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The zero-dimensional copper halide perovskite Cs 3 Cu 2 I 5 displays extraordinary luminescence and scintillation characteristics, and high-quality crystals are extremely desirable for exploring the commercial applications. Currently, the most critical issue in the solution growth of Cs 3 Cu 2 I 5 crystals is the easy oxidation of halides, which significantly hinders the optimization of crystal qualities. The hypophosphorous acid (H 3 PO 2) has been applied to inhibit the oxidation, nevertheless, the related mechanism is elusive and has been largely ignored. Herein, Cs 3 Cu 2 I 5 crystals have been grown from N, N-Dimethylformamide (DMF) solvent by the antisolvent vapor-assisted crystallization (AVC) method. It is verified that H 3 PO 2 effectively prevents the oxidation of Cs 3 Cu 2 I 5 by rapidly reducing Cu2+ and I 3 −, maintaining the stability of the precursor solution and continuously suppressing oxidation during the whole growth process. Meanwhile, by increasing the acidity of the solution, H 3 PO 2 dissolve precursor colloids and efficiently enhance the solubility of halides. Thus, the addition of H 3 PO 2 favors the rapid growth of centimeter-sized Cs 3 Cu 2 I 5 crystals with well-defined crystallographic planes within several days. As excellent gamma ray scintillator, the crystal exhibits high light yield of 38000 photons/MeV, with energy resolution of 5.6 % under 662 keV radiation from a 137Cs source. This work deeply elucidates new insight into the critical effect of H 3 PO 2 in the DMF based solution crystal growth, facilitating the preparation of large-size and high-performance copper halide perovskite crystals. [ABSTRACT FROM AUTHOR]

Ce‐doped Cs2LiLaBr6 (CLLB) scintillator crystals, known for their superior neutron/gamma dual‐mode detection capability and exceptional scintillation properties, have garnered significant attention for both fundamental science and practical applications. The role of Ce3+ cations as luminescent centers is pivotal, influencing the scintillation properties as their concentration varies. While the effects of Ce3+ concentration on scintillation performance are well‐documented, the ramifications for crystalline structure remain less explored. In this study, high‐quality CLLB:Ce single crystals are fabricated(atomic packing factor of maximum doped Ce is 0.04%) using the vertical Bridgman (VB) method and subsequently characterized their crystalline structure by neutron diffraction, X‐ray diffraction (XRD), and elemental analysis. The findings reveal a correlation between Ce3+ concentration and the crystal cell parameters, presenting intriguing deviations from Vegard's law. Such observations suggest the potential presence of alternative defects, potentially Li+ interstitials, in CLLB:Ce. This work offers critical insights for advancing the understanding and optimization of CLLB:Ce scintillators. [ABSTRACT FROM AUTHOR]

β-Ga2O3 is a well-known semiconductor material for power devices and other applications. Recently, β-Ga2O3 has also been reported as a scintillator material with a light yield of approximately 8400 ph./MeV, scintillation decay time of <1 μs, and density of 6.44 g/cm3. In this study, 45 cm diameter β-Ga2O3 single crystals were prepared via oxide crystal growth using the cold crucible (OCCC) method under various oxygen partial pressures. In the OCCC method, as in the cold crucible method, a high frequency is applied directly to the oxide materials, which are heated and melted, and the melt is held by the outermost solid material itself that is cooled by water using a copper hearth. In the OCCC method, crystal growth is performed while rotating the seed crystal, as in the Czochralski method, to increase the crystal diameter. The optical properties and radiation responses of the crystals grown under various oxygen partial pressures were evaluated. [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]

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]

The technology to grow single crystals of the required shape directly from a melt has been researched extensively and developed in various industries and research fields. In this study, a micro-pulling-down method and a Mo crucible were applied to the shape-controlled crystal growth of Y 3 Al 5 O 12 :Ce (YAG:Ce). Three types of Mo crucibles with different die shapes were developed. Stable crystal growth of more than 50 mm in length was achieved with the same shape as the die, and scintillation light output of ~20,000 ph/MeV, which is comparable with those of the YAG:Ce crystal grown by Cz method, were obtained. The transmittance of grown crystals above 500 nm was above 70%. The standard deviation (σ) of the scintillation light output at each position of the 50-mm-long sample was found to be within ±16%. [ABSTRACT FROM AUTHOR]

This study provided the first in-depth investigation of the effects of large dopant incompatibility (Pr3+ and La3+ ions) on the small host lattice element (Lu3+) in Lu 3 Al 5 O 12 (LuAG) single crystal. The growth of such complex crystals from the melt presented many challenges. By engineering the ionic radius ratio of RE- and M-site cations, a single-crystal phase stabilized by configurational entropy was achieved. This investigation elucidated the crystallization behavior of configurationally disordered rare-earth aluminum garnet oxide (Lu 1−x−y Pr x La y) 3 Al 5 O 12 from the melt and characterized its functional properties, including microstructural, optical, photoluminescence, and scintillation properties, between 5 and 300 K. Relaxation of the imposed strain energy led to local perturbations and destabilization of the garnet structure. Multielemental EDS mapping, micro-Raman spectroscopy, and thermoluminescence revealed the mechanism by which atomic size mismatch drove a smooth transition from the garnet to the perovskite phase in high entropy garnets. The optical, photoluminescence, and scintillation measurements provided fundamental insights into property changes driven by incompatibility doping. Standard and modified Judd-Ofelt theory analysis of absorption spectra determined the phenomenological Judd-Ofelt parameters Ω λ and radiative lifetimes. Atomic size mismatch engineering offers a promising approach to overcoming the limitations of conventional eutectic synthesis methods. • Perovskite inclusions, driven by atomic size mismatch, extend from rim to core. • Controlled incompatible La3+,Pr3+ codoping in LuAG modify functional properties. • Scintillation light yield improved up to 30% in La3+ codoped LuAG:Pr crystals. • (La,Pr)AlO 3 perovskite forms due to size mismatch of La3+ and Pr3+ with Lu3+. • Lattice disorder affects the intensity ratio of Pr³⁺ 5d→4 f and 4 f→4 f emissions. [ABSTRACT FROM AUTHOR]

Ce0.03Gd2.97Ga2Al3O12 (Ce:GGAG) single crystals were successfully grown by the traveling solvent floating zone method (TSFZ). A series of compositions, where the mole ratio is Gd2O3 : Al2O3 = 25 : 75, 27 : 73, 29 : 71, were investigated as solvents. The 25 mol% Gd2O3-75 mol% Al2O3 solvent component was found to be the most effective in stabilizing the molten zone to obtain a crystal rod with uniform diameter. The crystal cracks were relieved clearly due to the improved molten zone stabilization during the crystal growth process. XRD patterns of the obtained crystals prove the garnet structure without any evident second phase. The characteristic Ce3+ emission located at around 540 nm was presented in the photoluminescence and X-ray excited luminescence spectra. The scintillation light yield reaches up to 34 132 pho MeV−1 and scintillation decay time was optimized to 64 ns with a high fast decay component of about 85%. The TSFZ method demonstrated the growth feasibility of Ce:GGAG crystals that have an incongruent-melting trend with lower Ga/Al ratio in the compositions. [ABSTRACT FROM AUTHOR]

• (Gd 1-x Ce x) 3 (Ga 0.995 Cr 0.005) 5 O 12 single crystals were grown by micro-pulling down method. • The emission wavelengths of these crystals were approximately 730 nm. • Cr was segregated in the center part of the crystals. • The relationship between Cr segregation and emission intensity was investigated. • The correlation coefficients of thoes relationships were around 0.9. For the decommissioning of Fukushima Daiichi Nuclear Plants, a novel real-time dose-rate monitor consisting of a scintillator, 100-m long optical fiber and CCD spectrometer has been proposed, and this scintillation material is required to have an emission wavelength of longer than approximately 650 nm. In this paper, as a candidate material for the system, we focused on Ce/Cr co-doped Gd 3 Ga 5 O 12 (Ce/Cr:GGG) single crystals grown by the micro-pulling down method. Since the light output of this material was expected to depend on the Cr3+ concentration, we investigated the relationship between Cr segregation and luminescence properties in Ce/Cr:GGG crystal. Generally, a single photon counting method is not available to evaluate its light output accurately due to the long decay time, we used a novel technique "emission-intensity two-dimensional- mapping method" (2D-image method) to verify the light intensity at each point of the sample. This method realized estimation of the light intensity within the sample, though segregation of Cr3+ is observed. The results showed that Cr was concentrated in the center part along the radial direction in the grown crystals, while all parts had an emission wavelength of approximately 730 nm excited by X-ray. Using the 2D-image method, emission intensity was found to correspond to the Cr concentration, and its correlation coefficients between emission intensity and Cr concentration were over 0.8. We found that our material is available for the monitoring system when the Cr dense part of the crystal is cut and used. [ABSTRACT FROM AUTHOR]

• CaNb 2 O 6 , as a new intrinsic scintillator was firstly reported. • The influences of the growth atmosphere on the optical and scintillation properties were investigated. • Crystals grown in an O 2 atmosphere displayed higher quantum efficiency, X-ray luminescence intensity, light yield, and lower afterglow. Single crystal CaNb 2 O 6 was grown by the optical floating-zone method and characterized for a new intrinsic scintillator. Under Ar and O 2 growth atmospheres, the as-grown crystal rods (Ф 4–5 mm) exhibit a greyish and a colorless appearance, respectively, which are related with the oxygen vacancy. They both show a broad emission band with the maximum at 480 nm under UV excitation, while the one grown in O 2 is brighter with a photoluminescence quantum efficiency of 44%. Consequently, a 25% higher scintillation light yield was obtained in the crystals grown in O 2 compared to those in Ar. The other scintillation properties including radioluminescence spectrum, pulsed X-ray decay and afterglow were also characterized and compared. [ABSTRACT FROM AUTHOR]

• A serial of Eu2+-doped CLLB single crystals were successfully grown. • The Eu2+ activated CLLB matrix strategy increases the Stokes shift. • The light yields of CLLB: 2% Eu is 18700ph/MeV under 137Cs source at 662 keV. • CLLB: Eu crystal has the application potential of long afterglow X-ray imaging. In this work, a novel single crystal scintillator, Eu2+-doped Cs 2 LiLaBr 6 (CLLB: Eu) with Ф12 mm × 50 mm, was successfully grown by the Bridgman method. The effects of substitution amount of europium ions on the crystal structure, luminescent properties and scintillation properties were systematically studied by fluorescence spectroscopy, XEL, decay kinetics, and temperature-dependent emission spectra. The Cs 2 LiLaBr 6 :2%Eu sample presents the highest light yield under X-ray excitation, which is about 235 times that of commercial BGO single crystals. The nanosecond decay lifetime of Eu2+ was observed in Cs 2 LiLaBr 6 :Eu crystal. The afterglow result indicates that the Cs 2 LiLaBr 6 : Eu crystal has a long afterglow and the afterglow mechanism of Cs 2 LiLaBr 6 : Eu crystal was proposed and constructed. It has a potent application in nuclear radiation detection and imaging as a scintillation long afterglow material. [ABSTRACT FROM AUTHOR]

Yttrium-gadolinium pyrosilicate ((Y 2-x Gd x)Si 2 O 7) single crystals with different ratios of yttrium to gadolinium (x = 0.1–1.9) and 2% Ce-dopant were successfully synthesized using the floating-zone method. In this work, photoluminescence (PL) and scintillation properties of 2% Ce-doped (Y 2-x Gd x)Si 2 O 7 were investigated. The conducted experiments included PL decay time and emission, X-ray-induced decay time and scintillation spectra, an afterglow analysis, as well as the total scintillation light yield by γ-ray-irradiation pulse-height spectra. Interesting results were including the considerably low afterglow at 20 ms of 40–65 ppm compared to commercial scintillator materials on the market like CdWO 4. Further, the high light yield of 21,800 ph/MeV was achieved in Y 0.5 Gd 1.5 Si 2 O 7 under 662 keV (137Cs) γ-ray-irradiation. • 2% Ce-doped Yttrium-gadolinium pyrosilicate ((Y 2-x Gd x)Si 2 O 7 , x = 0.1–1.9) with were crystal growth by FZ-method. • PL and scintillation spectrum show emission at 350-420 nm From the Ce3+ 5d-4f transitions with The PL QY up to 73.1%. • PL and scintillation decay time constant result in 25–29 and 28–32 ns, respectively. • The samples afterglow level at 20 ms (Af 20) are 40–65 ppm. • Under 662 keV γ-ray, scintillation light yield of Ce doped YGPS is up to 21,800 ph/MeV for the Y 0.5 Gd 1.5 Si 2 O 7 sample. [ABSTRACT FROM AUTHOR]

• Impurity in raw materials/quartz crucible affects the quality of grown crystals. • Crucible designs play a crucial role for nucleation and further crystal growth. • High purity raw materials/fused quartz crucibles are vital for SrI 2 crystal growth. We report a systematic study on the growth of pure and Eu doped SrI 2 single crystals by Bridgman technique. The effect of various parameters pertaining to the impurity in raw material as well as in crucibles on the quality of the grown crystal has been experimentally checked and documented. Further we have also studied that nucleation behavior changes with selection of crucibles design. We have established that high purity raw material and OH free high pure fused quartz crucible enables the growth of good quality single crystal of pure SrI 2 and lower concentration of Eu doped SrI 2 without putting much effort in designing of crucible or furnace. For higher concentration of Eu doped SrI 2 single crystal growth, modification in crucible design is required to grow good quality single crystals. We believe that this work will guide young researchers struggling in growth of good quality single crystals of similar alkali halide scintillators. [ABSTRACT FROM AUTHOR]

Single crystal of Tm-doped LaCl 3 (LaCl 3 :Tm3+) with the dimension of diameter 7 mm and length 55 mm was successfully grown using an in-house-developed Bridgman furnace. The grown crystal has the self-trapped exciton (STE) emission in the range of 300–500 nm along with the characteristic emissions corresponding to the 4f-4f transition of Tm3+ ions under X-ray excitation. The scintillation characterizations of the grown crystal were performed by pulse height spectra, scintillation decay time, as well as pulse shape discrimination studies under γ-ray and α-particle excitation sources. The LaCl 3 :Tm3+ crystal was found to have a high light yield (42,000 ± 4,200 ph/MeV) with 4.2% energy resolution under γ-rays excitation. Moreover, the pulse shape discrimination was studied using 137Cs and 241Am as the radiation sources with a good FOM value. The results conclude the LaCl 3 :Tm3+ single crystal to be a promising candidate for X-ray and γ-ray detection purposes. • The LaCl 3 :Tm3+ crystal was successfully grown by Bridgman technique. • Host STE band and characteristic Tm3+ transition are visible in the XIL studies. • High light yield (41,511 ± 2,906 ph/MeV) with 4.23% energy resolution (137Cs source). • The timing performance of crystal was found to be 3.42 μs (89%) with 137Cs source. • The excellent PSD capability of LaCl 3 :Tm3+ crystal between γ-ray and α-particles. [ABSTRACT FROM AUTHOR]

A new tantalum silicate, Rb 4 Ta 2 Si 8 O 23 , was synthesized as high-quality single crystals by the high temperature flux growth method. Rb 4 Ta 2 Si 8 O 23 was found to exhibit intense blue luminescence and scintillation as a self-activated luminescent silicate. Rb 4 Ta 2 Si 8 O 23 crystallizes in the triclinic space group P 1 ‾ with lattice parameters of a = 6.8916(2) Å, b = 7.7669(2) Å, c = 11.0018(3) Å, α = 76.3110(10)°, β = 89.2560(10)°, and γ = 71.8090(10)°. The structure consists of corner-sharing SiO 4 tetrahedra forming infinite ribbons connected by isolated TaO 6 octahedra. The synthesis, structure, and optical properties are reported, notably, bright blue scintillation when exposed to X-rays. The scintillation of Rb 4 Ta 2 Si 8 O 23 was quantitatively evaluated by radioluminescence (RL) measurements and was determined to be ∼47% of BGO powder. [Display omitted] • Rb 4 Ta 2 Si 8 O 23 was synthesized using flux crystal growth. • The crystal structure was solved using single crystal X-ray diffraction. • Rb 4 Ta 2 Si 8 O 23 exhibits photoluminescence and scintillation. • Scintillation intensity was quantitatively determined to be 47% of BGO powder from RL measurements. [ABSTRACT FROM AUTHOR]

Organic scintillation crystals of the Diphenylacetylene (DPAC) and Diphenylacetylene (SDPAC) with 20 wt percent stilbene were successfully grown into single crystals by the temperature gradient method. The structural parameter of the grown single-crystal was confirmed by XRD which elucidates the grown crystal belongs to the monoclinic crystal system. The FTIR measurement confirmed expected vibrational modes corresponding to the functional group in grown crystals. TG/DTA analysis elucidates the thermal and chemical stability of SDPAC. The absorption wavelength and bandgap energy of grown crystals were measured by UV–visible spectral analysis. The pure and composite samples photonic emission spectrum was recorded by photoluminescence and found to have two significant emission peaks around 363 and 380 nm. The fluorescence decay time of the SDPAC crystal was found to be two decay exponential component of 15 ns for prompt and 61 ns for delayed component. The Vickers hardness measurement was assessed to demonstrate mechanical behavior of the crystal. [ABSTRACT FROM AUTHOR]

[Display omitted] • Gd 3 (Sc,Al,Ga) 5 O 12 :Ce single crystals were grown by micro-pulling-down method. • Crystals are considered phosphor converters for WLED and scintillators. • Decrease of garnet band gap and crystal field strength with increasing Sc3+ and Ga3+ content. • Small amount of secondary perovskite phase was evidenced by the photoluminescence. • Energy transfer from perovskite phase to garnet phase is observed. Luminescence, scintillation and photoconversion properties of Gd 3 Al 5−x−y Sc x Ga y O 12 :Ce crystals, grown by the micro-pulling-down method, were studied upon substitution of Al for Sc3+ and Ga3+ in the x = 1–2;y = 1–3 ranges. A decrease of the band gap and crystal field strength occurs in these garnets with increasing Sc3+ and Ga3+ content, resulted in blue-shift and reduced thermal stability of Ce3+ emission. Lowering of the scintillation light yield of crystals by two times and scintillation decay kinetic acceleration from 97 to 27 ns is observed at increasing Ga content in the y = 1–3 range. Sc and Ga admixing increases the number of deep charge traps, which additionally deteriorate of crystals scintillation performance. Application of Gd 3 Al 5−x−y Sc x Ga y O 12 :Ce crystals as phosphor converters of white LED was considered. Increasing the Sc3+ and Ga3+ content in crystals leads to linear blue shift of the converter emission and results in increasing the color temperature of LEDs from neutral to could white light. [ABSTRACT FROM AUTHOR]

Single crystal growth of novel dicesium molybdate (Cs 2 MoO 4) crystal by Czochralski technique was carried out. The single crystal phase was confirmed by powders X-ray diffraction analysis. The optical band gap of 4.22 eV was estimated from the absorbance spectra, measured at room temperature. The luminescence properties were measured under the excitation of 4.42 eV UV light from an LED source in the temperature range of 10–300 K. The photoluminescence light yield increases upon cooling down the grown crystal to 10 K. The luminescence decay time was analyzed with the sum of three exponential decay-time functions in the entire temperature range. The comparison of luminescence light yield with Li 2 MoO 4 (one of the promising scintillating bolometers for the neutrinoless double-beta decay search) at 10 K shows a similar light output. These preliminary investigations show that the grown crystal can be a good candidate crystal for the cryogenic dark matter and neutrinoless double-beta decay search. • The Cs 2 MoO 4 crystal has been grown by Czhochrlaski method for the 1st time. • Optical band gape of 4.22 eV was estimated from absorption spectrum. • A comparable luminescence yield with that of Li 2 MoO 4 crystal was obtained at 10 K. • The slow decay component was fitted with the three-level thermal quenching model. • This crystal has the potential to be used for the 0νββ decay search of 100Mo. [ABSTRACT FROM AUTHOR]

The Li 6 Y(BO 3) 3 :Pr3+, an alkali orthoborate compound have been synthesized as polycrystalline powders with different doping concentration of Pr3+ rare-earth as an activator. The transparent single crystal has also been grown in argon atmosphere by the Czochralski method with 1 mol. % of Pr3+ doping element. The grown crystal possesses a monoclinic structure with a space group of P 2 1 / c. The crystal has been cut and optically polished to study the luminescence properties with X-ray, UV, α-particles, and γ-ray excitations. The crystal has showed relaxed 4f15d-4f2 emission at 309 nm along with characteristic 4f2-4f2 transition emissions. The UV–Vis–NIR absorbance spectrum has been obtained in the range of 250–2000 nm. Above 300 nm the crystal has showed about 50% transmittance. The Commission International De I'Eclairage (CIE) chromaticity diagram is depicting the change in combined emission colors for different excitation positions. The scintillation properties of the crystal have been studied with γ-ray from 60Co, α-particles from 241Am and moderated thermal neutrons from a252Cf source. The pulse shape discrimination, obtained for γ-ray, α-particles, and moderated thermal neutrons has shown the potential of this scintillator for thermal neutron detection. • 1 mol% Pr3+ doped Li 6 Y(BO 3) 3 single crystal has been grown using Czochralski method. • 4f15d-4f2 transition luminescence has been observed in UV–Vis measurements. • UV–Vis–NIR absorbance has been studied for 3H 6 to 3P 2 , 3P 1 /1I 6 , 3P 0 , 1D 2 , 1G 4 , 3F 4 , 3F 3, and 3F 2 transitions. • CIE chromaticity 1931 diagram has been plotted for different UV excitations. • A good discrimination of thermal neutrons to γ-rays has been observed with pulse shape discrimination method. [ABSTRACT FROM AUTHOR]