Synthesis and luminescence properties of Tb3+/Eu3+ co-doped GdAlO3 phosphors with enhanced red emission

The(Gd_(0.97-x)Eu_xTb_(0.03))AIO_3(x= 0.005-0.07) phosphors were synthesized by the co-precipitation method,using ammonium bicarbonate as a precipitant.The combined technologies of FT-IR,XRD,FESEM,PLE/PL and photo luminescence decay analysis were used to study the phase evolution,morphologies and luminescent properties.The phosphors with good dispersion exhibit strong vivid red emission located at 617 nm(~5 D_0-~7 F_2 transition of Eu~(3+)) under the optimal excitation wavelength of 275 nm(~4 f~8-4 f~75 d~1 transition of Tb~(3+),~8 S_(7/2)→6~I_J transition of Gd~(3+)).The presence of Gd~(3+) and Tb~(3+) excitation bands on the PLE spectra monitoring the Eu~(3+) emission directly gives an evidence of Tb~(3+) → Eu~(3+) and Gd~(3+) → Eu~(~(3+)) energy transfer,The emission intensity varies with the Eu~(3+) amount,and the quenching concentration is ～5 at% which is close to the calculated value.The quenching mechanism is determined to be the exchange reaction between Eu~(3+).The temperature-dependent PL analysis indicates that the best(Gd_(0.92)Eu_(0.05)Tb_(0.03))AlO_3 sample possesses good thermally stable properties.All the(Gd_(0.97-x)Eu_xTb_(0.03))AIO_3 phosphors in this work have similar CIE chromaticity coordinates and color temperatures,which are(0.65 ± 0.02,0.35 ± 0.02) and ～2558 K,respectively.Fluorescence decay analysis shows that the lifetime for～617 nm emission decreases with the content of Eu~(3+) and temperature increasing.Owing to the Tb~(3+)→ Eu~(3+) energy transfer,the luminescent properties of the(Gd_(0.92)Eu_(0.05)Tb_(0.03))AlO_3 phosphors are superior to the single Eu~(~(3+)) doped sample(Gd_(0.95)Eu_(0.05))AlO_3.As a result,the prepared phosphors may be widely used in solid-state display and light emitting devices.     

Upconversion multicolor tuning of NaY(WO4)2:Tb3+ with Eu3+ doping

A series of Tb~(3+) and Eu~(3+) co-doped NaY(WO_4)_2 phosphors were synthesized by hydrothermal reactions.The crystal structure,morphology,upconversion luminescent properties,the energy transfer from Tb~(3+) to Eu~(3+)ions and the ~5 D_4→ ~7 F_5 transition of the Tb~(3+) ion in NaY(WO_4)_2:Tb~(3+),Eu~(3+) phosphors were investigated in details.The results indicate that all the synthesized samples are of pure tetragonal phase NaY(WO_4)2.Furthermore,the micrometer-sized needle spheres and excellent dispersion of the particles are obtained by adding polyethylene glycol(PEG-2000) as the surfactant.Phosphors of NaY(WO_4)_2:Tb~(3+),Eu~(3+) exhibit the492 nm blue emission peak,546 nm green emission peak,595 nm orange emission peak and 616 nm red emission peak under 790 nm excitation.The energy transfer from Tb~(3+) to Eu~(3+) is a resonant transfer,in which electric dipole-dipole interaction plays a leading role.By adjusting the doping concentration of Eu~(3+) in NaY(WO_4)_2: 1.0 mol%Tb~(3+),xmol%Eu~(3+) phosphors,the emitting color of UC phosphors can be tuned from green to red.     

Physicochemical properties of Li3Ba2La3(MoO4)8:Eu,Tb red-emitting phosphor for solid state white lamps

In this work,combustion synthesis was used for the first time to fabricate a phosphor material with red emission for applications in solid-state white-light lamps.We synthesized a material with emission wavelength at λ_em=617 nm,excited under long UV-blue wavelength based on Eu³⁺,Tb³⁺-activated molybdates Li₃Ba₂(La_1-x-yEu_xTb_y)₃(MoO₄)₈ with 0 ≤ x ≤1 and 0 ≤ y ≤ 1.A series of pow...     

A highly sensitive luminescent metal–organic framework thermometer for physiological temperature sensing

Thermal sensing and imaging in the physiological temperature range are of great importance for studying physiological processes and treating diseases. Metal-organic frameworks(MOFs) exhibit great promise for developing luminescent thermometers due to their remarkable structural diversities and tunable luminescence properties. Here, we synthesized a series of luminescent mixed-lanthanide MOFs,Eu_xTb_(1-x)BPT(x = 0.019, 0.058, 0.106; H3 BPT = biphenyl-3,4',5-tricarboxylate acid) and adopted powder X-ray diffraction(PXRD), thermogravimetric analysis(TGA) and Fourier transform infrared(FT-IR) to characterize the resulting products. The temperature-dependent photoluminescence emission spectra were recorded to investigate their potential applications in physiological temperature readout. It is found that the intensity ratio of Tb~(3+) to Eu~(3+) is linearly correlated with temperature and the relative sensitivity is higher than 1.5%/℃ over the entire physiological temperature range. Furthermore,the temperaturedependent luminescence color emission allows for visual colorimetric temperature measurements.Luminescence lifetime testing and triplet energy level measurement were further conducted to study the mechanism.     

Influence of reaction parameters on the luminescence properties of monodisperse NaGd(1−x−y)(WO4)2:xEu3+,yTb3+ phosphor by molten salt synthesis

Eu~(3+) activated and Eu~(3+), Tb~(3+) co-activated monodisperse sodium double tungstates NaGd(WO4)2 phosphors were prepared by molten salt method at 750 ℃ for 10 h using NaCl as a flux. The crystal structure and morphology of the as-synthesized phosphors were measured by XRD and SEM, respectively. The photoluminescence properties were characterized by PL spectra, decay lifetime and CIE. The presence of NaCl plays an important role in the morphology and luminescence properties. In this work,NaCl and one of the raw material Na_2 CO_3 in a certain proportion will form a low eutectic salt to decrease the reaction temperature and benefit the formation of monodisperse NaGd(WO_4)_2 crystals. The color of Eu~(3+) and Tb~(3+) co-doped NaGd(WO_4)_2 phosphors can be tuned from creamy white to orange, red and green by adjusting the doping concentration of rare earth ions, since the emission contain the broad blue-green emission origin from NaGd(WO_4)_2 host and characteristic red and green emission origin from Eu~(3+) and Tb~(3+) ions. The electroluminescent spectra and CIE measurement shows that the LED device with NaGd_((1-x))(WO_4)_2:xEu~(3+)(x = 0.24) phosphor can be excited by 365 nm and 380 nm LED chip, and their CIE coordinate is(x = 0.45, y = 0.45) and(x = 0.36, y = 0.37), Ra is 80.3 and 86.3, T_c is 3196 and4556 K, respectively. As a single-component phosphor, NaGd(WO_4)_2:Eu~(3+),Tb~(3+) have potential application in UV-pumped WLEDs.     

EXAFS study of cation reordering in NaYF4：Yb3＋,Tb3＋ up-conversion luminescence materials

The NaYF4：yb3＋,Tb3＋ （Xyb： 0.20, XTb： 0.04） materials were prepared using the co-precipitation method, lne as-preparea material was washed either with or without water in addition to ethanol and thereafter annealed for 5 h at 500℃. This resulted in materials with moderate or very high up-conversion luminescence intensity, respectively. The structural study carried out with X-ray powder diffraction revealed microstrains in the rare earth （R） sublattice that were relaxed for the material with very high up-conversion intensity thus decreasing energy losses. The local structural details were investigated with R LⅢ and Y K edge ex- tended X-ray absorption fine structure （EXAFS） using synchrotron radiation. Around 10 tool.% of the Yb3＋ ions were found to occupy the Na site in the material with very high up-conversion intensity. These Yb species formed clusters with the Tb3＋ ions occupying the regular Na/R sites. Such clustering enhanced the energy transfer between Yb3＋ and Tb3＋ thus intensifying the up-conversion emission.     

Energy transfer,superior thermal stability and multi-color emitting properties of langbeinite-type solid-solution phosphor K_2Dy_(1.5-x)Eu_xTa_(0.5)(PO_4)_3

Langbeinite type compounds are a large kind of oxometallate with good flexibility structure.Herein,we synthesized a new langbeinite type compound K_2 Dy_(1.5)Ta_(0.5)(PO_4)_3,in which the Dy~(3+) and Ta~(5+) were blended to occupy the same crystallographic sites.Simultaneously,solid solutions of K_2 Dy_(1.5)_(-x)Eu_xTa_(0.5)(PO_4)_3(x=0-1.5) were prepared and their photoluminescence properties were investigated.Due to energy transfer from Dy~(3+) to Eu~(3+),both Dy~(3+) and Eu~(3+) characteristic emissions are observed under 393 nm light excitation.The emitting color of K_2 Dy_(1.5-x)Eu_xTa_(0.5)(PO_4)_3 turns from green through yellow to red by simply adjusting the Eu~(3+) concentration from 0 to 0.4.Moreover,K_2 Dy_(1.48)Eu_(0.02)Ta_(0.5)(PO_4)_3 phosphor possesses excellent fluorescence thermal stability and exhibits zero thermal quenching at 150 ℃.These results manifest that K_2 Dy_(1.5-x)Eu_xTa_(0.5)(PO_4)_3 solutions are promising multi-color emitting phosphors candidate for near-UV LED.     

Multi-color luminescence in Eu3+/Tb3+ co-doped ZnAl amorphous materials and their annealed samples

Multi-color luminescence basing on amorphous Eu~(3+)/Tb~(3+) co-doped Zn-Al hydroxides and their annealed samples were studied in detail. Results suggest that excellent red emissions due to Eu~(3+) and green emissions attributed to Tb~(3+) appear under the excitation of favorable wavelength for all the asprepared amorphous samples. Moreover, the emission intensity depends on the Eu~(3+)/Tb~(3+) molar ratio. The samples annealed at 300, 500, and 700 ℃ still exhibit amorphous state,and multi-color luminescence kept in the samples annealed at 300 ℃, while luminescence quenched for the samples annealed at 500 and 700 ℃. However, a broad emission ranging from 450 to 650 nm occurs in some samples annealed at 900 ℃. Further, the fluorescence decay and lifetimes for the as-prepared samples and the samples annealed at 300 ℃ were investigated. It is found that all the decay curves of emissions due to Tb~(3+) and Eu~(3+) present characteristic double exponential function despite their different lifetimes.The present work may be a good example for developing new multi-color even white light emitting materials.     

Enhanced afterglow performance of CaAl_2O_4:Eu~(2+),Nd~(3+) phosphors by co-doping Gd~(3+)

In order to effectively improve the afterglow properties of CaAl_2 O_4:Eu~(2+),Nd~(3+) phosphors,a series of Ca_(0.982-x)Al_2 O_4:0.012 Eu~(2+),0.006 Nd~(3+),xGd~(3+)(x=0,0.012,0.024,0.036,0.048,0.060 mol) phosphors were prepared by a high-temperature solid-phase approach.Crystalline composition and microstructure were characterized by XRD,TEM,HRTEM,and XPS,luminescence properties were systematically analyzed by fluorescence spectra,afterglow decay curves and TL glow curve.Results show that all of Ca_(0.982-x)Al_2 O_4:0.012 Eu~(2+),0.006 Nd~(3+),xGd~(3+)phosphors belong to monoclinic CaAl_2 O_4,without other cystalline phase.The blue emission at 442 nm is observed,which is assigned to the 4 f~65 d→4 f~7 transition of Eu~(2+) ions.Doping with appropriate amount of Gd~(3+) ions(x=0.036 mol) significantly improves the afterglow properties of phosphors,but the excessive doping of Gd~(3+) induces the fluorescent quenching.The doping of moderate Gd3+changes the traps states,the trap depth varies from 0.598 to 0.644 eV and the trap concentration is also greatly improved,thus significantly improving afterglow performance.     

Structure and luminescence properties of color-tunable phosphor Sr2La3(SiO4)3F:Tb3+,Sm3+

A series of single-phase and color-tunable phosphors Sr₂La₃(SiO₄)₃F:0.15Tb³⁺,xSm³⁺(SLSOF:0.15Tb³⁺,xSm³⁺) was prepared using solid-state route.The X-ray diffraction(XRD) was used to characterize the phase of the as-prepared samples.The synthesized phosphors have apatite-type structure without other impurities.Sm³⁺ and Tb³⁺ ions substitute La³⁺ into the lattice and form a single...     

Synthesis,structural and optical properties of SrZrO3：Eu3＋phosphor

Eu3+ activated Sr1–xEuxZrO3(x=0.01–0.04) phosphor with perovskite structure was successfully synthesized by using combustion method.The structure,morphology and optical properties of the material were characterized by X-ray diffraction,scanning electron microscopy and fluorescence spectrometry.The XRD results indicated that crystals of SrZrO3:Eu3+ belongs to tetragonal perovskite system.The phosphor could be effectively excited by UV light and the emission spectra results indicated that reddish-orange luminescence of SrZrO3:Eu3+ due to magnetic dipole transition 5D0→7F1 at 593 nm was dominant.Thus,the prepared phosphor showed remarkable luminescent properties which find applications in field emission display(FED) and plasma display panel(PDP) devices.     

Red-emitting CaWO4:Eu3+,Tm3+ phosphor for solid-state lighting: Luminescent properties and morphology evolution

CaWO₄:xEu³⁺,yTm³⁺crystals were obtained by facile synthesis at low temperature by the microwaveassisted hydrothermal method(MAH).The phase formation,morphology,luminescent properties and ene rgy transfer were investigated.The X-ray diffraction(XRD)re sults show the formation of a scheelitelike tetragonal structure without the presence of secondary phases.The growth mechanism of hierarchical micro structures based on self-assembly and Ostwald-ripening processes was evaluated,obtaining different types of morphologies.The luminescence spectra of CaWO₄:Eu³⁺,Tm³⁺at 325 nm excitation show the predominance of red emission at the 5 D0→7 F2(Eu³⁺)transition at 624 nm.This feature signals dominant behavior of the electric dipole type.The presence of Tm³⁺is notably evident in the absorption spectra by the related excitation transitions:3 H6→1 G4,3 H6→3 F3 and 3 H6→3 H4.Color parameters are discussed to characterize CaWO₄:Eu³⁺,Tm³⁺emission.The study of the emission spectrum as a function of the concentration of Eu³⁺(x mol%)and Tm³⁺(y mol%)indicates that the CaWO₄:Eu³⁺,Tm³⁺phosphors show stronger red emission intensity and exhibit the CIE value of x=0.63 and y=0.35.The photoluminescence results show 97%high color purity for CaWO₄:4 mol%Eu³⁺,a high CRI(92%)and a low CCT of 1085 K.These results demonstrate that the CaWO₄:Eu³⁺,Tm³⁺red phosphors are promising as color converters for application in white light-emitting diodes and display devices.     

Synthesis and enhanced photoluminescence properties of red emitting divalent ion (Ca2+) doped Eu:Y2O3 nanophosphors for optoelectronic applications

This work presents the synthesis of Y₂O₃:Eu³⁺,xCa²⁺ (x = 0 mol%, 1 mol%, 3 mol%, 5 mol%, 7 mol%, 9 mol%, 11 mol%) nanophosphors with enhanced photoluminescence properties through a facile solution combustion method for optoelectronic, display, and lighting applications. The X-ray diffraction (XRD) patterns of the proposed nanophosphor reveal its structural properties and crystalline nature. The transmission electron microscope (TEM) results confirm the change in the shape of the particle and aggregation of particles after co-doping with Ca²⁺. Fourier transform infrared spectroscopy (FTIR) and Raman vibrations also confirm the presence of Y–O vibration and subsequently explain the crystalline nature, structural properties, and purity of the samples. All the synthesized nanophosphors samples emit intense red emission at 613 nm (⁵D₀→⁷F₂) under excitation with 235, 394 and 466 nm wavelengths of Eu³⁺ ions. The photoluminescence (PL) emission spectra excited with 235 nm illustrate the highest emission peak with two other emission peaks excited with 466 and 394 nm that is 1.4 times higher than 466 nm and 1.9 times enhanced by 394 nm wavelength, respectively. The emission intensity of Y₂O₃:Eu³⁺,xCa²⁺ (5 mol%) is increased 8-fold as compared to Eu:Y₂O₃. Doping with Ca²⁺ ions enhances the emission intensity of Eu:Y₂O₃ nanophosphors due to an increase in energy transfer in Ca²⁺→Eu³⁺ through asymmetry in the crystal field and by introduction of radiative defect centers through oxygen vacancies in the yttria matrix. It is also observed that the optical band gap and the lifetime of the ⁵D₀ level of Eu³⁺ ions in Y₂O₃:Eu³⁺,xCa²⁺ nanophosphor sample gets changed with a doping concentration of Ca²⁺ ions. Nanophosphor also reveals high thermal stability and quantum yield as estimating activation energy of 0.25 eV and 81%, respectively. CIE, CCT, and color purity values (>98%) show an improved red-emitting nanophosphor in the warm region of light, which makes this material superior with a specific potential application for UV-based white LEDs with security ink, display devices, and various other optoelectronics devices.     

Synthesis,crystal structure and photoluminescence properties of novel double perovskite La2CaSnO6:Eu3+ red-emitting phosphors

A series of new double perovskite La_2–xEu_xCaSnO₆ (0 ≤ x ≤ 0.8) red phosphors were synthesized by traditional solid-state reaction. The phase, microstructure, photoluminescence (PL) properties, quantum efficiency, and thermal stability of the phosphors were investigated. La₂CaSnO₆ matrix has a monoclinic double perovskite structure with space group P2₁/n. Under near-ultraviolet (UV) light at 395 nm, La_2–xEu_xCaSnO₆ phosphors exhibit the most typical red emission peak at 614 nm, which corresponds to ⁵D₀→⁷F₂ electric dipole transition of Eu³⁺. The optimum Eu³⁺ doping content is attained at x = 0.5, and the La_1.5Eu_0.5CaSnO₆ phosphor shows a moderate quantum efficiency (32.3%) and high color purity (92.2%). Besides, the temperature-dependent spectrum of the phosphor was studied. The emission intensity of Eu³⁺ at 423 K decreases to 70.94% of the initial intensity at 303 K, and the activation energy ΔE is estimated to be 0.232 eV, suggesting that the phosphors possess good thermal stability. The fabricated w-LED based on the phosphors has higher R_a (89), lower CCT (4539K), and better chromaticity coordinates (0.371, 0.428). These results prove that the Eu³⁺-doped La₂CaSnO₆ red phosphor has great potential applications in w-LEDs.     

Optical and luminescence characteristics of Eu3+-doped B2O3:SiO2:Y2O3:CaO glasses for visible red laser and scintillation material applications

Europium(Eu~(3+)) doped glasses of chemical compositions(55-x)B_2O_3:10 SiO_2:25 Y_2O_3:10CaO:xEu_2O_3,where x denotes mol% and ranges 0≤ x ≤ 2.5, were synthesized by adopting conventional melt quenching technique, Physical properties like density, molar volume, polaron radius, inter-ionic distance and field strength of the glass samples were investigated to assess the impact of Eu_2O_3. Optical and luminescence properties of the glasses were characterized with optical absorption, photoluminescence,X-ray induced emission spectra, temperature dependence emission spectra and decay times. Judd-Ofelt(JO) intensity parameters(Ω_λ) of the glasses were evaluated based on the absorption spectrum of 0.5 mol%. JO parameters, calculated from absorption spectra with thermal corrections on oscillator strength, were used to evaluate radiative properties such as radiative transition probability(A_R),branching ratio(β_R), stimulated cross section emission(σ) and radiative lifetime(τ_R) for ~5D_0→~7 F_J(J = 0,1,2,3 and 4) transitions. The decay rate of ~5D_0 fluorescent level for all the glass samples was single exponential. Lifetimes of the ~5D_0 level were decreased with increasing concentrations of Eu~(3+)ions from 0.05 mol% to 2.5 mol% which might be due to energy transfer through cross-relaxation in the glasses. The chromaticity coordinates(x, y) were similar for all BSYCaEu glasses and were located at the red region of CIE 1931 color chromaticity diagram. Hence, these results confirm that the Eu~(3+) doped BSYCaEu glasses could be useful for visible red lasers and glass scintillation applications.     

Synthesis,photoluminescence properties and thermal investigation by TG-MS of RE(DAS)_3·xH_2O(RE=Eu~(3+),Tb~(3+))

Rare earth(Ⅲ) diphenyl-4-amine sulfonates(RE(DAS)_3·xH_2O,RE=Eu~(3+),Tb~(3+))phosphors were synthesized by precursor method from barium diphenyl-4-amine sulfonate and rare earth sulfates.FTIR,TG/DSC coupled to mass spectrometry(TG/DSC/MS),X-ray powder diffraction(XPD),scanning electron microscopy(SEM) and photo luminesce nce(PL) spectroscopy were utilized to structurally and morphologically characterize the samples.Thermal decomposition of Eu(DAS)_3·7H_2O and Tb(DAS)_3·2H_2O at 973 K under dynamic air atmosphere results in crystalline Eu_2O_2SO_4 and Tb_2O_2SO_4 materials,respectively.Accordingly,MS spectra reveal the liberation of thermal decomposition products of precursors,largely as CO_2,NO_2 and SO_2 gases.The diphenyl-4-amine sulfonate(DAS) ligand demonstrats a good stabilizing property for Eu~(3+) and Tb~(3+) ions.The Eu(DAS)_3·7H_2O and Tb(DAS)_3·2H_2O compounds display efficient red and green emissions,under UV excitation,arising from the ~5D_0→~7F_J(J=0-4) and ~5D_4→~7F_J(J=0-6) transitions of the Eu~(3+) and Tb~(3+) ions,respectively.     

Influence of dysprosium concentration on sensitivity of luminescent thermometers of phosphors Ca_9Tb(PO_4)_5(SiO_4)F_2

Tb~(3+),Dy~(3+)-co-doped Ca_9 Tb_xDy_(1-x)(PO_4)_5(SiO_4)F_2 phosphors were prepared via high-temperature solidphase reaction method and the potential application in optical temperature measurements due to their color-tunable property was investigated in detail.The photoluminescence emission(PL) and photoluminescence excitation(PLE) spectra results show that the as-prepared phosphors exhibit both Tb~(3+) and Dy~(3+) emissions at 546 nm(~5 D_4-~7 F_5 transition of Tb~(3+)) and 587 nm(~4 F_(9/2)-~6 H_(13/2) transition of Dy~(3+)) upon376 nm excitation,respectively.In addition,the fluorescence decay analysis shows that the lifetime of the Tb3+emission rapidly decreases,which confirms the energy transfer existence between Dy~(3+) and Tb~(3+).Under 376 nm excitation,the temperature dependence of the fluorescence intensity ratios for the dualmission bands peaked at 546 and 587 nm was studied in the temperature range from 303 to 573 K.The results show that with the increase of Dy~(3+) concentration,the relative sensitivity first increases and then decreases,what's more,the maximum relative sensitivity is 3.142×10~(-3)%/K for Ca_9 Tb_xDy_(1-x)(PO_4)_5(SiO_4)-F_2(x=0.4).As a consequence,this preliminary study provides a novel method for exploring the novel thermo meters.     

Photoluminescent properties of Eu3＋ and Tb3＋ codoped Gd2O3 nanowires and bulk materials

In this paper, the Gd2O3：Eu3＋,Tb3＋phosphors with different doping concentrations of Eu3＋and Tb3＋ions were prepared by a hydrothermal method for nanocrystals and the solid-phase method for microcrystals. The interaction of the doped ions with different concentrations and the luminescent properties of the nanocrystals and microcrystals were studied systematically. Their structure and morphology of Gd2O3：Eu3＋,Tb3＋phosphors were analyzed by means of X-ray powder diffraction （XRD）, transmission electron mi-croscopy （TEM） and scanning electron microscopy （SEM）. The photoluminescence （PL） properties of Gd2O3：Eu3＋,Tb3＋phosphors were also systematically investigated. The results indicated that when the concentration of doped Eu3＋was fixed at 1 mol.%, the emis-sion intensity of Eu3＋ions was degenerating with Tb3＋content increasing, while when the Tb3＋content was fixed at 1 mol.%, the emission intensity of Tb3＋ions reached a maximum when the concentration of Eu3＋was 2 mol.%, implying that the energy transfer from Eu3＋to Tb3＋took place. In addition, Tb3＋could inspire blue-green light and the Eu3＋could inspire red light. Therefore co-doping systems by controlling the doping concentration and the hosts are the potential white emission materials.     

Effects of europium concentration on luminescent and scintillation performance of Cs0.2Rb0.8Ca1-xEuxBr3(0≤x≤0.08)crystals

A series of Cs_0.2Rb_0.8Ca_1-xEu_xBr₃(0≤x≤0.08)crystals doped with different concentrations of Eu²⁺were grown using the Bridgman-Stockbarger method.The work describes the influence of Eu²⁺concentration on the luminescent and kinetic properties of Cs_0.2Rb_0.8Ca_1-xEu_xBr₃ crystals,as well as on their scintillation performance.The maximum in the radioluminescence spectra of these crystals shifts from 439 to446 nm with increasing europium concentration.The scintillation decay times of Cs_0.2Rb_0.8Ca_1-xEu_xBr₃ lengthen with the Eu²⁺content.The best light output of 33600photons/MeV is obtained for Cs_0.2Rb_0.8Ca_0.93Eu_0.07Br₃,and the best energy resolution of 6.9%is found for Cs_0.2Rb_0.8Ca_0.94Eu_0.06Br₃.     

A single-phase full-color phosphor Sr2Ca2La(PO4)3O:Eu2+,Tb3+,Mn2+: Photoluminescence and energy transfer

A single-phase full-color emitting phosphor Sr₂Ca₂La(PO₄)₃O:Eu²⁺,Tb³⁺,Mn²⁺ was synthesized by the high temperature solid-state method. The phase formation, luminescence properties, thermal stability, and energy transfer from Eu²⁺ to Tb³⁺ and Eu²⁺ to Mn²⁺ in Sr₂Ca₂La(PO₄)₃O were investigated in details. Tunable emission color from blue to blueish green or orange can be observed under 365 nm near-ultraviolet excitation based on the energy transfer from Eu²⁺ to Tb³⁺ or Mn²⁺ ions by varying the ratio of Eu²⁺/Tb³⁺ or Eu²⁺/Mn²⁺ ions. White light was obtained with chromaticity coordinates of (0.3558, 0.3500) in the Sr₂Ca₂La(PO₄)₃O:0.04Eu²⁺,0.08Tb³⁺,0.40Mn²⁺ phosphor, suggesting their potential applications in white light emitting diodes.