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Tricolor- and White Light–Emitting Ce <sup>3+</sup> /Tb <sup>3+</sup> /Mn <sup>2+</sup> -Coactivated Li <sub/>2</sub> Ca <sub/>4</sub> Si <sub/>4</sub> O <sub/>13</sub> Phosphor via Energy Transfer
摘要： Single-component tunable Li2Ca4Si4O13:Ce3+,Tb3+,Mn2+ phosphors were successfully synthesized at 950 °C. Li2Ca4Si4O13:Ce3+,Tb3+ exhibits two luminescence peaking at 430 and 550 nm, which originated from the allowed 5d → 4f transition of the Ce3+ ion and the 5D4 → 7FJ (J = 6, 5, 4, 3) transition of the Tb3+ ion, respectively. Moreover, by codoping Ce3+ ions in the Li2Ca4Si4O13:Mn2+ system, yellow-red emission from the forbidden transition of Mn2+ could be enhanced. Under UV excitation, dual energy transfers (ETs), namely, Ce3+ → Mn2+ and Ce3+ → Tb3+, are present in the Li2Ca4Si4O13:Ce3+,Tb3+,Mn2+ system. The ET process was confirmed by the overlap of the excitation spectra, variations in the emission spectra, ET efficiency, and decay times of phosphors. In addition, quantum yields and CIE chromatic coordinates are presented. The emission color of these phosphors can be tuned precisely from blue to green via ET of Ce3+ → Tb3+ and from blue to yellow via ET of Ce3+ → Mn2+. White light can also be achieved upon excitation of UV light by properly tuning the relative composition of Tb3+/Mn2+. This result indicates that the developed phosphor may be regarded as a good tunable emitting phosphor for UV light-emitting diodes.
关键词： phosphor,energy transfer,Mn2+,Tb3+,Li2Ca4Si4O13,Ce3+,white light-emitting diodes
更新于2025-11-14 15:29:11
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Energy Transfer from Ce3+ to Tb3+ in Yttrium and Gadolinium Orthoborates Obtained by Hydrothermal Synthesis
摘要： We studied the structure, IR absorption spectra, the spectral characteristics of photoluminescence and morphology of cerium- and terbium-doped orthoborates of gadolinium and yttrium obtained by hydrothermal synthesis at 200°C, as well as solid solutions of orthoborates on the basis of yttrium, gadolinium, and lutetium with composition RECe0.01Tb0.1BO3 (RE = Lu0.5Gd0.39, Lu0.5Y0.39, and Y0.5Gd0.39). The X-ray diffraction spectrum of yttrium orthoborate Y1 – x – yCexTbyBO3 is described by a hexagonal lattice with space group P63/m, which, after annealing at 970°C, transforms into a monoclinic lattice with space group C2/c. High-temperature annealing of the studied orthoborates leads to a multiple, more than two orders of magnitude, increase in the luminescence intensity of Tb3+ ions when the samples are excited in the absorption band of cerium ions. This effect is the result of a significant increase in the concentration of Ce3+ ions in the orthoborates at high temperatures. It is shown that the luminescence of terbium ions is due to energy transfer from Ce3+ to Tb3+, which proceeds with high efficiency (～85%) by the mechanism of dipole-dipole interaction between cerium and terbium.
关键词： orthoborates,luminescence,Ce3+,hydrothermal synthesis,energy transfer,Tb3+
更新于2025-11-14 15:14:40
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The luminescent properties of GdAlO<SUB align="right">3:Tb<SUP align="right">3+</SUP> phosphors based on molten salts addition
摘要： The (Gd1–xTbx)AlO3 (x = 0–0.12) were obtained through ammonium bicarbonate co-precipitation technology. The pure-phase (Gd1–xTbx)AlO3 with good dispersion could be obtained at relatively lower temperature of 1,000°C. Under optimum UV excitation into 275 nm, the photoluminescence (PL) spectra display a series of 5D4–7FJ transitions of Tb3+ in (Gd1–xTbx)AlO3 system with the strongest green emission at ~546 nm. The overlapping between 8S7/2–6IJ intra f-f transition of Gd3+ and 4f8–4f75d1 transition of Tb3+ at 275 nm suggesting the Gd3+ → Tb3+ energy transfer, and the quenching contents of Tb3+ was found to be ~10 at%. The luminescent property of GdAlO3:Tb3+ phosphor could be further improved with molten salt incorporation. The optimal composition of molten salts was determined to be the mixture of NaCl/Na2SO4 (5 wt% NaCl), and the mass ratio of mixture molten salts to precursor was 2:1. The relationship between the luminescent property and molten salts composition were studied in detail.
关键词： energy transfer,GdAlO3:Tb3+ phosphor,molten salts,luminescent property
更新于2025-09-23 15:22:29
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X-ray scintillator Gd2O2S:Tb3+ materials obtained by a rapid and cost-effective microwave-assisted solid-state synthesis
摘要： In this work, the microwave-assisted solid-state (MASS) synthesis is reported as a rapid, cost-effective and environmental-friendly way to prepare Gd2O2S:Tb3+ X-ray scintillation standards. The preparation procedure employs active charcoal as the microwave susceptor, using a domestic microwave oven without a setup for special gases. The MASS method drastically reduced the synthesis time and energy consumption (up to 97% in nominal power) over previous reports using conventional solid-state methods. A single-step synthesis of 10 min is enough to yield highly crystalline powders starting from Gd2O3 and Tb4O7 precursors and elemental sulfur. In order to obtain 100% pure materials with superior scintillation efficiency, two microwave treatments of 25 min each are required. Due to the reducing CO atmosphere generated in situ by the active charcoal during the microwave synthesis, no Tb4+ impurity was found according to Synchrotron Radiation X-ray Absorption (SR-XAS) experiments. Spectroscopic studies were carried out using SR Vacuum-Ultraviolet (VUV) photoluminescence and SR X-ray Excited Optical Luminescence (XEOL). The material prepared by two-step synthesis exhibited a better scintillation performance owing to higher crystal purity and emission intensity, presenting versatility for technological applications such as X-ray imaging and scintillation bio-probing.
关键词： Synchrotron Radiation,Gd2O2S:Tb3+,Microwave-assisted solid-state synthesis,X-ray scintillation
更新于2025-09-23 15:21:01
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Fabrication and photoluminescent properties of Tb3+ doped carbon nanodots
摘要： Carbon nanodots (CNDs) doped with Tb ions were synthesized using different synthetic routes: hydrothermal treatment of a solution containing carbon source (sodium dextran sulfate) and TbCl3; mixing of CNDs and TbCl3 solutions; freezing-induced loading of Tb and carbon-containing source into pores of CaCO3 microparticles followed by hydrothermal treatment. Binding of Tb ions to CNDs (Tb-CND coupling) was confirmed using size-exclusion chromatography and manifested itself through a decrease of the Tb photoluminescence lifetime signal. The shortest Tb photoluminescence lifetime was observed for samples obtained by hydrothermal synthesis of CaCO3 microparticles where Tb and carbon source were loaded into pores via the freezing-induced process. The same system displays an increase of Tb photoluminescence via energy transfer with excitation at 320–340 nm. Based on the obtained results, freezing-induced loading of cations into CNDs using porous CaCO3 microparticles as reactors is proposed to be a versatile route for the introduction of active components into CNDs. The obtained CNDs with long-lived emission may be used for time-resolved imaging and visualization in living biological samples where time-resolved and long-lived luminescence microscopy is required.
关键词： freezing-induced loading,Tb3+ doping,photoluminescence,hydrothermal treatment,Carbon nanodots,CaCO3 microparticles
更新于2025-09-23 15:21:01
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Europium and terbium lanthanide ions co-doping in TiO2 photoanode to synchronously improve light-harvesting and open-circuit voltage for high-efficiency dye-sensitized solar cells
摘要： In this study, we explore the effects on the incorporation of europium (Eu3+) and terbium (Tb3+) rare-earth ions into titanium dioxide (TiO2) photoanodes in dye-sensitized solar cells (DSSCs). X-ray photoelectron spectroscopy (XPS) studies affirm that the Eu3+ ions are arranged at the cationic locales of Ti4+ in the matrix whereas the site inhabitance was remunerated by Tb3+ ions, supporting that the anatase phase stays unaltered without generating any new deformities. Additionally, the Eu3+ ions decidedly changed the conduction band minimum of TiO2, actually, Tb3+ ions contrarily conversion because of various vacant trap states in the band gap. Besides, the photoinduced electron transfer estimations show an efficient interfacial charge transfer for co-doped TiO2 (kET = 3.1 ns) contrasted with the bare TiO2 (2.6 ns). DSSCs based on Eu3+/Tb3+ co-doped TiO2 display higher efficiency (9.11%) than those for the bare TiO2 (7.20%) and the exclusively Eu3+ (8.01%) or Tb3+ (7.10%) doped samples, which is ascribed to the joined impact of a faster electron transportation and longer electron lifetime in the co-doped TiO2 film. This work may open another approach to further improve the performance of DSSCs by Eu3+/Tb3+ co-doping technique, advancing the development of DSSCs toward commercial applications.
关键词： Co-doping process,Europium (Eu3+)/terbium (Tb3+) lanthanide ions,Stability,Photoanodes,DSSCs,Titanium dioxide (TiO2) nanopowders
更新于2025-09-23 15:21:01
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Luminescence properties and energy transfer investigations of Ce3+ singly doped and Ce3+/Tb3+ codoped Na3LuSi2O7 phosphors
摘要： The Na3LuSi2O7:Ce3+ and Na3LuSi2O7:Ce3+, Tb3+ phosphors were synthesized under a weak reducing atmosphere by the traditional high temperature solid state reaction method. The synthesized phosphors were characterized by X-ray diffraction (XRD), Photoluminescence (PL) emission and excitation spectra. The effects of Ce3+ singly doped and Ce3+/Tb3+ codoped concentrations on the structure, luminescence properties and energy transfer of Na3LuSi2O7 phosphors were studied in detail. The results indicated that the energy transfers between Ce3+ and Tb3+ in the host occurred mainly via a dipole-quadrupole mechanism, and the critical distances of the ion pairs (Rc) were calculated by the quenching concentration method and spectral overlap method. Based on the good PL properties adjusting the doping concentration of the activators (Ce3+,Tb3+) might be promising as a host material for solid-state lighting and display fields.
关键词： Luminescence,Na3LuSi2O7:Ce3+,Tb3+ phosphors,Energy transfer
更新于2025-09-19 17:15:36
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Synthesis, characterization and luminescence properties of ZrBDC:Eu <sup>3+</sup> ,Tb <sup>3+</sup> nanoscaled metal organic frameworks
摘要： Zirconium nanoscaled metal–organic frameworks doped and co-doped with Eu3+ and/or Tb3+ (ZrBDC:Eu3+,Tb3+) have been synthesized by hydrothermal method using 1,4-dicarboxylic acid as linkers. The luminescence spectra obtained indicated that under 254 nm excitation, the as-synthesized ZrBDC:Eu3+,Tb3+ and ZrO2:Eu3+,Tb3+ nanoparticles have multicolour visible emissions at 473, 591, 612 and 701 nm assigned to the 5D0 → 7F1, 5D0 → 7F2, 5D0 → 7F3 and 5D0 → 7F4 transition of Eu3+ ions and at 488, 582 and 621 nm assigned to 5D4 → 7F, 5D4 → 7F5; 5D4 → 7F4 and 5D4 → 7F3 transitions of Tb3+ ions, respectively. The X-ray diffraction and field emission scanning electron microscopy results suggest that the ZrBDC:Eu3+,Tb3+ nanoscaled metal–organic frameworks can be used as precursors to design the tetragonal phase of ZrO2:Eu3+,Tb3+ nanoparticles with high purity and a narrow size distribution via heat treatment process. The as-prepared ZrO2:Eu3+,Tb3+ nanoparticles have size of about 10-15 nm with BET multipoint surface area of 162 m2/g.
关键词： ZrBDC:Eu3+,Tb3+,254 nm excitation,Zirconium metal–organic frameworks,nanoparticles,ZrO2:Eu3+,Tb3+
更新于2025-09-19 17:13:59
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Ca(Mg <sub/>0.8</sub> Al <sub/>0.2</sub> )(Si <sub/>1.8</sub> Al <sub/>0.2</sub> )O <sub/>6</sub> :Ce <sup>3+</sup> ,Tb <sup>3+</sup> Phosphors: Structure Control, Density-Functional Theory Calculation, and Luminescence Property for pc-wLED Application
摘要： A modified structure Ca(Mg0.8Al0.2)(Si1.8Al0.2)O6 (denoted as CMASO) from the evolution of CaMgSi2O6 (denoted as CMSO) codoped with Ce3+ and Tb3+ ions was designed successfully by solid reaction method for application in phosphor-converted white-light-emitting diode (pc-wLED). The Rietveld refinement of these two structures verified the changes derived from the replacement of some of the Mg2+ and Si4+ ions by Al3+ ions. The band gaps were calculated by density-functional theory (DFT) calculation method to verify the change of Al3+ ions replacing further, and the diffuse reflectance spectra (DRS) proved the veracity of the calculation result. The phosphors CMASO:Ce3+ showed blue emission excited by a wider excitation wavelength from 280 nm to 370 nm. The change of structure lead to the absorbable range broaden and the emission peak shifted to longer wavelength, compared with CMSO:Ce3+, although the amount of emitting center was the same. The reason for these phenomena was discussed in detail. The codoped phosphors CMASO:Ce3+,Tb3+ exhibited different emission colors from blue to green as the concentration of Tb3+ ions increased. Combined with commercial red phosphor CaAlSiN3:Eu2+ and ultraviolet LED (UV-LED) chips, the selected appropriate samples achieved white emission. The correlated color temperature (CCT) was 6137 K and the color rendering index (Ra) was 80.5, indicating that they could act as potential phosphors for possible applications in pc-wLED.
关键词： Ce3+,pc-wLED,DFT,luminescence property,Tb3+,Ca(Mg0.8Al0.2)(Si1.8Al0.2)O6,phosphor-converted white-light-emitting diode,density-functional theory
更新于2025-09-19 17:13:59
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Highly efficient near-UV-excitable Ca2YHf2Al3O12:Ce3+,Tb3+ green-emitting garnet phosphors with potential application in high color rendering warm-white LEDs
摘要： Inorganic phosphors with broadband near-ultraviolet (near-UV) excitation and efficient visible emissions are highly important for fabricating high-performance near-UV-pumped white light-emitting diodes (LEDs). Herein, we reported on novel efficient near-UV-excitable Ce3+/Tb3+ ions co-activated Ca2YHf2Al3O12 (CYHA) green-emitting garnet phosphors, which were successfully prepared through a high-temperature solid-state reaction process. X-ray diffraction, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, elemental mapping, photoluminescence, CIE color coordinates, internal and external quantum efficiency, and temperature-dependent emission spectra were used to characterize the samples. Interestingly, due to the efficient energy transfer from Ce3+ to Tb3+ ions in CYHA, the CYHA:Ce3+,Tb3+ samples presented a wide excitation band in the 370-470 nm region peaking around 408 nm owing to the 4f-5d transition of Ce3+ ions, and under 408 nm excitation they showed intense characteristic sharp green emissions around 543 nm corresponding to the 5D4→7F0-6 transitions of Tb3+ ions. The energy transfer mechanism from Ce3+ to Tb3+ ions was ascribed to the quadruple-quadruple interaction, and the energy transfer efficiency reached as high as 93.2%. Notably, the composition-optimized CYHA:0.03Ce3+,0.6Tb3+ sample exhibited high internal quantum efficiency (IQE) of 78.5% and external quantum efficiency (EQE) of 56%, which were much higher than those of the Tb3+ singly-activated CYHA:0.6Tb3+ sample (IQE = 8%, EQE = 2.2%). Finally, a prototype white LED device was made by combining a 400 nm near-UV-emitting LED chip with the phosphor blend of the as-prepared CYHA:0.03Ce3+,0.6Tb3+ green phosphors, commercial BaMgAl10O17:Eu2+ blue phosphors and commercial CaAlSiN3:Eu2+ red phosphors, which emitted bright warm-white light with good CIE chromaticity coordinates of (0.391, 0.356), low correlated color temperature of 3528 K and high color rendering index of 92.3 under 120 mA driven current. This work opens up new opportunities for the development of efficient color converters toward near-UV-pumped warm-white LEDs with high color rendering index.
关键词： white LEDs,green-emitting garnet phosphors,Ce3+/Tb3+ co-activated,near-UV-excitable,energy transfer
更新于2025-09-19 17:13:59