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Pure and Eu2+‐activated fluoroborate BaGaBO3F2 was prepared using high‐temperature solid‐state reaction. BaGaBO3F2 is a wide band semiconductor with the indirect transition characteristic. The excitation and luminescence spectra of the phosphor were measured, and it was found that Eu2+‐activated BaGaBO3F2 exhibits a bright blue color under ultraviolet (UV) light. The narrow emission band peaked at 425 nm is attributed to the transitions of 4f65d→4f7(8S7/2), and the Stokes shift estimated for this phosphor sample is 3140 cm−1. The lifetime of the luminescence is also reported. The absolute quantum efficiency (QE) of the phosphor was evaluated, and it was found that the absolute QE decreases with increasing Eu2+ concentration. The phosphor shows an excellent quantum efficiency of 72.5% and a high thermal activation energy of 0.342 eV. The study concludes that Eu2+‐doped BaGaBO3F2 phosphor has promising luminescence application abilities and can be used as a blue‐emitting phosphor in a variety of applications. [ABSTRACT FROM AUTHOR]

Low‐dimensional copper‐based halide single crystals are considered excellent scintillators for indirect X‐ray detection, but their potential in direct X‐ray detection has not been investigated. Herein, high‐quality pure Cs3Cu2I5 and Li‐doped Cs3Cu2I5:Li single crystals are grown by the Bridgman method. The Li+ dopant enhances the photoelectric properties of the Cs3Cu2I5 single crystal by extending the carrier lifetime, improving the carrier mobility from 6.49 to 9.52 cm2 V−1 s−1, and increasing the mobility‐lifetime (µτ) product from 1.4 × 10−4 to 2.9 × 10−4 cm2 V−1. The sensitive direct X‐ray detector with a vertical device configuration of Au/Cs3Cu2I5:Li single crystal/PCBM/Au is fabricated and demonstrated to have a high sensitivity of 831.1 µC Gyair−1 cm−2 and low detection limit of 34.8 nGyair s−1. Furthermore, the detector shows negligible baseline current drift and excellent stability upon X‐ray radiation. [ABSTRACT FROM AUTHOR]

With the improvement of the conversion efficiency of LED chip and fluorescent material and the increasing demand for high-brightness light sources, LED technology has begun to move toward the direction of high-power. However, there is a huge problem that high-power LED must face with a large amount of heat generated by high power causing a high temperature thermal decay or even thermal quenching of the fluorescent material in the device, resulting in a reduction of the luminous efficiency, color coordinates, color rendering index, light uniformity, and service life of LED. In order to solve this problem, fluorescent materials with high thermal stability and better heat dissipation were prepared to enhance their performance in high-power LED environments. A variety of boron nitride nanomaterials were prepared by the solid phase-gas phase method. By adjusting the ratio of boric acid to urea in the raw material, different BN nanoparticles and nanosheets were obtained. Moreover, the control of catalyst amount and synthesis temperature can be used to synthesize boron nitride nanotubes with various morphologies. By adding different morphologies and quantities of BN material in PiG (phosphor in glass), the mechanical strength, heat dissipation, and luminescent properties of the sheet can be effectively controlled. PiG prepared by adding the right number of nanotubes and nanosheets has higher quantum efficiency and better heat dissipation after being excited by high power LED. [ABSTRACT FROM AUTHOR]

Halide perovskites are among the most attractive research hotspots in optoelectronic applications due to their excellent luminescence properties. In this paper, Li+ was successfully incorporated into a one-dimensional perovskite CsCu2I3 host and constructed as a novel neutron/gamma detection scintillator via the Bridgman method. XRD and ICP-MS were carried out, and the results were discussed. The Li-doped CsCu2I3 crystal exhibits a main emission peak at 575 nm originating from strongly localized 1D exciton emission and a high photoluminescence quantum efficiency of 18.7%. The CsCu2I3:Li crystal has a light yield of 10 900 photons per MeV and an energy resolution of 11.5% under 137Cs irradiation. The figure-of-merit (FoM) of the CsCu2I3:Li crystal has been estimated (about 0.8) under 252Cf radiation source. The crystal has a potential application for dual gamma–neutron detection. [ABSTRACT FROM AUTHOR]

A series of blue phosphors based on Eu2+-activated boracite Zn 3 B 7 O 13 Cl were synthesized by high-temperature solid-state reaction. The phase composition and crystal structure were confirmed by XRD Rietveld refinements, while the optical transitions and band natures were analyzed using absorption spectra. The blue luminescence of Zn 3 B 7 O 13 Cl:Eu2+ shows a narrow band spectrum peaked at 405 nm due to the 4f65 d→4f7(8S 7/2) transitions. Additionally, the sharp line transition of 4f7 (6P 7/2)→4f7 (8S 7/2) was also detected even at 300 K. The experiments confirm that the blue luminescence efficiency of Zn 3 B 7 O 13 (Cl 1-x F x):0.03Eu2+ (x = 0, 0.05, 0.1, 0.2, 0.3) is improved with the increase of the substitution of F− for Cl−. To further improve the luminescence efficiency, the samples were post-annealed at 850 °C in a reducing atmosphere. The results demonstrate that the post-annealing can improve the luminescence efficiency and thermal stability in as-prepared Zn 3 B 7 O 13 (Cl 1-x F x):0.03Eu2+ (x = 0, 0.05, 0.1, 0.2, 0.3) by eliminating the residual Eu3+. The maximum efficiency and thermal activation energy were confirmed in post-annealed Zn 3 B 7 O 13 (Cl 1-x F x):0.03Eu2+ (x = 0.3), which are 65% and 0.31 eV, respectively. The luminescence mechanisms and thermal stability of Eu2+ activators were discussed. • Zn 3 B 7 O 13 Cl:Eu2+ shows an efficient narrowband blue luminescence. • Sharp line transition of 4f7 (6P 7/2).→4f7 (8S 7/2) was also detected even at 300 K. • Luminescence efficiency increases with the substitution of F− for Cl− in the lattice. • Post-annealing eliminates residual Eu3+ resulting in significant improvement of luminescence. [ABSTRACT FROM AUTHOR]

Cs3Cu2I5 Single Crystal for Efficient Direct X‐Ray Detection In article number 2300247, Laishun Qin, Hongsheng Shi, Yanliang Liu, Xue‐Feng Yu, and colleagues demonstrate a high‐quality Li‐doped Cs3Cu2I5 single crystal grown by the Bridgman method that was initially applied as a semiconductor for direct X‐ray detection. The Cs3Cu2I5:Li X‐ray detector exhibits a high sensitivity of 831.1 µC Gyair−1 cm−2 and low detection limit of 34.8 nGyair s−1, and it reveals a clear outline of the key image in the scanning mode under X‐ray excitation. [ABSTRACT FROM AUTHOR]

Keywords: copper-based halides; Cs3Cu2I5:Li single crystal; direct X-ray detection; semiconductors EN copper-based halides Cs3Cu2I5:Li single crystal direct X-ray detection semiconductors 1 1 1 10/06/23 20231001 NES 231001 B Cs SB 3 sb Cu SB 2 sb I SB 5 sb Single Crystal for Efficient Direct X-Ray Detection b In article number 2300247, Laishun Qin, Hongsheng Shi, Yanliang Liu, Xue-Feng Yu, and colleagues demonstrate a high-quality Li-doped Cs SB 3 sb Cu SB 2 sb I SB 5 sb single crystal grown by the Bridgman method that was initially applied as a semiconductor for direct X-ray detection. Copper-based halides, Cs3Cu2I5:Li single crystal, direct X-ray detection, semiconductors The Cs SB 3 sb Cu SB 2 sb I SB 5 sb :Li X-ray detector exhibits a high sensitivity of 831.1 µC Gy SB air sb SP -1 sp cm SP -2 sp and low detection limit of 34.8 nGy SB air sb s SP -1 sp , and it reveals a clear outline of the key image in the scanning mode under X-ray excitation. [Extracted from the article]

In this work, Cs 2 LiLaBr 6 :1%Ce (CLLB:Ce) single crystal with the size of Ф26 mm × 80 mm were successfully grown by the Bridgman method. The optimal conditions of application were presented by coupling with R6231-100 PMT. The pulse spectra are recorded by the 4-channel digital converter DT5751 at a sampling rate of 1 GS/s. The energy spectra of the CLLB:Ce crystal were recorded under different PMT gain voltage. The best energy resolution is obtained (up to 3.8%) when the gain voltage of PMT is 3.65V. The non-proportionality of CLLB:Ce crystal was measured under varied radioactive sources while the background radioactive was discussed. Besides, the energy spectra of CLLB:Ce crystal were recorded when the temperature was varied from −30 °C to 50 °C. Finally, the discriminating ability of neutron and gamma was evaluated under 252Cf source and AmBe source, the FOM value is 1.4 and 1.2, respectively, which has a greatly potential application in the nuclear radiation detection. • Cs 2 LiLaBr 6 :1%Ce single crystal with the size of Ф26mm × 50 mm were successfully grown. • Cs 2 LiLaBr 6 :1%Ce has a good non-proportionality (3%). • CLLB:Ce crystal has a best scintillation properties at the temperature of 30 °C. • The FOM value of CLLB:Ce crystal is estimated about 1.4 under 252Cf source. [ABSTRACT FROM AUTHOR]

Ce3+/Tb3+ co-doped BaGaBO 3 F 2 is a new rare-earth activated luminescent material with efficient green luminescence. The phosphor was synthesized via the conventional solid-state reaction and characterized by X-ray powder diffraction, photoluminescence, and decay lifetimes. The Ce3+/Tb3+ co-doped phosphor exhibits an efficient excitation between 280 and 420 nm, making it suitable for commercial near-UV chips. The 4f–5d transitions of Ce3+ sensitizer allow the phosphor to be excited by the near-UV light, resulting in green and blue luminescence from Tb3+ and Ce3+, respectively. By controlling Ce3+/Tb3+ doping, the luminescence color can be tuned from blue to green. The effective transfer of excitation energy from Ce3+ to Tb3+ of BaGaBO 3 F 2 was confirmed by the spectral characteristics and decay lifetimes of samples with different doping concentrations. The dipole-quadrupole mechanism is responsible for the efficient energy transfer from Ce3+ to Tb3+, with a critical distance of 11.69 Å. These results demonstrate that Ce3+/Tb3+ co-doped BaGaBO 3 F 2 is an efficient near-ultraviolet (NUV) excitation phosphor with tunable luminescence from blue to green. This material has the potential to be used as a down-conversion phosphor for NUV light-emitting diodes. • Ce3+/Tb3+ co-doped BaGaBO 3 F 2 is a new rare-earth activated material. • Ce3+ acts as a sensitizer to efficiently transfer excitation to activators. • Luminescence color can be tuned from blue to green in BaGaBO 3 F 2 :Ce3+/Tb3+. • It is potential as a down-conversion phosphor for NUV LEDs. [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]

A series of Mn2+ single‐doped 0.2Gd2O3‐0.2Al2O3‐0.6SiO2 (GAS: xMn2+) glasses with Si3N4 as reducing agent were prepared. The presence of [SiO4‐x] defects and Mn2+ ions was determined from the absorption and excitation spectra of the glasses. With the increase of Mn2+ concentration, the intensity of blue emission decreases, while the intensity of red emission increases. The color coordinate of GAS: 6Mn2+ glass is (0.264, 0.226). The lifetime of the glasses was tested. Under the monitoring of 440 nm, the fast components (τf) are between 17 and 85 μs, and the slow components (τs) are between 200–650 μs. The former belongs to [SiO4‐x] defects, and the latter is [4E(G), 4A1(G)]→6A1(S) transition of Mn2+ ions. Under the monitoring at 630 nm, the τf are between 110 and 300 μs, and the τs are between 680 and 1220 μs, which are due to 4T1(G)→6A1(S) transition of Mn2+ ions and Mn2+ pairs, respectively. The energy transfer mechanism of [SiO4‐x] defect→Mn2+ ions are explained. The efficient [SiO4‐x] defect →Mn2+ ions energy transfer process was demonstrated by time‐resolved photoluminescence, and the energy transfer efficiency is over 85%. The maximum photoluminescence quantum yield (PL QY) of the glasses can reach 15.87%. The thermal activation energy of the glasses was calculated. In addition, X‐ray excited red luminescence spectra and the mechanism of the glasses were investigated. [ABSTRACT FROM AUTHOR]

(Gd,La) 9.33 (SiO 4 ) 6 O 2 :Ce polycrystalline powder with different proportion of Gd/La and Ce concentration was prepared by sol-gel technique, the crystal structure was confirmed by XRD, the luminescence properties were discussed under UV excitation. The energy transfer of Gd-Gd and Gd-Ce have been systematically investigated using luminescence spectra and there are three different types transfer mechanism for different Ce 3+ and La 3+ concentrations. The nonradiative energy transfer mechanism can switch from a short-range exchange mechanism to a longer-range dipole–dipole mechanism through energy migration between donors in heavily La substituted samples. The luminescence thermo-stability and activation energy were also measured and calculated. The luminescence properties and thermo-stability of Gd 9.33 (SiO 4 ) 6 O 2 :Ce polycrystalline were improved, because of La 3+ substitution which lead to the change of the energy transfer mechanism from Gd 3+ to Ce 3+ [ABSTRACT FROM AUTHOR]

• A serial of Ce3+-doped CLLBC single crystals were successfully grown. • Two different lattice positions of Ce3+ in the CLLBC crystal were proposed. • The scintillation properties depend on the structure and the concentration of Ce3+. • Energy resolution of 3.70 %(FWHM) at 662 keV was measured. In this work, a strategy of controlling the doping concentration of cerium is adopted to improve the gamma response performance of cutting-edge Cs 2 LiLa(Br,Cl) 6 :Ce (CLLBC:Ce) single crystal scintillators. A serial of Ce3+-doped Cs 2 LiLaBr 5.4 Cl 0.6 single crystals with a size of Ф12 mm × 50 mm were successfully grown by the Bridgman method. Two different lattice positions of Ce3+ in the CLLBC crystal were identified by using spectral and decay kinetics, Raman spectra, X-ray photoelectron spectroscopy, refined XRD. The effects of cerium substitution amount on local structure, crystal structure, luminescence properties and the scintillation properties were systematically investigated. As the Ce3+ content increased, the light yield and energy resolution of CLLBC:Ce were first improved and then deteriorated. The Cs 2 LiLaBr 5.4 Cl 0.6 :2 mol% Ce crystal has a highest light yield and optimal energy resolution of 3.70 % under 137Cs@662 keV excitation. [ABSTRACT FROM AUTHOR]

A novel NIR emitting scintillator with 825 nm was developed by doping Sm2+ in Cs 4 Eu(Br,I) 6 crystal. The single crystals of Cs 4 Eu(Br,I) 6 :Sm were successfully grown by the Bridgman method. The crystal structure and valence state was approved by XRD and XPS methods. The luminescence properties and energy transfer were systematically investigated. The energy transfer mechanism is variable for different Sm2+ concentration. The PL decay profiles show that the Sm2+-related emission has fast decay of nanosecond. The proportion of fast decay can be tunable by adjusting Sm2+ doped concentration. The Sm2+ doped europium -host material will have a potential application for unclear detection as near-infrared (NIR) scintillators. • The novel NIR emitting Cs 4 Eu(Br,I) 6 :Sm scintillation crystals were successfully grown by the Bridgman method and the luminescence properties is tunable. • The proportion of nonradiative energy transfer from Eu2+ to Sm2+ was improved and the PLQY of Sm2+-related is up to 42.1%. • The fast decay time component of Sm2+ (50 ns) is up to 31.8% for Cs 4 Eu(Br,I) 6 : 3 mol%Sm crystal. • The proposed Sm2+ doped europium -host material principle is an effective method to develop near-infrared (NIR) scintillators for nuclear radiation detection. [ABSTRACT FROM AUTHOR]

Bi4Si3O12\!\!:\!Zn^{2+}(BSO\!:\!Zn) polycrystalline powders were successfully prepared by sol-gel method. X-ray diffraction measurements confirm that the Zn^2+-doped materials are all monophasic solid solution powders. The influences of doping concentration on the photoluminescence and radioluminescence characteristics have been investigated and discussed. The Zn^2+ doped material shows a better light yield than that of undoped material under X-ray excitation. The fluorescence decay time of the optimal material, excited by UV has been aslso measured. The results show that the Zn^2+ ion doping has a positive effect on the light yield of BSO. But the crystal growth and characterizations of BSO:Zn polycrystalline powders prepared deserve further investigations. [ABSTRACT FROM PUBLISHER]

Abstract: A kind of direct white light phosphor Bi4Si3O12:Dy3+ (BSO:Dy3+) was successfully prepared through a sol–gel technique and its luminescence properties were investigated. The white-light emission is assigned to a mixture of three emission peaks located at 460nm, 488nm and 575nm, respectively. The possible process of origin phosphorescence has been discussed and PL spectra under different temperature conditions have also been recorded. The chromaticity color coordinates of BSO:Dy phosphors at different temperatures were calculated. The thermoluminescence curves exhibit two peaks at 400 and 440K in the range of 300–550K, corresponding to the electron traps with depths of 1.225 and 1.527eV individually. The BSO samples co-doped with Dy and Tb were also prepared and their luminescence properties were investigated. This work provides a promising approach for the development of white light phosphors. [Copyright &y& Elsevier]

Abstract: Ce-doped La2Si2O7 (LaPS:Ce) polycrystalline powders were successfully prepared through a sol–gel technique at lower temperature. The X-ray diffraction measurements confirmed that the Ce-doped powders were a kind of monophase solid solution. Photoluminescence, radioluminescence, and decay time characteristics of the prepared powders have been systematically investigated and discussed. It was noticed that the LaPS:Ce material shows an excellent light yield in comparison with commercial Y3Al5O12:Ce (YAG:Ce) powders under X-ray excitation. The LaPS:Ce sample demonstrated a high temperature stability of luminescence yield up to 250°C and a short decay time. Therefore, the LaPS:Ce powder is proposed to be a novel and promising scintillator material. [Copyright &y& Elsevier]

Near-infrared (NIR) emissive fluorophores with donor−acceptor−donor (D−A−D) structures are attractive for deep tissue in vivo bioimaging and sensing, owing to their low background autofluorescence and deep penetration depth. In this study, we constructed a series of nitric oxide (NO)-responsive fluorescent switches with D−A−D structure, in which functional heterocycles act as donor moiety, resulting in the modification of fluorescence wavelengths from NIR-I (750–950 nm) to NIR-II (1000–1700 nm) region. Specifically, the NIR-I fluorescence can be achieved by using furan, thiophene and selenophene as the donor moiety. By using pyrrole as the donor moiety, NIR-II fluorescence can be achieved due to the strong N–H⋯N hydrogen bond interaction and tunable intramolecular charge transfer (ICT) process. Based on our findings, tailoring electronegativity of donor moiety could controllably tune the fluorescence wavelength from NIR-I to NIR-II region, proposing a practical design strategy for developing NIR-II fluorescent switches. By modifying the hetero atoms of the heterocycle arms inducing to changing electrostatic potential, both DBT-X and BTT-X could achieve the red-shifted absorption and emission spectra, the fluorescence for NO detection could transform from NIR-I to NIR-II region. [Display omitted] • After reacting with NO, the formed product (BTT-X) enhanced the larger orbital overlap of localized excitations (LE) characters in bright hybridized local and charge transfer (HLCT) state than reactants (DBT-X). • By modifying the hetero atoms of the heterocycle arms inducing to changing electrostatic potential , both DBT-X and BTT-X could achieve the red-shifted absorption and emission spectra, the fluorescence for NO detection could transform from NIR-I to NIR-II region. • BTT-N exhibit the large Stokes shift of 778 nm and NIR-II fluorescence at the peak of 1202 nm, benefitting from strong N–H⋯N hydrogen bond interaction and tunable ICT process. [ABSTRACT FROM AUTHOR]

With the rapid development of silicon-based light detectors with high detection efficiency and long-wavelength sensitivity, the development of near-infrared scintillation crystals has become a hotspot. Especially, the Sm2+ doped europium-based halide crystals exhibit excellent near-infrared luminescence properties. In this paper, Cs4 EuI6: Sm near-infrared scintillation crystals with a size of cm-level were successfully prepared by Bridgman method. The composition and structure were discussed by XRD, XPS and ICP-OES methods, indicating that the Sm2+ was introduced and has no obvious effect on the crystal structure of the matrix. Under ultraviolet and X-ray excitation, the crystal has two luminescence centers (Eu2+ and Sm2+), and the emission peaks are located at 450 and 840 nm, respectively, corresponding to the 5d→4f luminescence of Eu2+ and Sm2+. The decay time of Eu2+ and Sm2+ is at the level of microsecond under ultraviolet excitation. The results show that the emission wavelength gradually varies from blue to near infrared as Sm2+ doping concentration increased. The effects of Sm2+ concentration on the luminescence properties, Eu2+ -Sm2+ energy transfer and decay time of the crystals were also studied, which means that the luminescence properties can be tuned by adjusting the Sm2+ doping concentration. [ABSTRACT FROM AUTHOR]

Abstract: The growth and scintillation properties of the Na2W2O7 crystal are reported. The solid reaction between Na2CO3 and WO3 is used to synthesise the Na2W2O7 material. The Na2W2O7 single crystal has been grown by the Bridgman method. And the Na2W2O7 single crystal with sizes 14×7×6mm3 has been achieved. The transmission spectra, the Ultraviolet fluorescence spectra and the X-ray excited luminescence spectra of the Na2W2O7 crystal are measured. The measurement results show that the Na2W2O7 crystal is a promising intrinsic scintillator. [Copyright &y& Elsevier]

Because of incongruent melting, phase separation occurs when Cs2LiLaBr6:Ce (CLLB:Ce) is grown from a melt using stoichiometric raw materials. In this study, raw materials with different amounts of excess LiBr are used to grow CLLB:Ce crystals. It is found that enough excess of LiBr is beneficial to the crystal growth of CLLB:Ce. A transparent 1 × 2‐in. CLLB:Ce single crystal is successfully grown by the vertical Bridgman method. The differential scanning calorimeter‐thermogravimetric analysis (DSC‐TG), X‐ray diffraction, and inductively coupled plasma mass spectrometry results are used to understand the crystallization behavior at different stages of the crystal growth process. The luminescence and related scintillation properties of the CLLB:Ce single crystal are investigated. The relative light output of the CLLB:Ce single crystal is about 48 000 ph MeV−1, which is 80% that of the LaBr3:Ce crystal. The energy resolution of the CLLB:Ce single crystal is 4.0% at 137Cs 662 keV. [ABSTRACT FROM AUTHOR]

CsPbI3 quantum dots (QDs) hold tremendous promise for quantum emitters, but they undergo a considerable energy loss when excited above their optical bandgap, which impedes the utilization of high‐energy photons. Different surface modification strategies have been proposed to improve the phase stability of CsPbI3 QDs, however, little progress has been made to realize high photoluminescence quantum yield (PLQY) with high‐energy photon excitation. Here, a non‐resonant barrier excitation (NRBE) mechanism in conjugated aromatic tetraphenylporphyrin (H2TPP)‐modified CsPbI3 QDs is presented, which enables a high PLQY in the high‐energy excitation regime as well as enhanced phase stability. Particularly, the proposed H2TPP ligand possesses adequate energy depth needed to realize NRBE in CsPbI3 QDs, which allows efficient charge injection from organic ligands to the inorganic core. As a result, the H2TPP‐modified CsPbI3 QDs exhibit enhanced light absorption, large Stokes shift, and near‐unity red emission when excited above the optical bandgap. The findings provide new insights into the ligand design strategies for improving optoelectronic properties. [ABSTRACT FROM AUTHOR]

Combinatorial chemistry is employed in the screening of white light emitting phosphors in the system Bi4-xSi3O12:Lnx (Ln: Pr3+, Eu3+, Tb3+, Dy3+, Er3+). [ABSTRACT FROM AUTHOR]

Different B 2 O 3 content was added to Ce3+–doped Gd 2 O 3 –Al 2 O 3 –SiO 2 (xBGAS:1.1Ce3+, x = 0, 5, 10, 15) glasses to improve the photoluminescence (PL) and scintillation properties. The transmittance of 15BGAS:1.1Ce3+ glass is over 80%. The X–ray absorption near edge spectroscopy (XANES) spectra imply that Ce4+ can be effectively reduced to Ce3+ in the glasses by adding Si 3 N 4. The excitation and emission spectra show a blue shift with increase of B 2 O 3 content. The photoluminescence quantum yield (PL QY) increases with the increase of B 2 O 3 content, reached the maximum of 59.55% when x = 15. The PL decay time of the glasses exhibits typical values (44–50 ns) due to 5d→4f transition of Ce3+ ions. The PL thermal activation energy become larger, indicating that xBGAS:1.1Ce3+ glasses have better luminescent thermal stability. The integral X–ray excited luminescence (XEL) intensity of the 15BGAS:1.1Ce3+ glass is 37.38% of Bi 4 Ge 3 O 12 (BGO) crystal, and the light yield is 1267 ph/MeV with an energy resolution of 23.22% at 662 keV when exposed to γ–rays. With the increase of B 2 O 3 content, the fast component of scintillation decay time gradually becomes shorter and the slow component becomes longer. The thermally stimulated luminescence (TSL) curves were measured to investigate the trap depth and density of defects in xBGAS:1.1Ce3+ glasses. [ABSTRACT FROM AUTHOR]

In this work, an anion-alloying strategy using chloride substitution is used to improve the gamma response performance of cutting-edge Cs 2 LiLaBr 6 :Ce single crystal scintillators. Single crystals of Cs 2 LiLa(Br , Cl) 6 :Ce (CLLBC:Ce) with a size of Ф12 mm × 50 mm were successfully grown by the Bridgman method. The effects of chloride substitution amount on crystal structure, band structure, luminescence properties and the scintillation properties were systematically investigated. The light yield and energy resolution of CLLB:Ce were enhanced as the increase of Cl− content. The highest light yield and optimal energy resolution were achieved on the Cs 2 LiLaBr 4 Cl 2 :Ce, about 86% of the commercial LaBr 3 :Ce single crystal and 4.1% at 662 keV. On a basis of the results of first-principle calculation and pure optical method, the band structures of Cs 2 LiLa(Br,Cl):Ce were constructed, indicating a tendency of band-gap to increase as the Cl− content increases. The origin of light yield improvement was also proposed. • The strategy of chloride substitution is used to improve the performance of Cs 2 LiLaBr 6 :Ce single crystal scintillators. • The results of first-principle calculation and pure optical method indicate that the band-gap becomes bigger as the Cl− content increases. • Cs 2 LiLaBr 4 Cl 2 :Ce shows the highest light yield and optimal energy resolution, about 86% of the commercial LaBr 3 :Ce single crystal and 4.1% at 662 keV. • The origin of light yield improvement was also proposed. [ABSTRACT FROM AUTHOR]

Luminescent Ag nanoclusters doped solid host, such as glass, are very promising new materials for lighting applications due to their good mechanical and optical properties. In the present work, transparent Ag nanoclusters doped oxyfluoride amorphous glasses, having starting composition of 30SiO 2 –70PbF 2 – x AgNO 3 ( x =0, 0.5, 3 mol%), were prepared using melt quenching technique. The Ag nanoclusters are spontaneously created during the casting of glass. The prepared Ag nanoclusters doped glasses emit green-yellow light under exposure to UV lamp ( λ ex =365 nm). The emission spectra of Ag nanoclusters doped glass show a red shift with the increase of excitation wavelength, and the excitation spectra show a similar red shift, that comes from Ag nanoclusters with different sizes and different local surroundings. The decay time of the Ag nanoclusters doped glass detected at the optimum wavelength ( λ ex =370 nm, λ em =530 nm) is only 2.1 ns, which may be attributed to the spin allowed singlet–singlet transitions of Ag 4 2+ tetramers. High temperature photoluminescence spectra of the glass ( x =3) show a slight decrease in luminescence intensity with the increase of temperature, and the luminescence intensity at 80 °C is about 60% of that at 25 °C. The Ag nanoclusters were effectively protected and stabilized by the 30SiO 2 –70PbF 2 glass host. [ABSTRACT FROM AUTHOR]

A hard template route has been successfully developed for synthesis of β-SiAlON:Eu phosphors at low temperatures. The synthesis utilizes mesoporous silica (SBA-15) skeleton as an active Si source, combined with the carbothermal reduction and nitridation method. It has been shown that the additional driving force from high surface area and porosity of SBA-15 enables β-SiAlON:Eu (with compositions of Si6-zAlz-xOz+xN8-z-x: xEu, x = 0.010-0.200 and z = 1.000) phosphors to be formed as a dominant phase at low temperature of 1400°C. The resultant β-SiAlON:Eu phosphor powders exhibit a typical rod-like morphology and a well dispersed state. By tailoring the Eu2+ concentration in the phosphors, a continuous change in emission band can be realized, that is a blue emission dominated for low Eu2+ concentrations and a green emission dominated for high Eu2+ doping concentrations. Furthermore, the resultant phosphors exhibit a small thermal quenching up to high temperature of 250°C. Therefore, the developed method is beneficial to synthesize LED phosphors of oxynitride systems at lower temperatures. [ABSTRACT FROM AUTHOR]

The photoluminescence and scintillation properties of Sn2+-doped gadolinium aluminum-silicate Gd 2 O 3 –Al 2 O 3 –SiO 2 (GAS) glasses with Si 3 N 4 as reducing agent were investigated. The glasses showed a wide emission band in the range of 360–730 nm due to the relaxation of S 1 –S 0 and T 1 -S 0 of Sn2+ luminescent centers. The luminescent intensity of Sn2+-doped GAS glasses reaches maximum at 0.3 mol% Sn2+. The lifetimes of the glasses vary between 6 and 12 μs, which related to the full width at half maximum (FWHM) of the emission spectra. Different oxides were added to explore the relationship between optical basicity and the luminescent properties of glasses. The addition of B 2 O 3 increases the photoluminescence quantum yield (PL QY) of the glasses, which is due to reduction of the Stokes shift and increment of radiative transition probability in energy level transition. The X-ray induced scintillation luminescence of the glasses were observed and studied. • The relationship between Stokes shift and optical basicity of the aluminum-silicate glasses. • High photoluminescence quantum yield (PL QY) in the Sn-doped glasses. • Quantitative analysis of the effect of phonon-electron interaction during Sn2+ luminescence. • The luminescence of Sn2+ centers excited by X-ray was observed for the first time in aluminum-silicate glasses. [ABSTRACT FROM AUTHOR]

Abstract: One kind of quaternary thin films of SiAlON were deposited by ion beam sputtering method at ambient temperature, through a sintered SiAlON ceramic target. Ultraviolet, visible and near infrared (UV–VIS–NIR) Spectrophotometer, Fourier transformed infrared spectroscopy (FTIR), glancing incidence X-ray diffraction (GIXRD) and X-ray photoelectron spectroscopy (XPS) were employed to characterize the optical, crystalline and chemical composition properties. The optical properties of the deposited amorphous films could be tailored by changing the relative content of O or N in the films, through introducing different working gas and gas flux adjusting (oxygen, nitrogen or their mixtures). By this way, the refractive index at 850 nm can be tailored from 1.53 to 1.83, and the chemical composition data from XPS analysis supplied strong evidences. Reasonably, the SiAlON films were thought to be one kind of candidate films either as a buffer layer benefit from their high temperature stability, or a mid infrared antireflective layer for silicon and other infrared window materials. [Copyright &y& Elsevier]

Abstract: Cerium-doped lutetium oxyorthosilicate (Lu2SiO5:Ce3+, or shortly LSO:Ce) luminescent ceramic fibers were synthesized by the sol–gel process followed with electrospinning in the present research. Polyvinyl butyral (PVB) was used as a spinnable carrier and anhydrous system availed the efficient generation of the composite fibers. The phase of Lu2SiO5 starts to appear at 1100°C based on XRD analysis. After annealed at 1200°C for 4h, all samples with different cerium doping concentrations show a pure phase of LSO with a well-crystallized structure. The annealed samples retain smooth surfaces and uniform morphologies. LSO:Ce fibers thus prepared exhibit a strong emission peak located at about 403nm, corresponding to the Ce3+ 5d1→4f1 transitions. LSO:1%Ce fibers exhibit the most intense emission among the samples doped with different cerium concentrations, which also present a much stronger emission than that of LSO:1%Ce powders. X-ray excited luminescence (XEL) spectrum shows that LSO:Ce fibers present a considerable scintillation property as well. Short decay time trait was also observed in LSO:Ce fibers due to their microscopic defects at grain boundaries and surfaces. [Copyright &y& Elsevier]

Semiconductor photocatalysis may be a promising strategy to face energy and environmental issues because it utilizes the solar energy as energy source. The artificially Z-scheme photocatalytic system has attracted special interests owing to its high efficiency and strong redox ability. Graphitic carbon nitride nanosheets (g-C3N4 NSs) display prominent performances, which are intensively investigated. Herein, we constructed an all-solid-state Z-scheme photocatalytic system and firstly immobilized g-C3N4 nanosheets on TiO2 nanotube arrays (TNTAs) by a simple method. The microstructures of prepared g-C3N4 NSs/TNTAs photocatalyst were characterized by XRD, X-ray photoelectron spectroscopy, SEM and TEM. The features of light absorption, charge separation, and charge transfer were analyzed by UV/Vis diffuse reflectance techniques, photoluminescence spectroscopy, electrochemical atomic force microscopy, and photocurrent measurement. The synthesized g-C3N4 NSs/TNTAs samples shows enhanced photocatalytic efficiency for rhodamine B degradation under visible light, which is four times more than that of pure TNTAs. Tetracycline hydrochloride could also be effectively degraded under visible light, which contributes to reducing antibiotic residues in wastewater. Additionally, g-C3N4 NSs/TNTAs also possess other advantages such as well long-term stability and easily recyclable properties. A reaction mechanism is also proposed. [ABSTRACT FROM AUTHOR]

β-SiAlON:Eu 2+ phosphors synthesis usually requires higher temperatures and higher nitrogen pressure conditions. In the present research, a low temperature technique has been developed to synthesize both β-SiAlON and Eu-doped β-SiAlON fibers by electrospinning combined with carbothermal reduction nitridation (CRN). The carbon sources used as reductant in CRN procedure have been optimized to effectively produce a well-crystallized β-SiAlON phase at lower temperatures of 1370–1500 °C. Additionally, through adding sucrose and covering activated carbon powders on the top of fiber precursor layers, the highly-pure β-SiAlON and β-SiAlON:Eu 2+ fibers could be obtained. The pyrolysis behavior of fiber precursors, crystalline phase, morphology, and UV excited luminescence properties of the produced ceramic fibers were also studied by using TG–DSC measurement, XRD analysis, SEM observation, and spectrometer method. The resultant fibers exhibit a smooth surface and an uniforme morphology with a substantial length. Moreover, the β-SiAlON:Eu 2+ fibers thus prepared show a blue light emission peaked at 470 nm under UV excitation. [ABSTRACT FROM AUTHOR]

Highlights: [•] Lu2Si2O7:Ce3+ micro-column structured films were fabricated by a chemical route. [•] The fabrication method combines Si nanowire arrays with dip-coating method. [•] Si nanowire arrays act as templates and provide Si sources in such a method. [•] Lu2Si2O7:Ce3+ films exhibit a columnar structure and a uniform morphology. [•] The films possess emission spectra peaking at 378nm and a fast decay time. [ABSTRACT FROM AUTHOR]

One-dimensional LuSiO:Ce (LPS:Ce) luminescent fibers were prepared by the sol-gel process combined with electrospinning with polyvinyl butyral as polymer in this study. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, thermogravimetric and differential scanning calorimetry, Fourier transform infrared spectroscopy, photoluminescence, and kinetic decays were used to characterize the resulting samples. After calcinated at 1200 °C, pure crystalline phase of LuSiO was obtained with well maintenance of the fiber morphology. The excitation and emission curves of LPS:Ce samples are influenced by cerium-doping concentrations. LPS:0.5%Ce fibers show the most intense emission among the samples. A fast decay time of tens of nanosecond was also observed in LPS:Ce fibers. Furthermore, LPS:0.5%Ce powders and Y co-doped LPS:0.5%Ce fibers were also prepared in a similar way for comparison. As a result, LPS:0.5%Ce fibers present a much stronger emission and higher quantum efficiency than that of LPS:0.5%Ce powders, and a close efficiency compared with YLuSiO:0.5%Ce fibers. In addition, a facile and efficient fiber molding process can be realized to assemble one-dimensional LPS:Ce fibers into three-dimensional (3D) fibers structures with different shapes like bracelet and spool. Such 3D fiber structures are dense enough and well-shaped even if after high temperature calcination. The high performance LPS:Ce fibers and LPS:Ce 3D fibers may have great potential applications for luminescent clad sensors, optoelectronic devices, or scintillating detectors [ABSTRACT FROM AUTHOR]

Orthorhombic (α) SSPbF 2 microcrystal was synthesized by a normal hydrothermal method. The influence of F/Pb ratio and hydrothermal reaction time on the crystal phase of the acquired PbF 2 samples were discussed, and a β to α phase transition was found according to the XRD results. The undoped α-PbF 2 powder showed a broad but weak emission band around 450–570 nm, which was due to (Pb 2 ) 3+ nearest neighbor pair centers. Dy 3+ ion doped α-PbF 2 samples showed main emission bands at 480 nm and 574 nm, which were assigned to the transitions from 4 F 9/2 to 6 H 15/2 and 6 H 13/2 of Dy 3+ , respectively. Furthermore, the morphology and crystalline properties of the undoped and Dy 3+ doped α-PbF 2 microcrystal powder were also discussed carefully. The decay time results combined with the X-ray excitation results suggested that Dy 3+ ion doped α-PbF 2 is a useful scintillating material for high energy physics applications, such as X-ray scintillating panel, etc. [ABSTRACT FROM AUTHOR]

Highlights: [•] New films of SiAlON were prepared by ion beam sputtering method. [•] SiAlON films show excellent antireflective effects for zinc sulfide window materials in infrared region of 3–5μm. [•] SiAlON films are mechanically hard enough to protect zinc sulfide window materials, such as high speed application. [ABSTRACT FROM AUTHOR]

The Cover shows a Z‐scheme g‐C3N4 nanosheets/TiO2 nanotube array photocatalyst. In their Full Paper, D. Zhou et al. successfully loaded graphitic carbon nitride nanosheets on the TiO2 nanotube arrays (TNTAs) by a facile immobilization method. The visible‐light‐driven Z‐scheme g‐C3N4 NSs/TNTAs photocatalyst has been prepared by simply dispersing g‐C3N4 NSs into the electrolyte during the in situ anodization. The colored dye Rhodamine B (Rh B) and colorless antibiotic agent tetracycline hydrochloride (TC‐HCl) can be effectively degraded on this photocatalyst under visible light irradiation. The all‐solid‐state Z‐scheme g‐C3N4 NSs/TNTAs displayed enhanced visible light photocatalytic activity and good stability. The paper may introduce new approaches in the design of highly efficient photocatalyst and brings new insight to environmental remediation. More information can be found in the Full Paper by D. Zhou et al. on page 3064 in Issue 19, 2016 (DOI: 10.1002/cctc.201600828). [ABSTRACT FROM AUTHOR]