses were prepared by the conventional melt quenching technique. The results show that the density of glass increased with increasing of Sm 2 O 3 . The optical spectra of glass shows eleven discrete absorption bands at 360, 373, 403, 475, 944, 1077, 1225, 1368, 1468, 1520 and 1586 nm which are due to the transitions of 6 H 5/2 to 4 D 3/2 , 6 P 7/2 , 6 P 3/2 , 4 I 11/2 , 6 F 11/2 , 6 F 9/2 , 6 F 7/2 , 6 F 5/2 , 6 F 3/2 , 6 H 15/2 and 6 F 1/2 , respectively. The emission spectra were observed and assigned to 312, 563, 600, 646 and 703 nm by excitation at 275 nm. The emission intensity of Sm 3+ increased with increasing of Sm 2 O 3 concentration until 0.25 mol%, while decay time decrease with increasing of Sm 2 O 3 content. For results of the radioluminescence (RL), they perform four emission peaks with the strongest emission at 598 nm. Glass doped with 0.35 mol% Sm 2 O 3 show the highest RL emission. The integral scintillation efficiency of 0.35 mol% Sm 2 O 3 doped glass was determined as 25% of commercial BGO scintillator crystal. [ABSTRACT FROM AUTHOR]

Ce3+/ Gd3+ co-doped NaBaBO 3 blue luminescent materials were synthesized by the solid-state reaction. Research shows that Ba2+ ions with larger ionic radius are replaced by Gd3+ ions and Ce3+ ions with smaller ionic radii. Gd3+ can act as a sensitizer to absorb energy and promote the luminescence of Ce3+.Under the excitation of 360 nm near ultraviolet light and X-ray, NaBaBO 3 :0.03Gd3+, 0.01Ce3+ can emit bright blue light, and its emission peak is located at 430 nm. [Display omitted] Ce3+ and Gd3+ co-doped NaBaBO 3 blue luminescent materials were synthesized by the solid-state reaction. X-ray diffraction, X-ray photoelectron spectrometer, and fluorescence spectrometer were used to analyze the crystal structure, the surface morphology, and the luminous properties. Ce3+/Gd3+ co-doped NaBaBO 3 phosphors can absorb near-ultraviolet light and emit bright blue light centered at 430 nm, which originates from the 5d-4f transition of Ce3+ ion. When the doping concentration of Ce3+ and Gd3+ was 1 % and 3 % respectively, Ce3+/Gd3+doped NaBaBO 3 had the strongest luminous intensity with a short decay time of about 23 ns. The addition of Gd3+ increases the luminescence intensity of Ce3+ doped NaBaBO 3. The CIE color coordinates are (0.1564, 0.0909). Ce3+/Gd3+ co-doped NaBaBO 3 powders are promising materials for WLEDs and scintillators. [ABSTRACT FROM AUTHOR]

(C 6 H 5 C 2 H 4 NH 3) 2 PbBr 4 single crystals substituted with various concentrations of In (5, 10, 25, and 50%) were grown by the solvent diffusion method, and the effect of In-substitution on photoluminescence (PL) and scintillation properties were investigated. PL and scintillation peaks due to excitons confined in inorganic layers were observed, and the decay times were consistent with those of the free excitonic luminescence. The photoluminescence quantum yields of the 5, 10, 25, and 50% In-substituted crystals were respectively 23.0, 24.7, 26.0, and 25.2%. The light yield of the 25% In-substituted crystal was estimated to be 14100 photons/MeV from the pulse height spectrum under 137Cs γ-rays irradiation. • In:(C 6 H 5 C 2 H 4 NH 3) 2 PbBr 4 crystals were grown by the solvent diffusion method. • Free excitonic luminescence was observed. • Light yield of the 25% In-substituted crystal was 14,100 photons/MeV. [ABSTRACT FROM AUTHOR]

Temperature dependences of the intensity and decay kinetics of the Ce 3+ - related photoluminescence and characteristics of thermally stimulated luminescence are investigated in the 77–500 K temperature range for the epitaxial films of the multicomponent garnets of the type of Lu 3−x Gd x Ga y Al 5−y O 12 :Ce with Ce content of 0.3–0.7 at. %, where x varies from 0.14 to 3 and y varies from 0 to 3.54. Different methods are used for the determination of energy distances between the excited 5d 1 and 5d 2 levels of Ce 3+ ions and the conduction band (CB) and their applicability is compared. The dependences of the 5d 1,2 – CB energy distances on the multicomponent garnet composition are clarified. The 5d 1 – CB energy distance is found to decrease by about an order of magnitude with the increasing Ga 3+ content. The most drastic decrease, observed at the Ga 3+ content around y ≈ 1.7, is suggested to arise from the change in the Ga 3+ position from the smaller tetrahedral to larger octahedral Al 3+ sites. This effect is explained by the lattice distortion due to the substitution of smaller Lu 3+ and Al 3+ ions by larger Gd 3+ and Ga 3+ ions. Application potential of these epitaxial films for fast 2D-imaging is discussed. [ABSTRACT FROM AUTHOR]

Optical, scintillation, and dosimetric properties of the undoped and Tb-doped CaYAlO 4 single crystals grown by the floating zone method were evaluated. Several photoluminescence (PL) emission peaks due to the 4f–4f transitions of Tb3+ ion were observed at 385–620 nm under excitation at 250 nm in Tb-doped CaYAlO 4 samples. Under X-ray irradiation, scintillation peaks of the Tb-doped CaYAlO 4 crystals were consistent with the PL emission peaks. In terms of a dosimetric property, the 0.1% Tb-doped crystal exhibited the highest thermally stimulated luminescence intensity and the widest linear responses in the range of 0.01–1000 mGy among the samples. • The undoped and Tb-doped CaYAlO 4 single crystals were synthesized by the floating zone method. • The Tb-doped samples exhibited luminescence due to the 4f-4f transitions of Tb3+. • The 0.1% Tb-doped crystal exhibited the widest linear responses in the range of 0.01–1000 mGy among the samples in TSL. [ABSTRACT FROM AUTHOR]

Fluoroborosilicate (SBF anc :SiO 2 + B 2 O 3 +AlF 3 + NaF + CaF 2) glasses with different CeF 3 concentrations were fabricated by melt quenching technique to examine the scintillation properties of these glasses. The density and refractive index increase with an increase in CeF 3 concentration. The structural properties of glasses were studied in the range of 800–4000 cm−1 using FT-IR transmittance spectroscopy. Luminescence characteristics of Ce3+:SBF anc glasses with an intensity peak around ∼345 nm (5d→4f) were studied using photo (λ exc = 303 nm) and X-ray excited luminescence techniques. The energy transfer (ET) between Ce3+ -Ce3+ ion pairs taking place via dipole-dipole type interaction for the concentration quenching of Ce3+ emission on the basis of Dexter and Schulman theory. The PL decay curves can be fitted by a double exponential function with the decay times 64.28–99.87 ns and 15.78–21.29 ns for slow and fast decay components, respectively. The highest integrated light emission intensity of Ce3+:SBF anc glasses stimulated by X-ray is 35% of commercial Bi 4 Ge 3 O 12 crystal and can be used for the scintillator materials. • The transmittance spectra of glasses were measured in UV, Visible and mid-IR region. • Concentration quenching of Ce3+ emission is analyzed by the Dexter-Schulman theory. • PL, X-ray excited luminescence and decay curves of glasses were investigated. • The X-ray intensity of SBF anc Ce 0.30 glass is about 35% of that of a commercial BGO. [ABSTRACT FROM AUTHOR]

The Tm-doped MgAl 2 O 4 single crystals were synthesized by using Xe arc lamps-equipped floating zone furnace. The synthesized crystals exhibited luminescence due to the 4f-4f transitions of Tm3+ in photoluminescence (PL), scintillation, and thermally stimulated luminescence (TSL). In all of PL, scintillation, and TSL, the 0.5% Tm-doped crystal showed the highest luminescence intensity. In TSL dose response functions, the 0.5% Tm-doped crystal showed sensitivity from X-ray irradiation with 0.1 mGy. In addition, we measured linear energy transfer (LET) dependence on TSL glow curve of the crystal and X-ray imaging test taken by TSL. We revealed the spatial resolution of the crystal was 100 μm. • We have characterized the photoluminescence, scintillation, and dosimetric properties of Tm-doped MgAl 2 O 4 single crystals. • All the crystals showed luminescence properties due to Tm3+ ion. • We revealed possibility of Tm-doped MgAl 2 O 4 crystal for personal dosimetry, 2D dosimetry, and heavy ion beam measurement. [ABSTRACT FROM AUTHOR]

Fast energy transfer from Yb2+ to Sm2+ is a requirement when using Yb2+ as a sensitiser for Sm2+ emission for near-infrared scintillator applications. This cannot be achieved through dipole-dipole interactions due to the spin-forbidden nature of the involved Yb2+ transition, making the rate of energy transfer too slow for application. This work explores whether exploiting the exchange interaction by increasing the Yb2+ concentration to 99% is an effective way to increase the rate at which energy is transferred from Yb2+ to Sm2+. The scintillation characteristics of CsYbBr 3 :1%Sm, CsYbI 3 :1%Sm and YbCl 2 :1%Sm single crystals were studied through 137Cs excited pulse height spectra, X-ray excited decay and X-ray excited luminescence spectra. An energy resolution of 7% and a light yield of 30,000 ph/MeV was achieved with CsYbI 3 :1%Sm. Photoluminescence spectroscopy and decay studies were performed to study the band structure and relaxation dynamics. • Energy transfer from Yb2+ to Sm2+ happens on a subnanosecond timescale. • Detection of 20,000 photons in the 662 keV photopeak for CsYbI 3 :1%Sm. • A 7% energy resolution was achieved with CsYbI 3 :1%Sm. • Sm2+ emission intensity of all samples is stable between 78 K and 700 K. [ABSTRACT FROM AUTHOR]

The standard melt-quenching technique was used to create a novel series of Gd3+ and Sm3+co-doped borate glasses with the LAGdxBSm1.0 and LAGd2.5BSmx series of glasses. All samples were analyzed by XRD, FTIR, and optical screening to determine their characteristics (absorption, excitation, and emission). The results confirmed the amorphous nature of the synthesized glass samples, while the FTIR revealed the existence of BO 3 , and BO 4 vibrations in the samples. The series glass quality of LAGdxBSm1.0 doped in the host matrix was confirmed by the radioluminescence and photoluminescence results at the optimal doping concentration of 2.5 mol%. The decay of samples was investigated to determine the relationship between doping concentration and luminescence characteristics. Glasses have been created into an appropriate lighting glass using 25Li 2 O-5Al 2 O 3 -2.5Gd 2 O 3 -(67.5-X)B 2 O 3 -XSm 2 O 3 host matrix glass doped with varying concentrations of Sm3+. Visible light and near-infrared absorption values in the glass samples demonstrate the existence of Sm3+ions. The photoluminescence and radioluminescence spectra have high concentration quenching (0.5 mol%) and produce four emission peak wavelengths, with the maximum emission wavelength at 600 nm (soft orange color). Based on these results, the studied glass series could be a good choice for X-ray scintillators in medical, industrial, and other settings in the future. • Gd3+/Sm3+ co-doped in borate glasses were developed. • The optimum concentration of Gd 2 O 3 was observed at 2.5 mol%. • Sm 2 O 3 0.5 mol% is the quenching concentration confirmed by the luminescence. • The XANES spectra confirmed the trivalent oxidation state of Sm. [ABSTRACT FROM AUTHOR]

The bright reddish-orange emitting Eu3+-doped gadolinium borate glasses of 25Gd 2 O 3 -(75-x) B 2 O 3 -xEu 2 O 3 (GdBEu) (x = 0.1, 0.3, 0.5, 1.0, 3.0, 5.0, 7.0, and 9.0 mol%) were fabricated by melt-quenching technique at 1400 °C for 3 h. All GdBEu glasses were investigated the photoluminescence, scintillation, and lasing potential properties. The energy transfer processes from Gd3+→Eu3+ in these glasses were discovered. Photons in the ultraviolet, visible, and near-infrared region wavelengths were absorbed by glasses. The photoluminescence excitations were performed at 275 nm and 394 nm, respectively. When the energy transferred from Gd3+ to Eu3+, luminescence features revealed an intense red emission with a wavelength of 614 nm (5D 0 → 7F 2). The glass's optimum Eu3+ ion concentration was 7.0 mol%, corresponding to the maximum emission intensity. Judd-Ofelt parameters were calculated from the emission spectra and the radiative properties of several excited states were examined, including the transition probability (A R), branching ratio (β R), stimulated emission cross-section (σ e), and decay time (τ R). Once the Eu3+ concentration increased from 0.1 to 9.0 mol%, the decay time of the 5D 0 level dropped from 1.824 ms to 1.585 ms. The colors of glasses were confirmed by the Commission internationale de l'éclairage (CIE) chromaticity diagram. The glass samples had a peak area of radioluminescence (RL) spectrum 18% of BGO scintilltation crystal. • Gadolinium borate glasses doped with Eu3+ were synthesized. • The emission transitions from 5D 0.→ 7F 1,2,3,4 observed. • Emission intensities increased up to 7% of the Eu 2 O 3. • Maximum integral scintillation efficiency was 18% compared BGO. [ABSTRACT FROM AUTHOR]

Hafnium-based materials are attractive for a scintillator owing to their high density and effective atomic number. In this study, single crystals of Ce-doped calcium hafnate perovskite (Ce:CaHfO 3) were synthesized from a Ca-rich composition, and photoluminescence (PL) and scintillation properties were investigated. The X-ray diffraction patterns revealed that the synthesized single crystals were a single phase of CaHfO 3. The Ce:CaHfO 3 exhibited blue luminescence at 430 nm and fast decay due to the 5d–4f transition of Ce3+ in both PL and scintillation. From the measurement of pulse height spectra under 137Cs irradiation, the highest light yield of 7800 photons/MeV was observed in the 3% Ce:CaHfO 3. • Single crystals of Ce-doped calcium hafnate perovskite (Ce:CaHfO 3) were successfully synthesized from a Ca-rich composition. • Ce:CaHfO 3 exhibited blue luminescence and fast decay due to the 5d–4f transition of Ce3+ in both PL and scintillation. • The light yield of 7800 photons/MeV was observed in the 3% Ce:CaHfO 3 under 137Cs gamma-ray irradiation. [ABSTRACT FROM AUTHOR]

The CeF 3 doped Gd 2-x MoB 2 O 9 phosphors (where x = 0.00, 0.25, 0.50 and 0.75 mol%) were synthesized by the conventional high-temperature solid-state reaction method at 900 °C for 12 h in air. DSC and TGA analysis executed to study the optimum temperature for sintering. The structural, photoluminescence and X-ray luminescence properties were investigated. The structure of the samples was analyzed by using X-ray diffractometer (XRD). The absorption spectra were analyzed and found that absorption edge increased with the increasing concentration of CeF 3. The photoluminescence of phosphors shows the overlapping of excitation and emission peaks in the range of 300 nm–450 nm. These emission peak correspond to the 5d – 4f transitions of Ce3+ ion. The optimum concentration of CeF 3 in these phosphors is 0.50 mol% corresponding to maximum emission intensity. The X-ray induced optical luminescence spectra showed a strong emission peak at 411 nm the concentration quenching at 0.75 mol%, which is as efficient as 54.4% compared with bismuth germanium oxide (BGO) crystal. The luminescence decay increased with the increment of CeF 3 concentration. From the optical properties investigated, it was found that the phosphors performed a strong and fast luminescence signal which is appropriate for the development of scintillators in X-ray detector devices. • Synthesis of phosphors doped Ce3+ ion for photonic and scintillation materials applications. • The strong emission spectra at 411 nm were observed. • The Decay time of the phosphors with the highest emission intensity (5d.→ 4f transition) was 12.35 ns • Highest X-ray-induced luminescence intensity is 411 nm of Ce3+ ion at the 5d.→ 4f transition. • The integral scintillation efficiency of phosphors was 54.44% of the BGO crystal. [ABSTRACT FROM AUTHOR]

Cerium doped Barium Fluoride (BaF 2 Ce) transparent ceramic was fabricated and its luminescence and scintillation properties were studied. The photoluminescence shows the emission peaks at 310 nm and 323 nm and is related to the 5d-4f transitions in Ce 3+ ion. Photo peak at 511 keV and 1274 keV were obtained with BaF 2 Ce transparent ceramic for Na-22 radioisotopes. Energy resolution of 13.5% at 662 keV is calculated for the BaF 2 Ce transparent ceramic. Light yield of 5100 photons/MeV was recorded for BaF 2 Ce(0.2%) ceramic and is comparable to its single crystal counterpart. Scintillation decay time measurements shows fast component of 58 ns and a relatively slow component of 434 ns under 662 keV gamma excitation. The slower component in BaF 2 Ce(0.2%) ceramic is about 200 ns faster than the STE emission in BaF 2 host and is associated with the dipole-dipole energy transfer from the host matrix to Ce 3+ luminescence center. [ABSTRACT FROM AUTHOR]

Evolution of the non-radiative and radiative recombination in GaN and CdS 2.5–20 μm thick layers has been examined by the in situ measurements of the 1.6 MeV proton induced luminescence and laser excited photoconductivity characteristics. The introduction rate of radiation defects has been evaluated by the comparative analysis of the laser and proton beam induced luminescence for the examined GaN and CdS layers. [ABSTRACT FROM AUTHOR]

Mg2+-codoped Y 0.6 Gd 2.4 Al 2 Ga 3 O 12 :Ce (YGAGG:Ce,Mg) single crystal was grown by the Czochralski method and its luminescence and scintillation properties were investigated. Temperature dependence of radioluminescence (RL) yield and photoluminescence (PL) decay time was measured, and activation energy of thermal ionization process was determined from temperature-dependent PL decay time measurement. YGAGG:Ce,Mg exhibited high X-ray excited RL yield almost 5 times higher than BGO reference scintillator. Its light yield of 41,500 ph/MeV and scintillation decay times of 12 ns (2%) + 52 ns (65%) + 207 ns (33%) were measured under excitation with 662 keV γ rays from 137Cs source. Afterglow and thermally stimulated luminescence characteristics are also investigated. • Luminescence and scintillation properties of Y 0.6 Gd 2.4 Al 2 Ga 3 O 12 :Ce,Mg crystal are investigated. • Temperature dependence of photo-and radioluminescence are presented. • Y 0.6 Gd 2.4 Al 2 Ga 3 O 12 :Ce,Mg shows high light yield of 41,500 photons/MeV. • Luminescence quenching above RT can be caused by thermal ionization. • Afterglow and thermoluminescence characteristics are investigated. [ABSTRACT FROM AUTHOR]

Lanarkite type Pb 2 MoO 5 single crystals were grown using low temperature gradient Czochralski technique and their optical and luminescent properties were studied. The luminescence band at 590–600 nm was observed under UV and X-ray excitations and ascribed to emission of self-trapped excitons. The band is thermally quenched at T > 15 K with the activation energy of process, E act = 11 meV. The measurements of thermostimulated luminescence demonstrated the presence of shallow traps, which adversely influence the energy transfer to the emission centers. [ABSTRACT FROM AUTHOR]

Single crystals of Ce-doped Cs 3 LaCl 6 and Cs 3 LaBr 6 show promising scintillation properties in gamma-ray detection. Their thermal response in the range from 40 K to 500 K is discussed in this work. The steady state photoluminescence spectra, photoluminescence decay time, and X-ray excited radioluminescence of Ce-doped and undoped Cs 3 LaCl 6 and Cs 3 LaBr 6 were studied. The photoluminescence and radioluminescence emission intensity of the Ce-doped crystals decreases less than 25% from 40 K to 500 K. The photoluminescence decay time of Ce 3+ increases with increasing temperature. [ABSTRACT FROM AUTHOR]