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oe1(光电查) - 科学论文

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出版时间
  • 2015
研究主题
  • Calibration process of OSL detectors
  • Iodine-131
  • OSL-BeO
  • Dosimetry of staff and patients
  • Optically Stimulated Luminescence (OSL)
应用领域
机构单位
  • Akdeniz University
550 条数据
?? 中文（中国） ▾

  • Up-Converting Lanthanide Fluoride Core@Shell Nanorods for Luminescent Thermometry in the First and Second Biological Windows - β-NaYF4: Yb3+, Er3+@SiO2 Temperature Sensor

    摘要： Up-converting core@shell type β-NaYF4:Yb3+-Er3+@SiO2 nanorods have been obtained by a two-step synthesis process, which encompasses hydrothermal and microemulsion routes. The synthesized nanomaterial forms stable aqueous colloids and exhibits a bright dual-center emission (λex= 975 nm), i.e. up-conversion luminescence of Er3+ and down-shifting emission of Yb3+, located in the first (I-BW) and the second (II-BW) biological windows of the spectral range. The intensity ratios of the emission bands of Er3+ and Yb3+ observed in the Vis-NIR range monotonously change with temperature, i.e. the thermalized Er3+ levels (2H11/2→4I15/2/4S3/2→4I15/2) and the non-thermally coupled Yb3+/Er3+ levels (2F5/2→2F7/2/4I9/2→4I15/2 or 4F9/2→4I15/2). Hence, their thermal evolutions have been correlated with temperature using the Boltzmann type distribution and 2-th order polynomial fits for temperature sensing purposes, i.e. Er3+ 525/545 nm (max Sr = 1.31 %K-1) and Yb3+/Er3+ 1010/810 nm (1.64 %K-1) or 1010/660 nm (0.96 %K-1). Additionally, a fresh chicken breast was used as a tissue imitation in the performed ex vivo experiment, showing the advantage of the use of NIR Yb3+/Er3+ bands, vs. the typically used Er3+ 525/545 nm band ratio, i.e. better penetration of the luminescence signal through the tissue in the I-BW and II-BW. Such nanomaterials can be utilized as accurate and effective, broad-range Vis-NIR optical, contactless sensors of temperature.

    关键词： Up-conversion luminescence,Luminescence intensity ratio (LIR),Functional nanomaterials,Rare earth ions,Energy transfer,Optical thermometer

    更新于2025-11-25 10:30:42

  • Scintillation Properties of Ce3+ Doped Silicon-Magnesium-Aluminum-Lithium Glass Scintillators by using Radiation Sources

    摘要： Glass scintillators can be doped with different elements to improve their luminescence properties. In this study, we present 0.5 wt% Ce3+-doped (58?x)SiO2-4MgO-18Al2O3-20Li2O and (58?x)SiO2-4MgO-18Al2O3-20LiF glass scintillators. We used a pulsed laser to measure the laser-induced emission spectrum and the decay time with decreasing temperature from 300 K to 10 K. The light intensity of both glass samples increased with decreasing temperature from 300 K to 10 K. Additionally, the two glass samples exhibited a fast decay time of approximately 25 ns. In the photo-induced spectrum, an excitation peak at 312 nm and two emission peaks, at 370 nm and 700 nm, were observed in both the glass samples. The X-ray-induced emission intensity of former is approximately six times higher than that of latter, and only former glass sample exhibits a proton-induced emission spectrum.

    关键词： Luminescence,Decay time,Ce3+,Glass scintillator

    更新于2025-11-25 10:30:42

  • Eu-doped layered yttrium hydroxides sensitized by series of benzenedicarboxylate and sulphobenzoate anions

    摘要： A number of Eu-doped layered yttrium hydroxides intercalated with various benzenedicarboxylate (phthalate, isophthalate and terephthalate) and sulphobenzoate (2-, 3- and 4-sulphobenzoate) anions was obtained using hydrothermal microwave (HTMW) treatment. For the first time, phthalate, isophthalate and sulphobenzoate anions were intercalated into layered rare-earth hydroxides (LRHs). Two approaches to the synthesis of intercalated layered yttrium hydroxides were used: ion exchange reactions and homogeneous hydrolysis of rare-earth cations in the presence of the intercalated anion. Ion-exchange reactions between layered rare-earth hydroxides and a series of benzenedicarboxylic and sulphobenzoic acid salts were performed under conditions of HTMW treatment, which significantly increased the rate of intercalation. The structure of the first representative of layered rare-earth hydroxides intercalated with sulphobenzoate-type anions, namely layered yttrium hydroxide intercalated with 4-sulphobenzoate of composition Y3(OH)7(C7H4O5S)·H2O, was solved. Intercalation of benzenedicarboxylate and sulphobenzoate anions into Eu-doped layered yttrium hydroxides led to a substantial sensitization of Eu3+ luminescence. The local symmetry of Eu3+ was greatly decreased by intercalation of benzenedicarboxylate and sulphobenzoate anions.

    关键词： Layered rare-earth hydroxides,anion exchange,LRH,hydrothermal microwave treatment,luminescence,hybrid materials

    更新于2025-11-21 11:20:42

  • Photoluminescent porous aerogel monoliths containing ZnEu-complex: the first example of aerogel modified with a heteronuclear metal complex

    摘要： A procedure for the chemical immobilization of a new ZnII–EuIII heterobimetallic complex in the SiO2 aerogel matrix has been developed. In this Zn–Eu complex, a peripheral non-luminescent Zn ion acts as a binder to a silica matrix and prevents direct interaction of rare-earth ions with OH? and NH? groups in the silica matrix, which would have a detrimental effect on the luminescence of lanthanides. The procedure includes the synthesis of complexes, co-gelation of the obtained complex with SiO2 sol, the washing of lyogels, and their subsequent supercritical drying in CO2. The composition and properties of the obtained aerogels were investigated using a low-temperature nitrogen adsorption technique, helium pycnometry, FTIR, Raman, UV–visible, and luminescence spectroscopy, XPS, PXRD, SEM, TEM, TGA combined with mass spectrometry, and small-angle neutron scattering. The aerogels modi?ed with the ZnII–EuIII complex demonstrated strong red luminescence upon excitation with UV light.

    关键词： Aerogel,Silica,Heteronuclear metal complex,Luminescence,Structure

    更新于2025-11-21 11:20:42

  • Traps distribution in sol-gel synthesized ZnO nanoparticles

    摘要： The distribution of shallow traps within the sol-gel synthesized ZnO nanoparticles was investigated using thermoluminescence (TL) experiments in the 10–300 K temperature range. TL measurements presented two overlapped peaks around 110 and 155 K. The experimental technique based on radiating the nanoparticles at different temperatures (Texc.) between 60 and 125 K was carried out to understand the trap distribution characteristics of peaks. It was observed that peak maximum temperature shifted to higher values and activation energy (Et) increased as irradiating temperature was increased. The Et vs. Texc. presented that ZnO nanoparticles have quasi-continuously distributed traps possessing activation energies increasing from 80 to 171 meV.

    关键词： Luminescence,Nanoparticles,Defects

    更新于2025-11-21 11:18:25

  • On the Blue Emitting Phosphor Na <sub/>3</sub> RbMg <sub/>7</sub> (PO <sub/>4</sub> ) <sub/>6</sub> :Eu <sup>2+</sup> Showing Ultra High Thermal Stability

    摘要： This work concerns a novel blue emitting LED phosphor activated by Eu2+. It turned out that this luminescent material can be efficiently pumped by near UV or UV-A radiation sources while it exhibits a high quantum yield for a doping level between 0.3 and 3.0%. More impressively, the material has a very high quenching temperature T1/2 and will thus be applicable on-chip in high power phosphor converted LEDs or even in laser diodes. The emission and thermal stability is almost identical to that of BAM:Eu2+ while the absorption band is broader and reaches into the near UV range. Therefore, Na3RbMg7(PO4)6:Eu2+ is a promising candidate as a blue emitter in high CRI full conversion LEDs. To investigate the site preference of Eu2+, DFT and Ligand Field Theory based calculations were performed to successfully predict the emission spectrum. An unusual decay behavior was observed at low temperatures and the underlying mechanism involving spin-forbidden transitions of Eu2+ is discussed.

    关键词： high thermal stability,solid state lighting,Eu2+ luminescence,near UV LED,high CRI,decay time,Blue photoluminescence

    更新于2025-11-21 11:18:25

  • One-Pot Synthesis of Gel Glass Embedded with Luminescent Silicon Nanoparticles

    摘要： Preparation of highly luminescent glasses involves expensive and complicated processes and usually requires high temperature. In this work, we show that luminescent silicon (Si) nanoparticle (NP)- embedded silicate gel glasses can be developed under near-ambient conditions by a remarkably simple, one-pot strategy, without using any sophisticated instrumentation or technique. Simultaneous hydrolysis and reduction of (3-aminopropyl)triethoxysilane leads to the formation of colloidal Si nanocrystals that can be transformed to a glassy phase upon slow evaporation followed by freezing. Structural investigations reveal the formation of a sodium silicate gel glass framework having discernible shear bands, along with embedded Si NPs. High photoluminescence quantum yield (ca. 35?40%), low glass-transition temperature (Tg ≈ 66?73 °C), strain-tolerant mechanical stability, and inexpensive preparation make the glass attractive for applications as display materials and photonic converters.

    关键词： luminescence,silicon,gel glass,nanoparticles,photon conversion

    更新于2025-11-21 11:01:37

  • Broad-band emission and color tuning of Eu3+-doped LiCa2SrMgV3O12 phosphors for warm white light-emitting diodes

    摘要： In this study, series of Eu3+-doped LiCa2SrMgV3O12 (LCSMV) phosphors with broad-band emission and color tunable feature were prepared via solid phase reaction. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) results presented a pure cubic phase product with micron-sized and homogeneous distribution of element. Their spectroscopic properties were investigated systematically by photoluminescence excitation (PLE) and emission (PL) spectra, temperature-dependent PL spectra and luminescence decay curves. The LCSMV phosphors displayed a strong absorption to ultraviolet light and a broad cyan emission. Moreover, in Eu3+-doped LCSMV phosphors, Eu3+ ion characteristic emissions at 589, 610, 651 and 705 nm, attributing to the 5D0→7F1, 7F2, 7F3 and 7F4 transitions, were observed. Along with Eu3+ ion concentrations increasing, the emission colors could be readily tuned from cyan to orange and the decay lifetimes of (VO4)3- became shorter. Meanwhile, electric dipole-dipole interaction was responsible to energy migration from (VO4)3- groups to Eu3+ ions. Further, the quantum efficiency (QE) values were estimated to be 32.5% for LCSMV host and 39.3% for LCSMV: 0.01Eu3+ sample. Finally, a LED lamp was prepared by integrating the blend of the LCSMV: 0.01Eu3+ phosphors and commercial blue-emitting BaMgAl10O17:Eu2+ phosphors with NUV chip (365 nm) and exhibited warm white light (CCT = 3655 K, Ra = 90), which may be applied in lighting and display field.

    关键词： Self-activated luminescence,Color tunable,Light-emitting diode,Vanadate phosphor,Color rendering index,Broad-band emission

    更新于2025-11-20 15:33:11

  • Synthesis, energy transfer and multicolor luminescent property of Eu3+-doped LiCa2Mg2V3O12 phosphors for warm white light-emitting diodes

    摘要： In this study, Eu3+-doped LiCa2Mg2V3O12 (LCMVO) phosphors with multicolor luminescent property were prepared by the solid phase reaction. Their structure, morphology and luminescent property were studied systematically by X-ray diffraction, scanning electron microscope and photoluminescence spectra. The LCMVO phosphors showed pure cubic crystal structure with space group (3Ia d ) and irregular spherical morphology. The excitation spectra showed a strong absorption to ultraviolet light. Under the excitation wavelength at 360 nm, they exhibited a cyan emission with a luminescence center at 520 nm. When Eu3+ ions were doped into LCMVO system, the Eu3+ characteristic emissions were also observed and the emission colors were tuned from cyan to orange via adjusting Eu3+ ion concentration. Further, electric dipole-quadrupole interaction and luminescence decay curves were adopted to explain the energy transfer from (VO4)3- to Eu3+. The emission spectra of as-obtained phosphors at different temperature were measured to evaluate their thermal stability. The quantum efficiency values were measured to be 42.5% for LCMVO host and 38.6% for LCMVO: 0.01Eu3+ sample. The final prepared LED lamp showed easeful warm white light with suitable Ra of 89 and CCT of 3847 K, respectively. These results suggest LCMVO phosphors may be applied in near ultraviolet chip-excited white light-emitting diodes.

    关键词： energy transfer,multicolor luminescent,self-activated luminescence,excitation and emission spectra,vanadate phosphor,UV-LED

    更新于2025-11-20 15:33:11

  • Novel Ca2GdTaO6:Mn4+,M (M = Li+, Na+, K+, and Mg2+) red phosphors for plant cultivation light-emitting diodes: Synthesis and luminescence properties

    摘要： Recently, Mn4+-activated red phosphors are becoming potential color converters for application in indoor plant cultivation light-emitting diodes, owing to their satisfactory luminescence properties as well as low cost. Herein, novel Mn4+-activated double perovskite-type Ca2GdTaO6 phosphors have been synthesized by a high-temperature solid-state reaction method in air, which exhibited a broad excitation band with two peaks locating at 355 nm and 496 nm in range of 250-600 nm and had an intense red emission peaking at 676 nm due to Mn4+:2Eg→4A2g spin-forbidden transition ranging from 650 to 750 nm under 355 nm excitation. Concentration-dependent luminescence properties were studied. The optimal Mn4+ doping concentration in Ca2GdTaO6 host was 0.004, and the concentration quenching mechanism was determined to be a dipole-dipole interaction among Mn4+ ions. Furthermore, the Ca2GdTaO6:0.004Mn4+ phosphor possessed the internal quantum efficiency up to 33% when excited at 355 nm. Besides, the decay lifetimes of Ca2GdTaO6:Mn4+ presented a reasonable downward trend with increasing Mn4+ concentration. In addition, the effect of charge compensation (co-doping of Li+, Na+, K+, and Mg2+ ions) on the luminescent properties of Ca2GdTaO6:Mn4+ phosphors was also investigated.

    关键词： Indoor plant cultivation,Ca2GdTaO6,Mn4+,Double perovskite,Luminescence properties,Red phosphor

    更新于2025-11-20 15:33:11