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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） ▾

  • A multi-color and white-light emissive cucurbituril/terpyridine/lanthanide supramolecular nanofiber

    摘要： Multi-color and white light luminescence materials based on supramolecular assemblies are attractive because of their potential applications in advanced light-emitting material. Herein, a cucurbit[8]uril-enhanced lanthanide luminescent supramolecular assembly was constructed in a facile but efficient way using terpyridine imidozalium cations, cucurbit[8]urils and rare earth ions such as Tb3+ and Eu3+. Significantly, the resultant fibrous supramolecular assembly, with an average width of 15 nm, could emit remarkable lanthanide luminescence, which was ten times higher than the corresponding terpyridine/Ln3+ without cucurbit[8]uril. And the solid state luminescence of supramolecular assembly could be smartly and easily turned among blue, green, red and white by adjusting the molar ratios between Tb3+ and Eu3+. The enhanced white-light emission by supramolecular strategy may provide a new approach for smart and tunable solid luminescent materials.

    关键词： Cucurbit[8]uril,White-light emission,Supramolecular chemistry,Host-guest interaction,Lanthanide luminescence

    更新于2025-09-23 15:23:52

  • Phase-dependent photoluminescence of non-symmetric 2,1,3-benzothiadiazole liquid crystals

    摘要： In order to understand the effect of disubstitution on calamitic liquid crystals, a series of non-symmetric 2,1,3-benzothiadiazole compounds were synthesized and characterized. These specific molecular architectures without the C2 axis were prepared to investigate their mesomorphism and physical properties and to compare them with symmetric molecules. Their liquid crystalline behavior was studied by differential scanning calorimetry, polarized optical microscopy and X-ray diffraction. The thermal properties evidenced the influence of non-symmetric design on the formation of liquid crystalline phases. Photophysical studies were performed in solution and with films, where these materials displayed intense photoluminescence between 500–650 nm, high quantum yields (ΦF = 0.62 – 0.96) and strong solvatochromism. Photoluminescence was measured as a function of temperature, displaying a strong dependence on the phase.

    关键词： Heterocycles,Liquid crystals,Luminescence,2,1,3-Benzothiadiazole

    更新于2025-09-23 15:23:52

  • UV luminescence characterisation of organics in Mars-analogue substrates

    摘要： Detection of organic matter is one of the core objectives of future Mars exploration. The ability to probe rocks, soils, and other geological substrates for organic targets is a high priority for in situ investigation, sample caching, and sample return. UV luminescence—the emission of visible light following UV irradiation—is a tool that is beginning to be harnessed for planetary exploration. We conducted UV photoluminescence analyses of (i) Mars analogue sediments doped with polyaromatic hydrocarbons (PAHs; <15 ppm), (ii) carbonaceous CM chondrites and terrestrial kerogen (Type IV), and (iii) synthetic salt crystals doped with PAHs (2 ppm). We show that detection of PAHs is possible within synthetic and natural gypsum, and synthetic halite. These substrates show the most apparent spectral modifications, suggesting that the most transparent minerals are more conducive to UV photoluminescence detection of trapped organic matter. Iron oxide, ubiquitously present on Mars surface, hampers but does not completely quench the UV luminescence emission. Finally, the maturity of organic carbonaceous material influences the luminescence response, resulting in a reduced signal for UV excitation wavelengths down to 225 nm. This study demonstrates the utility of UV luminescence spectroscopy for the analysis of mixed organic-inorganic materials applicable to Mars exploration.

    关键词： UV luminescence,Spectroscopy,Analogue,Organic,Mars

    更新于2025-09-23 15:23:52

  • Structural and photoluminescence investigations of Cr3+ mixed Li2O—Bi2O3—ZrO2—SiO2 glass ceramics for optoelectronic device application

    摘要： Chromium oxide mixed Li2O―Bi2O3―ZrO2―SiO2 (Cr3+:LBZS) glasses were crystallized by heat treatment. Structural (X-ray di?raction, surface morphology, energy dispersion, DTA, FT-IR and Raman) and spectroscopic (optical absorption and luminescence), of these Cr3+:LBZS glass ceramics were studied. XRD pattern of Cr3+: LBZS glass ceramic samples exhibited distinct crystalline peaks. SEM images of the Cr3+: LBZS glass ceramic materials have revealed well identi?ed and distributed crystals of reformed size. The glass transition (Tg) and various crystallization temperatures (Tc1), (Tc2) and (Tc3) of these ceramics were identi?ed by DTA analysis. The shift in the wavenumbers of di?erent symmetrical and asymmetrical band positions of these glass ceramics were analysed by FT-IR and Raman studies. The optical bandgap (Eo), CFSE (Dq) and nephelauxetic ratio (β) were calculated. Photoluminescence properties were also investigated.

    关键词： Luminescence,FTIR,DTA,Structure,Cr3+: LBZS glass ceramics,Optical

    更新于2025-09-23 15:23:52

  • Effect of the Chirality of Counter Anions on the Vapochromic Behavior of Luminescent Pt(II) Complexes

    摘要： New luminescent Pt(II) complexes with the chiral counter anions [PtCl(tpy)](L-Hta) (1-L) and [PtCl(tpy)](DL-Hta) (1-DL; tpy = 2,2’:6’,2’’-terpyridine; L-H2ta = L-tartaric acid; DL-H2ta = racemic tartaric acid) were synthesized and their vapochromic behavior was evaluated. Single crystal X-ray analysis revealed that the stacked square-planar Pt(II) molecules in anhydrous 1-DL formed a one-dimensional columnar structure with weak intermolecular Pt···Pt interactions, while in anhydrous 1-L the Pt(II) molecules were dimerized with Pt…Pt interactions to form a zig-zag stacked column. These differences were attributed to the different hydrogen bonding in the DL- and L-Hta? ions. The dihydrates of 1-DL and 1-L displayed near-identical crystal structures with comparable emission spectra derived from 3π–π* ligand emission. Both dihydrates exhibited MeOH-vapor-induced dehydration to form the anhydrous complexes. These presented broad 3MMLCT emission (549 and 565 nm, respectively), affected by the degree of intermolecular Pt···Pt interactions.

    关键词： luminescence,chromophores,platinum

    更新于2025-09-23 15:23:52

  • Tunable photoluminescence properties and energy transfer of Ca5(BO3)3F: Tb3+/Eu3+ phosphors for solid state lighting

    摘要： A series of Ca5(BO3)3F: Tb3+/Eu3+ phosphors have been prepared via solid-state reaction. Phase purity and crystal structure of as-prepared samples are confirmed by X-ray diffraction measurements. The emission intensity of Ca5(BO3)3F: Tb3+ with Li+, Na+, K+ as charge compensators are remarkably enhanced, and the sample in presence of Na+ exhibits the strongest emission intensity. The emission spectra and fluorescence decays confirm the presence of efficient energy transfers from Tb3+ to Eu3+ in Ca5(BO3)3F: Tb3+/Eu3+ phosphors. The energy transfer mechanism between Tb3+ and Eu3+ has been proven to be resonant type via the electric dipole-dipole interaction. The thermal quenching temperature T50 obtained from the temperature-dependent emission spectra is 478 K, demonstrating a high thermal stability of the as-obtained Ca5(BO3)3F: Tb3+/Eu3+ phosphors. Moreover, by increasing the molar ratio of Eu3+ to Tb3+, the emission colors of Ca5(BO3)3F: Tb3+/Eu3+ phosphors can be tuned from green to orange, and then to red. These results demonstrate that the as-obtained Ca5(BO3)3F: Tb3+/Eu3+ phosphors may have potential applications in solid-state lighting fields.

    关键词： Energy transfer,Ca5(BO3)3F,Phosphors,Tunable luminescence,Solid-state reaction

    更新于2025-09-23 15:23:52

  • Versatile and Switchable Responsive Properties of a Lanthanide-Viologen Metal-Organic Framework

    摘要： Metal–organic frameworks (MOFs) provide intriguing platforms for the design of responsive materials. It is challenging to mobilize as many components as possible of a MOF to collaboratively accomplish multiple responsive properties. Here, reversible photochromism, piezochromism, hydrochromism, ionochromism, and luminescence modulation of an ionic Eu(III) MOF is reported furnished by cationic electron-deficient viologen units and exchangeable guest anions. Mechanistically, the extraordinarily versatile responsive properties are owed to electron transfer (ET), charge transfer (CT), and energy transfer, involving viologen as electron acceptor, anion as electron donor, luminescing Eu(III) as energy donor, and anion-viologen CT complex or ET-generated radical as energy acceptor (luminescence quencher). Moreover, guest anions and waters provide flexible handles to control the ET-based responsive properties. Water release/reuptake or exchange with organic solvents can switch on/off the response to light, while reversible anion exchange can disenable or awaken the responses to pressure, light, and water release/reuptake. The impacts of water and anions on ET are justified by the high polarity and hydrogen-bonding capability of water, the different electron donor strength of anions, and the strong I?-viologen CT interactions. The rich responsive behaviors have great implications for applications such as pressure sensors, iodide detection, and chemical logic gates.

    关键词： metal–organic frameworks,electron transfer,charge transfer,luminescence switches,piezochromism

    更新于2025-09-23 15:23:52

  • Low-temperature red long-persistent luminescence of Pr3+ doped NaNbO3 with a perovskite structure

    摘要： Long persistent luminescence (LPL) phosphors can keep emitting light after the removal of excitation sources under thermal disturbances at room temperature, which provides a wide application from emergency signs to in vivo biological imaging. Unfortunately, these phosphors will exhibit poor LPL performance once the thermal activation energy is not sufficient to release the captured carriers from the traps at low-temperature. Herein, a red phosphor of Pr3+ doped NaNbO3 with a perovskite structure is designed, which realizes a low-temperature LPL. The red emission (λem=612 nm) is ascribed to the 1D2→3H4 transition of Pr3+ ions, and LPL can be visually recognized over 16 hours after the removal of the excitation source at 200 K. Low-temperature thermoluminescence curves, temperature-dependent photoluminescence spectra indicate that abundant traps (≤ 0.6 eV) exist in NaNbO3: Pr3+, which is critical for ensuring the low-temperature LPL. The investigation on low-temperature LPL properties of NaNbO3: Pr3+ helps us to reveal the importance of defects structure, and provides new opportunities in exploring luminescence materials applied in an extreme conditions.

    关键词： low-temperature,persistent luminescence,defects structure,phosphors

    更新于2025-09-23 15:23:52

  • Multicolour tuning and perfect white emission from novel PbWO4:Yb3+:Ho3+:Tm3+ nanophosphor

    摘要： Upconverting (UC) nanoparticles have been an eye-candy for the people of optical world in the past decade because of their stupendous luminescence properties, photostability, effective quantum efficiency and most of all for its voluminous power of converting Infra-red (IR) waves into visible radiation. In this article, we have successfully synthesized novel Yb3+, Ho3+, Tm3+ doped lead tungstate nanophosphor by facile hydrothermal technique, where the product can also be scaled up in a large quantity. The phase purity and structure of the samples were characterized using X-Ray diffractometer and the structural morphology was studied using FEG TEM which shows formation of nano sphere of about 30-40 nm. Photoluminescence studies of the nanophosphor were carried out using spectroflurophotometer which shows red, green and blue emission due to the energy level transitions viz 5F5 → 5I8 and 5S2/5F4 → 5I8 of Ho3+,1G4 → 3H6, of Tm3+ respectively. The pumping power variation data was recorded using variable power which implies that the UC mechanism is a mixture of two and three photon process. The biexponential decay kinetics experiment was also done using the pulse mood laser source which shows the mean lifetime of 21.09 μs, 12.03 μs and 29.43 μs for blue, green and red emission respectively. Due to the perfect intermixing of the red, green and blue emission in the optimum sample a bright white light is obtained with CIE coordinates indexed as (0.34573,0.3449). The correlated colour temperature (CCT) values of the bright white light was calculated using McCamy’s approximations and it was found to be 4960 K which is almost equivalent to the colour “Horizon Daylight”. The colour temperature found after calculation, must be eye-friendly and hence perfect for using in optoelectronics applications.

    关键词： Luminescence,White Light,Upconversion,Hydrothermal,Nanophosphor

    更新于2025-09-23 15:23:52

  • Synthesis, crystal structure, vibrational and optical properties of a new Bi(III) halide complex: (C9H13N2O2)2Bi2Cl8

    摘要： A new Bi(III) halide complex, (C9H13N2O2)2Bi2Cl8, was successfully grown by slow evaporation method. The structure of this hybrid compound was determinated by single crystal X-ray diffraction and further characterized by IR and RAMAN spectra, UV-Visible, luminescence and DFT calculations. This compound crystallizes in the monoclinic system P21/n space group with the following lattice parameters: a = 10.2036 (4), b = 9.8723 (4), c = 14.5920 (6) ?, ? = 99.899 (4)°, V = 1448.01 (10) ?3 and Z =2. The crystal structure of this compound was solved by direct methods and refined to R = 0.038 (wR = 0.079), based on 4118 unique observed reflections. The crystal structure consists of a 1-(2-furoyl)piperazinium cation and discrete (0D) anion built up of edge-sharing bioctahedra which are linked by bifurcated N-H…Cl and N-H…O hydrogen bonds to build up the whole molecular packing. The optical properties of this compound were studied by UV–Vis, luminescence spectroscopy and by Time Dependent Density Functional Theory studies. The vibrational properties of this compound were investigated by Infrared and Raman spectroscopy and compared with the calculated ones. The nature and amount of contacts in the crystal packing were investigated by means the Hirshfeld surfaces. Ab-initio and DFT calculations were also performed on whole compound and on reduced model: bis(μ2-chloro)-diaqua-hexachloro-di-bismuth.

    关键词： luminescence,X-Ray diffraction,Vibrational studies,Bismuthates,DFT calculations

    更新于2025-09-23 15:23:52