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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） ▾

  • Control of Circularly Polarized Luminescence by Orientation of Stacked π-Electron Systems

    摘要： New planar chiral building blocks based on 4,7,12,15-tetrasubstituted [2.2]paracyclophanes were obtained via a synthetic route involving an optical resolution step. Planar chiral enantiomers, comprising of two fluorophores that were stacked to form a V-shaped higher-ordered structure, were synthesized from these building blocks. The V-shaped molecules emitted intense circularly polarized luminescence (CPL). Their chiroptical properties were compared with those of X-shaped molecules bearing the same two fluorophores stacked together. CPL sign of the X-shaped molecule was opposite to that of the V-shaped molecule, which is supported by the theoretical results, indicating that CPL sign can be controlled by the orientation of the stacked fluorophores.

    关键词： circularly polarized luminescence,planar chirality,higher-ordered structure,[2.2]paracyclophane

    更新于2025-09-23 15:23:52

  • Strong Emission Enhancement in pH-Responsive 2:2 Cucurbit[8]uril Complexes

    摘要： Organic fluorophores, particularly stimuli-responsive molecules, are very interesting for biological and material sciences applications, but limited by aggregation- and rotation-caused photoluminescence quenching. A series of easily accessible bipyridinium fluorophores is reported, whose emission is quenched by a twisted intramolecular charge transfer (TICT) mechanism. Encapsulation in a cucurbit[7]uril host yields a 1:1 complex exhibiting a moderate emission increase due to destabilization of the TICT state inside the apolar cucurbituril cavity. A much stronger fluorescence enhancement is observed in 2:2 complexes with the larger cucurbit[8]uril, which is caused by additional conformational restriction of rotations around the aryl-aryl bonds. As the cucurbituril complexes are pH switchable, this system represents an efficient supramolecular ON/OFF fluorescence switch.

    关键词： restriction of intramolecular motion,luminescence,host-guest complex,fluorescence enhancement,Cucurbituril

    更新于2025-09-23 15:23:52

  • Construction of a Noncentrosymmetric Luminescent Coordination Polymer from [BaL <sub/>3</sub> ] Unit (L = Pyridine-2,6-dicarboxylate Acid) and Li(I) Ion

    摘要： This work presents the synthesis, crystal structure and properties of a novel noncentrosymmetric (NCS) coordination polymer (CP), namely, (Me2NH2)3[BaLi(2,6-PyDC)3(H2O)] (1) (2,6-PyDC = pyridine-2,6-dicarboxylate acid), which represents the first example of BaLi-CPs with 2,6-PyDC ligand. Single-crystal X-ray structural analysis reveals that the compound features a two-dimensional (2D) layered structure. The simplified structure of each layer belongs to the hcb topology. The second harmonic generation (SHG) response of 1 is about 0.5 times that of KH2PO4 (KDP) marker. What is more, 1 emits bright blue light upon the excitation of 365 nm UV light with the quantum yield (QY, Φ) of 1.63%. The successful construction of this compound convinces the feasibility of constructing NCS CPs via the combination of [BaL3] unit and Li(I) ion.

    关键词： noncentrosymmetric,heterometallic complex,luminescence,nonlinear optics

    更新于2025-09-23 15:23:52

  • Progress in development of a new luminescence setup at the FinEstBeAMS beamline of the MAX IV laboratory

    摘要： FinEstBeAMS is a new materials science beamline at the 1.5 GeV storage ring of the MAX IV Laboratory in Lund, Sweden. It has been built based on grazing incidence monochromatization of synchrotron light, which allows to cover a remarkably wide excitation energy range from ultraviolet to soft x-rays (4.5-1450 eV). A new mobile luminescence spectroscopy end station has been commissioned with design benefitting from the advantages of a high flux elliptically polarizing undulator light source. We report on the design of the luminescence end station, its technical realization and performance achieved so far. Special attention is paid to the experimental challenges for luminescence spectroscopy under grazing incidence excitation conditions. The first luminescence results obtained demonstrate a reliable performance of the advanced setup at FinEstBeAMS.

    关键词： Luminescence spectroscopy,synchrotron radiation,wide gap compounds,VUV – XUV photoexcitation

    更新于2025-09-23 15:23:52

  • Development of a 2D dosimeter using the optically stimulated luminescence of NaMgF3:Eu with CCD camera readout

    摘要： A two-dimensional (2D) dosimeter has been developed using tissue-equivalent NaMgF3:Eu as a radiation-sensing material. The bulk compound shows optically stimulated luminescence (OSL) after irradiation in the form of 359 nm Eu2+ emission and where the OSL stimulation occurs at wavelengths above 400 nm. The OSL integrated intensity is shown to be linear up to at least 100 Gy when stimulated with 445 nm light. When the OSL is detected using a thermoelectrically cooled CCD camera, 2D X-ray images can be obtained and the measured intensity is proportional to the total radiation dose. NaMgF3:Eu can be incorporated into epoxy to produce imaging films and both the bulk compound and a film are characterised using the 2D setup. The noise equivalent dose in 2D for the film is determined to be 14 mGy. The modulation transfer function (MTF) is determined and the spatial resolution at MTF = 0.2 is 2.9 lp/mm for the bulk material and 1.25 lp/mm for the film. Our results show that NaMgF3:Eu has potential in the field of 2D dosimetry, where the response to radiation is linear to high doses, sensitive to low doses, and doses can be resolved with a spatial resolution below 1 mm.

    关键词： fluoroperovskite,optically stimulated luminescence,dosimetry,NaMgF3

    更新于2025-09-23 15:23:52

  • Divergent Terpyridine-Based Coordination for the Construction of Photoactive Supramolecular Structures

    摘要： Exploring new materials to manipulate luminescent radiation and investigate the interaction of light and matter is one of the most compelling prospects of our century. Supramolecular chemistry has unraveled the opportunity to synergistically combine the chemical and optoelectronic properties of the most diverse classes of compounds. Among these, terpyridines have acted as pivotal ligand units that enable self-assembly of multicomponent chromophoric systems. In this review we therefore elucidate the metal-coordinating ability of these materials, that promote a plethora of aggregation-induced phenomena. In particular, fluorescence tuning, reversible stimuli-responsive phosphorescence enhancement and low-dimensional complexation have been demonstrated for carbon and sulfur based terpyridine oligomeric structures. Common thread of such processes is the versatile application of light as a trigger for spectroscopic investigation and output for superior optical, medical and sensing devices.

    关键词： Luminescence,Terpyridine,Supramolecular chemistry,Polymers

    更新于2025-09-23 15:23:52

  • Synthesis, Structure, and Photoluminescence Properties of a Metal-Organic Framework with Hexagonal Channels: Selective Turn-On Sensing for Mg <sup>2+</sup> Ion

    摘要： A three-dimensional Cd2+ framework (1) with wide one-dimensional hexagonal channels was prepared based on a tripodal tricarboxylate ligand possessing nitrogen donor atoms. The Cd atoms form a chain structure bridged by carboxylates and aqua ligands. Upon Mg2+ ion capture, the fluorescence emission of this porous material was 5.2 times greater than its Mg2+-free fluorescence. To the best of our knowledge, such enhancement has not been previously reported for metal–organic framework sensory systems. The sensing performance of 1 is reversible over repeated cycles of Mg2+ inclusion and release, revealing the reusability of this material. In the presence of other tested metal ions, Mg2+ ions were selectively detected owing to the operation of this “turn-on” mechanism. Thus, this platform is a promising sensor material for selective Mg2+ ion recognition.

    关键词： Sensors,Luminescence,Metal-organic frameworks

    更新于2025-09-23 15:23:52

  • Highly efficient green upconversion luminescence of ZnMoO4:Yb3+/Er3+/Li+ for accurate temperature sensing

    摘要： Upconversion luminescence and optical temperature sensing properties of Yb3+/Er3+/Li+ tri-doped ZnMoO4 phosphors were investigated. It has been demonstrated that Li+ doping affected not only the local symmetry of Yb3+ and Er3+ but also the distribution of them in the host lattice. As a result, the significantly improved green upconversion luminescence was obtained when excited at 980 nm. The pumping power dependent photo-thermal behavior was used to evaluate the reliability of upconversion temperature sensing. An accurate temperature scale was established by eliminating the impact of thermal effect, and the sensing ability was evaluated via a comparison with the results reported in literatures.

    关键词： Li+ doping,Upconversion luminescence,Thermal effect,Temperature sensing,ZnMoO4

    更新于2025-09-23 15:23:52

  • Comparative investigations of gadolinium based borate glasses doped with Dy3+ for white light generations

    摘要： Gadolinium-based borate glasses doped with Dy3+ ions were developed by melt quenching technique for white light generation. The title glasses were examined by XRD, optical absorption spectra and Photoluminescence spectra. From photoluminescence emission spectra, the higher intensity peak was observed at 575 nm (4F9/2 → 6H13/2) for present glass samples. The experimental decay rate (τexp) of 4F9/2 transition of Dy3+ ions were found to be a decline in increasing of Dy2O3 content. The Inokuti-Hirayama (IH) model is used to explain the non-exponential decay time by putting S=6, which confirmed that the energy is transfer through cross-relaxation is of dipole–dipole nature among the Dy2O3. The values of color coordinates match with the range of white light of chromaticity (CIE) diagram. The color chromaticity coordinates (u, v) and color correlated temperature (CCT) values for present glasses were correlated with standards, which are closely related to the standard, therefore, the prepared glasses might be helpful for different photonic applications such as white LEDs.

    关键词： luminescence,glasses,borate,spectra,Gadolinium

    更新于2025-09-23 15:23:52

  • Coordination Polymers Based on Organic–Inorganic Hybrid Rigid Rod Comprising a Backbone of Anderson-Evans POMs

    摘要： To construct polyoxometalates coordination polymers (PCPs), we prepared two pyridine ligand functionalized Anderson POMs: (TBA)3[MnMo6O18((OCH2)3CN=CH-4-Py)2]·DMF ((TBA)3POM-1, TBA = tetrabutyl ammonium, Py = pyridine) and (TBA)3[MnMo6O18((OCH2)3CN=CH-3-Py)2] ((TBA)3POM-2) via the post-functionalization of (TBA)3[MnMo6O18((OCH2)3CNH2)2] (Anderson-NH2) by 4-pyridinealdehyde and 3-pyridinealdehyde, respectively. They are characterized using X-ray single crystal diffraction, MALDI-TOF MS, ESI MS, FT-IR, UV-Vis and 1H NMR . The self-assembly of (TBA)3POM-1 and [Cu(PPh3)2(CH3CN)2]ClO4 (CuP2) in the mole ratios of 1 : 2 and 1 : 3, both gave the same 1D double chain with the molecular formula of (NBu4)n{[Cu(PPh3)2]2(POM-1)}n (7.5DMF)n (1). On the contrary, the self-assembly of (TBA)3POM-2 and CuP2 in the mole ratio of 1:2 yields a 2D coordination polymer of (TBA)n{[Cu(PPh3)2]2(POM-2)}n·(2DMF)n (2), while that self-assembly process in the mole ratio of 1:3 results in different 2D coordination polymer of {[Cu(PPh3)2]3(POM-2)·(CH3CN)}n·(5CH3CN)n (3). Compounds 1-3 can keep their skeleton structures below 230oC. They exhibit intense green emission (496nm for 1; 537nm for 2; 530nm for 3) by ultra-violet irradiation (327nm for 1; 303nm for 2; 331nm for 3), which can be tentatively ascribed as ILCT with metal perturbation.

    关键词： Luminescence,Polyoxometalates,Pyridine,Coordination Polymer,Copper (I)

    更新于2025-09-23 15:23:52