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The photoluminescence (PL) and scintillation properties of Ce-doped BaHfO3 crystals were investigated. The Ce-doped BaHfO3 crystal is transparent and colorless after annealing treatment under a reduction condition. The broad luminescence band at ~370 nm was observed under ~280 nm excitation with the decay time of ~17 ns. The X-ray-induced scintillation spectra also showed the broad luminescence band at ~380 nm with a fast decay. The origin of the broad luminescence band at ~380 nm is attributed to the 5d-4f transition of Ce3+. The pulse height distribution under 137Cs gamma ray irradiation using Ce-doped BaHfO3 exhibited a distinguishable photoabsorption peak. The light yield of Ce-doped BaHfO3 is ~1600 photons/MeV. [ABSTRACT FROM AUTHOR]

The photoluminescence (PL), scintillation, and thermally stimulated luminescence (TSL) properties of Eu-doped (0.01, 0.1, and 1%) Al2O3 single crystals grown by the floating zone method were investigated systematically. The PL of the samples showed several sharp emission peaks across 550-750 nm originating from the 4f-4f transitions of Eu3+ and the 3d-3d transitions of Cr3+ impurity ions. The scintillation spectrum of the samples showed a broad emission peak at 320 nm due to the F+ center and an emission peak at 700 nm due to the 3d-3d transitions of Cr3+ impurity ions. All the samples showed TSL glow peaks at around 200, 320, and 375 °C. The TSL intensity of the 1% Eu-doped sample was the highest among the present three samples, and the TSL response was proportional to the irradiated X-ray dose in the range from 10 to 1000 mGy. The Eu-doped Al2O3 single crystal could be a novel candidate for personal dose monitoring applications. [ABSTRACT FROM AUTHOR]

Copper (I) based halide scintillators have received high attention due to their high light yield. At the same time, researchers are increasingly interested in exploring organic‐inorganic hybrid copper(I) based halides, due to the diversity and tunability of structures. Here, we describe high‐efficiency photoluminescence and X‐ray excited luminescence in (DFPD)3Cu2I5 (1) (DFPD=4,4‐difluoro‐bipiperidinium). 1 is comprised of a unique [Cu2I5]3− cluster, which have typical structure allowing high‐transition‐probability self‐trapped exciton emission (one Cu+ ion adopts the tetrahedral coordination geometry, the other trigonal planar coordination geometry, the Cu−Cu distance (2.574 Å) is short). Accordingly, 1 shows efficient yellow‐green photoluminescence with the maximum at 527 nm, a full‐width at half‐maximum of 99.2 nm, a large Stokes shift of 214 nm (1.6 eV) and a quantum yield of 77.15 %. Polycrystalline 1 can also convert high‐energy X‐ray photons into UV‐visible pulsed fluorescence with the light yield of 5000 photons/MeV. This finding plays a valuable role in the development of organic‐inorganic hybrid copper(I) based scintillators. [ABSTRACT FROM AUTHOR]

Copper (I) based halide scintillators have received high attention due to their high light yield. At the same time, researchers are increasingly interested in exploring organic‐inorganic hybrid copper(I) based halides, due to the diversity and tunability of structures. Here, we describe high‐efficiency photoluminescence and X‐ray excited luminescence in (DFPD)3Cu2I5 (1) (DFPD=4,4‐difluoro‐bipiperidinium). 1 is comprised of a unique [Cu2I5]3− cluster, which have typical structure allowing high‐transition‐probability self‐trapped exciton emission (one Cu+ ion adopts the tetrahedral coordination geometry, the other trigonal planar coordination geometry, the Cu−Cu distance (2.574 Å) is short). Accordingly, 1 shows efficient yellow‐green photoluminescence with the maximum at 527 nm, a full‐width at half‐maximum of 99.2 nm, a large Stokes shift of 214 nm (1.6 eV) and a quantum yield of 77.15 %. Polycrystalline 1 can also convert high‐energy X‐ray photons into UV‐visible pulsed fluorescence with the light yield of 5000 photons/MeV. This finding plays a valuable role in the development of organic‐inorganic hybrid copper(I) based scintillators. [ABSTRACT FROM AUTHOR]

The paper presents the results of a comprehensive study of the structural-phase composition, morphology, optical, luminescent, and scintillation characteristics of thick ZnO films fabricated by magnetron sputtering. By using a hot ceramic target, extremely rapid growth (~50 µm/h) of ZnO microfilms more than 100 µm thick was performed, which is an advantage for the industrial production of scintillation detectors. The effects of post-growth treatment of the fabricated films in low-temperature plasma were studied and a significant improvement in their crystalline and optical quality was shown. As a result, the films exhibit intense near-band-edge luminescence in the near-UV region with a decay time of <1 ns. Plasma treatment also allowed to significantly weaken the visible defect luminescence excited in the near-surface regions of the films. A study of the luminescence mechanisms in the synthesized films revealed that their near-band-edge emission at room temperature is formed by phonon replicas of free exciton recombination emission. Particularly, the first phonon replica plays the main role in the case of optical excitation, while upon X-ray excitation, the second phonon replica dominates. It was also shown that the green band peaking at ~510 nm (2.43 eV) is due to surface emission centers, while longer wavelength (>550 nm) green-yellow emission originates mainly from bulk parts of the films. [ABSTRACT FROM AUTHOR]

Alkali metal halides have long been used as scintillators for applications as sensors and detectors. Usually, a small amount of impurities are added to these inorganic materials to improve their luminescence efficiencies. We investigate the structures and luminescent properties of un-doped sodium iodide (NaI) and cesium-doped NaI (NaI:Cs) films deposited by thermal vacuum evaporation. Instead of using the toxic element thallium (Tl), we introduced cesium dopant into NaI. This is the first study for the NaI:Cs film excited by UV LED's ultraviolet C (273 nm, 4.54 eV). The luminescence spectra show two main peaks at 3.05 and 4.32/3.955 eV (for fused silica/B270 substrate), originating from the intrinsic defects and/or activator excited states and the intrinsic self-trapped excitons (STEs), respectively. In general, both Cs-doping and post-annealing processes enhance the luminescence performance of NaI films. [ABSTRACT FROM AUTHOR]

The purpose of this research is to investigate the luminescence and scintillation properties of mixed halide scintillators K2LaBr5-xIx. The crystals of K2LaBr5-xIx:2% Ce (x = 0, 1, 2) have been synthesized by high-temperature solid-phase method and grown by vertical Bridgman method. The crystals are measured by X-ray induced luminescence spectra, optical transmittance photoluminescence spectrum, photoluminescence decay time, and pulse height spectrum. Under the UV and X-ray excitation, all of the crystal samples have typical Ce3+ double peaks corresponding to the energy level shifts of 5d1→2F5/2 and 5d1→2F7/2, with emission centers ranging from 350 to 400 nm. The photoluminescence decay time of the three crystals of K2LaBr5-xIx: Ce is about 20 ns. Under 662 keV γ-rays excitation from a 137Cs source, the energy resolution is 8.2%, 15% and 10% (FWHM), respectively. [ABSTRACT FROM AUTHOR]

The optical, photo, and X-ray luminescence properties of Sm3+ ion-doped Li2O-Al2O3-Gd2O3-B2O3-P2O5 glasses are evaluated. The glasses are fabricated by the melt quenching technique. The absorption spectra exhibit the hypersensitive transitions 6H5/2→6P3/2 and 6H5/2→6F7/2 0at the visible and near-infrared range respectively. The glasses display four major transitions characteristic of Sm3+ ion for photoluminescence and X-ray luminescence, with the most intense one corresponding to the 4G5/2→6H7/2 transition. The best emitting samarium concentration obtained by X-ray excitation is compared to BGO crystals. The integral scintillation efficiency of glass is determined by total area under all of peak spectrum. The results indicate the promising application of these glasses in scintillators and for X-ray sensing devices. [ABSTRACT FROM AUTHOR]

Gallium nitride is a wide-direct-bandgap semiconductor suitable for the creation of modern optoelectronic devices and radiation tolerant detectors. However, formation of dislocations is inevitable in MOCVD GaN materials. Dislocations serve as accumulators of point defects within space charge regions covering cores of dislocations. Space charge regions also may act as local volumes of enhanced non-radiative recombination, deteriorating the photoluminescence efficiency. Surface etching has appeared to be an efficient means to increase the photoluminescence yield from MOCVD GaN materials. This work aimed to improve the scintillation characteristics of MOCVD GaN by a wet etching method. An additional blue photo-luminescence (B-PL) band peaking at 2.7–2.9 eV and related to dislocations was discovered. This B-PL band intensity appeared to be dependent on wet etching exposure. The intensity of the B-PL was considerably enhanced when recorded at rather low temperatures. This finding resembles PL thermal quenching of B-PL centers. The mechanisms of scintillation intensity and spectrum variations were examined by coordinating the complementary photo-ionization and PL spectroscopy techniques. Analysis of dislocation etch pits was additionally performed by scanning techniques, such as confocal and atomic force microscopy. It was proved that this blue luminescence band, which peaked at 2.7–2.9 eV, is related to point defects those decorate dislocation cores. It was shown that the intensity of this blue PL band was increased due to enhancement of light extraction efficiency, dependent on the surface area of either single etch-pit or total etched crystal surface. [ABSTRACT FROM AUTHOR]

Ce-doped 20CsBr-20BaBr2-60ZnBr2 glasses were synthesized by the conventional melt quenching method, and their photoluminescence (PL) and scintillation properties were investigated. In the PL and scintillation spectra, all the Ce-doped glasses showed broad emissions due to the 5d-4f transitions of Ce3+ ions. Under 241Am α-rays, the light yield of 0.05% Ce-doped glass was 40 photons/5.5 MeV-α. [ABSTRACT FROM AUTHOR]

We synthesized 20Lu2O3-30Ga2O3-50SiO2 glasses doped with various concentrations of Sn using a floating zone furnace equipped with Xe arc lamps. The samples showed a luminescence band around 450 nm in both photoluminescence (PL) and scintillation spectra. The origin of the luminescence was ascribed to the T1-S0 transition of Sn2+ on the basis of the luminescence wavelength and PL decay time constant. The highest scintillation intensity and PL quantum yield were observed from the 1% Sn-doped sample. The afterglow level tended to decrease with increasing Sn doping, and the afterglow levels of the 1 and 3% Sn-doped samples were comparable to that of the conventional Tl-doped CsI scintillator. The optimal concentration of Sn for the glass was estimated to be 1%. [ABSTRACT FROM AUTHOR]

A comparative study on the radioluminescence properties of Ce-doped SrAl2O4 single crystal and translucent ceramic was performed. The transmittance of the synthesized ceramic is 20-30% in the visible region. Both samples exhibit photo- and radioluminescence with a broad emission peaking at 380 nm. The decay curves are fitted by a single exponential decay function with decay time constants of 30-50 ns, consistent with the typical value of the emission for the 5d-4f transitions of Ce3+. From the pulse height spectra measured under 241Am γ-ray (59.5 keV) irradiation, the scintillation light yields are 17000 ph/MeV for the single crystal and 6100 ph/MeV for the synthesized ceramic. The scintillation light yield and afterglow of the present samples show a negative correlation. [ABSTRACT FROM AUTHOR]

Ce:(MgxCa1-x)HfO3 (x = 0.5, 2.5, 5, and 10%) single crystals were successfully grown by the floating zone method, and their photoluminescence (PL) and scintillation properties were investigated. A broad luminescence band with a maximum at 430 nm was observed in both the PL and scintillation spectra. The PL quantum yield (QY) improved with the substitution of Mg, and the PL QY of Ce:(MgxCa1-x)HfO3 reached 50%. Fast decay due to the 5d-4f transition of Ce3+ was observed for both the PL and scintillation. Ce:(MgxCa1-x)HfO3 (x = 5%) showed the highest light yield of ~9500 photons/MeV among the synthesized samples, and this value is higher than that of common X- and gamma-ray detection scintillators such as Bi4Ge3O12 and Ce:Gd2SiO5 single crystals. [ABSTRACT FROM AUTHOR]

Novel near-infrared (NIR) phosphors are in demand for light-emitting diode (LED) devices to extend their suitability for new applications and, in turn, support the sustainable and healthy development of the LED industry. The Cr3+ has been used as an activator in the development of new NIR phosphors. However, one main obstacle for the Cr3+-activated phosphors is the low luminescence efficiency due to the spin-forbidden d-d transition of Cr3+. The rare-earth (RE) huntite minerals that crystallize in the form of REM3(BO3)4 (M = Al, Sc, Cr, Fe, Ga) have a large family of members, including the rare-earth scandium borates of RESc3(BO3)4. Interestingly, in our research, we found that the luminescence efficiency of Cr3+ in the CeSc3(BO3)4 host, whose quantum yield was measured at 56%, is several times higher than that in GdSc3(BO3)4, TbSc3(BO3)4, and LuSc3(BO3)4 hosts. Hereby, the energy conversion and transfer in the luminescence of CeSc3(BO3)4:Cr3+ phosphor were examined. The Stokes shift of electron energy conversion within the Cr3+ 4T2g level for the emission at 818 nm and excitation at 625 nm in CeSc3(BO3)4 host was evaluated to be 3775.1 cm−1, and the super-large splitting energy of the 2F5/2 and 2F72 sub-states of the Ce3+ 4f1 state, about 3000 cm−1, was found in CeSc3(BO3)4 host. The typical electronic thermal vibration peaks were observed in the excitation spectra of CeSc3(BO3)4:Cr3+. On this basis, the smallest phonon energy, around 347.7 cm−1, of the CeSc3(BO3)4 host was estimated. Finally, the energy transfer that is responsible for the far higher photoluminescence of Cr3+ in CeSc3(BO3)4 than in other hosts was proven through the way of Ce3+ emission and Cr3+ reabsorption. [ABSTRACT FROM AUTHOR]

In recent years, Cs2ZnCl4 crystal has become an ideal substrate for various functional doped ions due to its large bandgap, showing potential in photodetectors and scintillators. In practical application, the intrinsic defect luminescence of bulk crystals has an important effect on the photoelectrical properties. In this work, Ø12 mm × 90 mm Cs2ZnCl4 single crystal was grown by the vertical Bridgman method. The theoretical bandgap, state density distribution, and refractive index curve of the crystal were obtained by first-principles calculation of the structure data. The luminescence properties of the crystal were characterized, including photoluminescence spectrum and radioluminescence spectrum. The temperature-dependent photoluminescence spectrum of the crystal was studied, and the luminescence process of the defects in the crystal was analyzed by the experimental results. [ABSTRACT FROM AUTHOR]

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]

We have developed Eu:BaFCl ceramics with translucency and investigated the optical and scintillation properties. The emission peaks appeared at around 365 and 390 nm in Eu:BaFCl translucent ceramics. Photoluminescence and scintillation decay time constants were approximately 0.5 and 6 μs, which was typical value s of Eu:BaFCl. The afterglow levels were 50–80 ppm, which was superior to commercial Tl:CsI assessed in the same setup. Under 137Cs γ-ray irradiation, the scintillation light yield of the 0.1, 0.5, and 1.0 % Eu:BaFCl were calculated to be 9,000, 16,000, and 13,000 ph/MeV, respectively. The light yield of our translucent ceramic samples was shown to be much higher than that of the Eu:BaFCl single crystal (883 ph/MeV). • Eu-doped (0.1, 0.5, and 1.0 %) BaFCl translucent ceramics were synthesized by the spark plasma sintering method. • Eu:BaFCl samples showed blue luminescence with the maximum peak at 390 nm in both the photoluminescence and X-ray-induced scintillation spectra. • The 0.5 % Eu:BaFCl sample showed the highest light yield (16,000 ph/MeV) under 137Cs γ-ray irradiation. [ABSTRACT FROM AUTHOR]

This study investigates the potential of Gd-Ba-Na borate glasses doped with Sm3+ ions as scintillation materials. The glasses were synthesized using a melt-quenching process, and their luminescence properties were examined. The results demonstrate that the glass sample with 0.5 mol% of Sm3+ exhibits the most promising scintillation performance, achieving the highest integral scintillation efficiency (24.11%) compared to the BGO crystal. For the photoluminescence study, the emission spectra, under 403 nm excitation wavelength, show emission bands centered at 563, 599, 646, and 706 nm, consistent with characteristic Sm3+ transitions. The highest energy transfer efficiency from Gd3+ to Sm3+ (64.37%) is also found in the glass sample with 0.5 mol% Sm3+. The emission color can be tuned by varying the excitation wavelength. Excitation at 403 nm primarily excites Sm3+ ions, resulting in orange emission. In contrast, excitation at 275 nm excites Gd3+ ions, leading to reddish-orange emission. The results demonstrate the potential of this glass composition for use as a highly efficient scintillation material due to its excellent performance in both radioluminescence and photoluminescence properties. • Sm3+-doped gadolinium barium sodium borate glasses have been prepared. • The integral scintillation efficiency of glass is 24.11% of BGO crystal. • The radioluminescence and photoluminescence emission reaches a maximum at 0.5 mol% of Sm3+. • The (x,y) color coordinate of emission light is located in orange region. [ABSTRACT FROM AUTHOR]

In this work, we compare the luminescence results obtained on InGaN/GaN multiple quantum well (QW) structures with different numbers of QWs. Structures are designed for scintillating applications, where large QW number covering particle penetration depth is necessary, and fast luminescence response is required. Special attention is devoted to increase the intensity of fast excitonic QW emission and to decrease the luminescence of the QW defect band, which has slower luminescence response and is undesired for fast scintillator applications. We found that increasing the In content in QWs suppresses the defect band luminescence and decreasing the QW growth rate increases the photoluminescence (PL) intensity of excitonic luminescence. We also show that increasing the number of InGaN further improves the PL properties of InGaN QWs. The photoluminescence and cathodoluminescence characteristics are compared and discussed. [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]

The photoluminescence (PL) and scintillation properties of (C6H5C2H4NH3)2Pb1-xCuxBr4 (x = 0.05, 0.1, 0.25, and 0.5) single crystals prepared by the poor-solvent diffusion method were evaluated. In the PL profiles, free- and bound-exciton luminescence peaks at 410 and 440 nm were observed, respectively. The PL quantum yields (QYs) of the x = 0.05, 0.1, 0.25, and 0.5 samples were 20.0, 19.3, 18.4, and 16.7% with 2% errors, respectively. In the scintillation profiles, a bound-exciton luminescence peak was observed at 440 nm. Under γ-ray exposure with 137Cs, a photoabsorption peak was observed in all the samples, and the scintillation light yields of the x = 0.05, 0.1, 0.25, and 0.5 samples were estimated to be ~12000, ~11000, ~10000, and ~9700 ph/MeV with 10% errors, respectively. [ABSTRACT FROM AUTHOR]

In recent years, several coordination polymers of different dimensions and metal–organic frameworks were tested and expected to be good candidates for closing the gap between organic and plastic scintillators on the one hand side and inorganic scintillators on the other hand side. In the present work, we report the synthesis and characterization of a novel one-dimensional scintillating coordination polymer based on cadmium(II), N,N'-(1,4-phenylenedicarbonyl)di-glycinate, and 2,2'-bipyridine. Crystals could be obtained from water–methanol solutions and the structure was determined by single-crystal diffraction. The coordination polymer exhibits scintillation under X-ray excitation and laser as well as UV-light induced photoluminescence with fast decay times. Photoluminescence and X-ray excited optical luminescence (XEOL) properties and decay times were performed using a two-dimensional photon counting streak camera system with a time resolution up to 20 ps. The non-covalent interactions and supramolecular assemblies as a potential multiplier of the scintillating effect were investigated with the aid of a Hirshfeld surface analysis. The quality and phase purity of the used crystals and pellets was clarified by powder diffraction and Rietveld refinement. [ABSTRACT FROM AUTHOR]

We evaluated the photoluminescence (PL), scintillation, and dosimetric properties of Ce–doped Mg2SiO4 single crystals. As the PL and optically-stimulated luminescence (OSL) properties, the Ce–doped Mg2SiO4 showed the emission from 5d to 4f transitions of Ce3+. In the scintillation and thermally-stimulated luminescence (TSL) properties, two emission peaks due to Ce3+ and defect centers were observed. The Ce–doped Mg2SiO4 showed OSL by stimulating at 600 nm and TSL by heating at 50, 160, 195, and 370 °C. In OSL, linearly proportional responses were confirmed from 10 mGy for the 0.5 and 1% Ce–doped samples to 100 mGy for the 0.1% Ce–doped sample. In TSL, the undoped and Ce–doped samples had the linearity response from 100 to 0.01 mGy, respectively. [ABSTRACT FROM AUTHOR]

Dy3+-, Tb3+-activated, and Tb3+/Dy3+-coactivated oxyfluoride borogermanate scintillating glasses with the density of about 6.50 g/cm³ were successfully synthesized by a melt-quenching method. The structure and optical properties including transmittance, photoluminescence (excitation and emission spectra), photoluminescence decay, and X-ray excited luminescence (XEL) behaviors were studied in detail. Our results reveal that the energy transfer efficiency from Dy3+ to Tb3+ ions increases with an increase of Tb3+ concentration. The energy transfer mechanism is determined to be electric dipole–dipole interaction. However, the XEL intensity of Tb3+ decreases with the incorporation of sensitizer Dy3+ into borogermanate scintillating glass, which may result from the different mechanisms under ultraviolet light and X-ray excitation. [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]

The development and characterization of the optical properties of a neodymium(III)‐doped 42.75AlF3–33.25CaF2–19BaF2–5YF3 (Nd3+‐doped BCA‐5Y) glass in the vacuum ultraviolet (VUV) region are reported. Photoluminescence peaks at 180 and 227 nm are observed upon excitation with the 157 nm emission of a F2 laser. The dominant 180 nm emission peak is assigned to the 4f25d–4f3 (4I9/2 level) transition in Nd3+. This emission peak exhibits a fast, single exponential luminescence with a 16 ns decay time. The strong luminescence intensity and the fast decay time allude to its prospects for scintillator applications. [ABSTRACT FROM AUTHOR]

We successfully developed Eu-doped SrBr2 transparent ceramics with different Eu concentrations by spark plasma sintering and evaluated their optical and scintillation properties. As optical properties, the diffuse transmittance of the 0.01% Eu-doped sample was ~60% in the visible range. All the samples showed two absorption bands at around 250 and 350 nm, the origin of which was the 4f-5d (eg, t2g) transitions of Eu2+. Regarding scintillation spectra, the spectral shapes of all the Eu-doped SrBr2 transparent ceramics were similar to that of single crystals. In pulse height spectra, the photoabsorption peak of the 0.01 and 0.1% Eu-doped samples was confirmed, and the estimated light yields were 6600 and 13300 photons/MeV, respectively. Regarding afterglow properties, the afterglow levels of the 0.01 and 0.1% Eu-doped samples were comparable to that of a conventional Tl-doped CsI scintillator. [ABSTRACT FROM AUTHOR]

Unveiling the underlying mechanisms of properties of functional materials, including the luminescence differences among similar pyrochlores A2B2O7, opens new gateways to select proper hosts for various optoelectronic applications by scientists and engineers. For example, although La2Zr2O7 (LZO) and La2Hf2O7 (LHO) pyrochlores have similar chemical compositional and crystallographic structural features, they demonstrate different luminescence properties both before and after doped with Eu3+ ions. Based on our earlier work, LHO‐based nanophosphors display higher photo‐ and radioluminescence intensity, higher quantum efficiency, and longer excited state lifetime compared to LZO‐based nanophosphors. Moreover, under electronic O2−→Zr4+/Hf4+ transition excitation at 306 nm, undoped LHO nanoparticles (NPs) have only violet blue emission, whereas LZO NPs show violet blue and red emissions. In this study, we have combined experimental and density functional theory (DFT) based theoretical calculation to explain the observed results. First, we calculated the density of state (DOS) based on DFT and studied the energetics of ionized oxygen vacancies in the band gaps of LZO and LHO theoretically, which explain their underlying luminescence difference. For Eu3+‐doped NPs, we performed emission intensity and lifetime calculations and found that the LHOE NPs have higher host to dopant energy transfer efficiency than the LZOE NPs (59.3% vs 24.6%), which accounts for the optical performance superiority of the former over the latter. Moreover, by corroborating our experimental data with the DFT calculations, we suggest that the Eu3+ doping states in LHO present at exact energy position (both in majority and minority spin components) where oxygen defect states are located unlike those in LZO. Lastly, both the NPs show negligible photobleaching highlighting their potential for bioimaging applications. This current report provides a deeper understanding of the advantages of LHO over LZO as an advanced host for phosphors, scintillators, and fluoroimmunoassays. [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]

In this paper, we investigate the temperature dependence of luminescence characteristics of highly efficient cerium-doped scintillator, lutetium-yttrium orthosilicate Lu2(1-x)Y2xSiO5:Ce3+. The photoluminescence excitation and emission spectra have been measured in a broad temperature range. The temperature dependence of the Ce1 and Ce2 decay times shows the onset of decay time decrease at about 300 K. This observation demonstrates that unlike so far reported, the Ce2 center is not substantially quenched until room temperature. The 5d1 excited-state ionization of both Ce1 and Ce2 centers is studied by purely optical methods. [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]

Yb[sup 3+]-doped YAlO[sub 3] single crystals have been grown by the Czochralski method with a radio-frequency heating system. Starting melt compositions of Y[sub 1-x]Yb[sub x]AlO[sub 3] were varied with x=0.02, 0.1, 0.2, 0.3, and 0.45. The best Yb[sup 3+]-doped YAlO[sub 3] single crystals were obtained for a growth rate of 1.0 mm/h. The grown crystals were transparent and almost colorless. To investigate the homogeneity, the effective segregation coefficient of the Yb ion was estimated. The absorption, photoluminescence, and luminescence decay kinetics of Yb[sup 3+]-doped YAlO[sub 3] were investigated for the temperature range 4–300 K. Very fast charge transfer luminescence of Yb[sup 3+] from the near ultraviolet to visible spectral range and the high density of the Yb-rich YAlO[sub 3] makes this material a promising candidate for fast scintillators. © 2004 American Institute of Physics. [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]

Eu-doped CaAl2O4 bulk crystals were synthesized by the floating zone (FZ) method, and their photoluminescence (PL) and scintillation properties were investigated firstly in a bulk crystal. The crystal samples exhibit PL and radioluminescence (RL) with a broad emission peaking around 440 nm as well as sharp peaks appearing around 600 nm, which are similarly observed for powder samples. Suggested from the decay time constants, they are attributed to the 5d-4f transitions of Eu2+ and the 4f-4f transitions of Eu3+, respectively. From the pulse height spectrum under 241Am γ-ray (59.5 keV) exposure, the light yield (LY) of a 3.0% Eu:CaAl2O4 bulk crystal is approximately 12000 ph/MeV. [ABSTRACT FROM AUTHOR]

Novel Tb3+‐activated borogermanate‐tellurite scintillating glasses with a maximum density of 7.15 g/cm3 aimed at detection of high‐energy rays were prepared by a melt‐quenching method for the first time. The concentration‐dependent optical properties including transmittance, photoluminescence, luminescence dynamic behaviors, and X‐ray excited luminescence in the as‐prepared Tb3+‐activated borogermanate‐tellurite glasses were studied. The optimal content of Tb2O3 in the superdense borogermanate‐tellurite glasses is revealed to be 7 mol% under both 275 nm ultraviolet light and X‐ray excitation. The integral scintillation efficiency of Tb3+‐activated borogermanate‐tellurite scintillating glass is about 33.71% of the standard Bi4Ge3O12 (BGO) scintillating crystal. [ABSTRACT FROM AUTHOR]