- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Optical and Magnetic Properties of Cobalt Ions Doped Calcium Phosphate by Ultrasonication
摘要： Background: Hydroxyapatite (HAp) is a remarkable member of the calcium phosphate family. It resembles natural bone in both structure and chemical composition. Owing to its bioactive and chemical properties, it has been used as a biocompatible osteogenesis and energy materials as discussed in patents. Objective: To study the structural, optical properties and magnetic properties of hydroxyapatite and cobalt ions doped hydroxyapatite for biomedical application. Method: Hydroxyapatite and cobalt ions doped hydroxyapatite were synthesized by ultrasonication assisted wet chemical synthesis. Results: X-ray diffraction analysis confirmed the phase and crystallite size of hydroxyapatite. There was a 12% decrease in crystallite size compared to pristine. The functional groups and vibrational assignments of the samples were observed in infra-red and Raman spectra. Optical properties of the samples were analyzed by Diffuse Reflectance Spectroscopy, ultraviolet-visible and photoluminescence emission spectroscopy. Doped samples showed paramagnetic in nature. Conclusion: Therefore, the cobalt doped samples could be employed in biomedical applications.
关键词： optical,luminescence,hyperthermia,bioceramics,Cobalt ions,magnetic,hydroxyapatite
更新于2025-09-23 15:23:52
-
Circularly Polarized Luminescence from Chiral Conjugated Poly(carbazole-ran-acridine)s with Aggregation-Induced Emission and Delayed Fluorescence
摘要： Pure organic materials with circularly polarized luminescence (CPL) and delayed fluorescence have gained increasing interest from academic and technological areas. To enhance the solid-state emission and exciton utilization in chiral optoelectronic devices, a synthetic strategy to impart conjugated polymers with CPL and aggregation-induced delayed fluorescence was proposed. Herein, two conjugated macromolecules with electron-donating poly(carbazole-ran-acridine) backbones, electron-withdrawing dibenzothiophen-2-yl(phenyl)methanone and chiral alanine moieties were designed and synthesized. Their neat films exhibited strong green emission with quantum yields of 6.7% and 10.3% and delayed fluorescence with lifetime of 1.358 μs and 1.366 μs, respectively. Both Cotton effect and CPL with dissymmetry factor of –2.01 × 10–3 and –1.39 × 10–3 were determined in the solid state. Such unique conjugated polymers were employed as solution-processed emitting layers in organic light emitting diodes, which displayed maximum brightness of 1477 cd/m2 and maximum current efficiency of 2.52 cd/A.
关键词： OLEDs,conjugated polymers,aggregation-induced emission,delayed fluorescence,aggregation-induced delayed fluorescence,circularly polarized luminescence
更新于2025-09-23 15:23:52
-
Synthesis of Fluorescent Ag Nanoclusters for Sensing and Imaging Applications
摘要： Metal nanoparticles have attracted more and more attention in the last years due to their unique chemical and physical properties which are very different from the metal bulk material. In particular, when the size of nanoparticles decreases below two nm, nanoparticles can be described as nanoclusters (NCs), and they present peculiar optical properties. The excited electrons in addition to specific absorption bands show also a bright luminescence related to the quantum size effect which produce discrete energy levels. Optical properties (absorption and fluorescence) of these NCs are widely used in many different applications in science and engineering, such as chemical sensors, fluorescent probes for bio imaging or in environmental issues. In the present study, we report on the synthesis of silver nanoclusters (AgNCs) in aqueous phase using silver nitrate as precursor salt and L-Glutathione (GSH) as stabilizer. AgNCs were characterized using absorption and fluorescence spectroscopy, and transmission electron microscopy (TEM). The strong absorption and luminescence shown by these NCs are very promising for a possible exploitation both as label for bioimaging and for optical sensors for heavy metal ions.
关键词： luminescence,spectroscopy,GSH-Ag Nanoclusters,optical absorption
更新于2025-09-23 15:23:52
-
Electronic structure and luminescent properties of Ce3+-doped Ba3Lu2B6O15, a high-efficient blue-emitting phosphor
摘要： A high-e?cient blue-emitting phosphor Ba3Lu2B6O15: Ce3+ was synthesized by three-step solid-state method. XRD Rietveld re?nement analysis reveals that Ba3Lu2B6O15 is of cubic Ia3(——) system, owning a high-symmetric layer structure with two regular LuO6 octahedrons and one BaO9 polyhedron. Density functional theory (DFT) calculation result indicates BLB is a kind of direct band-gap material with broad band-gap of ~5.10 eV. Ba3Lu2B6O15:Ce3+ phosphor exhibits a bright blue emission under UV excitation with high quantum e?ciency of > 90%, and the possible reasons are discussed basing on structural and spectral data. Because of its excellent luminescent properties, Ba3Lu2B6O15:Ce3+ could be a promising candidate as a blue phosphor for NUV LED devices.
关键词： Ce3+,Luminescence,Phosphor,Structure
更新于2025-09-23 15:23:52
-
Light-induced effects on crystal size and photo-stability of colloidal CsPbBr<sub>3</sub> perovskite nanocrystals
摘要： CsPbBr3 perovskite nanocrystals (PNCs) have been synthesized using the hot injection method. The CsPbBr3 PNCs exhibit a high photoluminescence quantum yield (PLQY) of 73%. A comprehensive study of UV light interaction with the CsPbBr3 PNCs was performed. SEM images, photoluminescence spectra, X-Ray Diffraction and PLQY measurements were obtained for different time of UV exposure. The exposure to UV light modifies the crystal size (from 10X10 nm to 12X95 nm) and morphology (change from nanocubic to nanorods form). The XRD spectra show a change from tetragonal to cubic crystalline structure. In addition, the interaction of UV light modifies the optical properties of the PNCs by varying the photoluminescence. The material remains stable for a period of 1 hour, however, with exposure to UV light, the PNCs show a decrement in QY from 73.3% to 46.6% after 30 days. These results indicate that light-induce variation in morphological and photo-stability of CsPbBr3 PNCs.
关键词： luminescence,photostability,CsPbBr3 nanocrystals,morphological study
更新于2025-09-23 15:23:52
-
Low temperature thermochronology using thermoluminescence signals from K-feldspar
摘要： Thermoluminescence (TL) and isothermal thermoluminescence (ITL) signals from K-feldspar were studied. The signals from K-feldspar have provided multiple thermometers for thermochronological study. Protocols of multiple aliquot (MA) additive-dose (A) and regenerative-dose (R) have been applied and tested for equivalent dose (De) determinations using TL and ITL signals (MAA-TL, MAR-TL, MAA-ITL and MAR-ITL). Single aliquot regenerative-dose (SAR) protocol was only applied for De determination using ITL signals (SAR-ITL). A 50–60°C translation of heating temperature was necessary for the ITL De values to agree with TL De values. Based on the experiment results and merits-drawbacks comparison of the five tested protocols, the MAR-TL and SAR-ITL are favorable because of their efficiency and accuracy in De determinations. These two protocols were further applied to the samples from the Nujiang River valley and both explicitly demonstrated the thermal history of the samples. They are suitable for K-feldspar thermochronology study. They, as a parallelism of the previous studies of quartz TL and ITL signals, can provide multiple measures for a rock sample with the same thermal history in geo-thermochronological studies.
关键词： luminescence signals,K-feldspar,thermochronology,protocol
更新于2025-09-23 15:23:52
-
Impurity induced cross luminescence in KMgCl3 : An ab-initio study
摘要： Density functional theory calculations have been carried out to calculate the electronic structure and optical properties of host and Cs doped KMgCl3. All the calculations were performed by using the Tran and Blaha modified Becke-Johnson potential (TB-mBJ) in order to accurately predict the band gap and the optical spectra. The investigated compound is found to be an insulator with direct band gap of 4.7, 6.9 eV using Generalized Gradient Approximation (GGA), and TB-mBJ functionals respectively. The calculated refractive index shows the optical isotropy of this compound in the low energy region, though the structure is anisotropic. From our theoretical calculations we predict KMgCl3 doped with Cs to be a better cross luminescence material compared to host compound, where additional Cs states are present below the valence band of the compound. Detailed discussion is presented in the manuscript.
关键词： Scintillators,Cross luminescence,Optical properties,Electronic structure
更新于2025-09-23 15:23:52
-
Bi-functional heater-thermometer Nd3+-doped nanoparticles with multiple temperature sensing parameters
摘要： Achieving a combination of real-time diagnosis and therapy in a single platform with sensitive thermometry and efficient heat production is a crucial step towards controllable photo-thermal therapy. Here, Nd3+-doped Y2O3 nanoparticles prepared by combined Pechini-foaming technique operating in first and second biological windows were demonstrated as thermal sensors within wide temperature range of 123–873 K and heaters with temperature increase by 100 K. Thermal sensing was performed based on various approaches: luminescence intensity ratio (electronic levels; Stark sublevels), spectral line position and line bandwidth were used as temperature dependent parameters. Applicability of regarded sensing parameters along with relative thermal sensitivity and temperature resolution were discussed and compared. Influence of Nd3+ doping concentration on thermometer and heater efficiency was also investigated.
关键词： Nanosensor,Biological window,Hyperthermia,Luminescence,Thermometry,Nd3+
更新于2025-09-23 15:23:52
-
Scintillation properties of Ce-doped Yb3Al5O12 single crystals
摘要： Yb3Al5O12 (YbAG) single crystals were prepared by the Floating Zone (FZ) method with and without doping with different concentrations of Ce, and then we evaluated their basic scintillation properties. All the samples showed scintillation with emission peaks in the range from 300 nm to 600 nm. The origin of this emission peak was attributed to the charge transfer luminescence of Yb3+. In addition, the Ce-doped samples showed three strong emission bands, in which the emission origin is also predominantly due to the charge transfer emission but the spectrum was deformed due to a self-absorption by the 4f-5d transitions of Ce3+. Scintillation decay profiles of all the samples were approximated by a sum of two exponential decay functions, and the obtained decay times were 1 and 9-10 ns. Among the present samples, the 0.5% Ce-doped sample showed the lowest scintillation afterglow level. All the samples demonstrated a full energy peak in the pulse height spectrum measured under 241Am 5.5 MeV α-ray irradiation. Among the present samples, the undoped sample showed the highest light yield with a value of 20 ph/5.5MeV-α.
关键词： Ce3+,Charge transfer luminescence,Garnet,Scintillation
更新于2025-09-23 15:23:52
-
Photoluminescence of partially reduced Eu2+/Eu3+ active centers in a NaF–Al2O3–P2O5 glassy matrix with tunable smooth spectra
摘要： In this work, a series of photoluminescent materials have been synthesized based on optically transparent and chemically stable glasses of the nominal composition Na3Al2(PO4)2F3 (NaF–Al2O3–P2O5 system) doped with 1 wt % of europium. It has been shown that the synthesis conditions (mainly the temperature and duration of the melting stage under reducing conditions) strongly affected the photoluminescence spectra of the material. This effect has been ascribed to varying proportions between Eu3+ and Eu2+ ions concentrations, imposed by the synthesis conditions, which was confirmed by XPS, absorption and decay times measurements. As both Eu3+ and Eu2+ centers exhibit photoluminescence in different ranges of the visible spectra (Eu3+ – red, and Eu2+ – mainly blue) the possibility, shown by us, to control relative proportions of the oxidation states of europium and consequently to control the photoluminescence spectra, may be advantageous from the viewpoint of potential applications of such materials as novel phosphors for white LEDs with the emission spectra resembling natural light.
关键词： glassy matrix,europium facile reduction,scalable synthesis,tunable luminescence
更新于2025-09-23 15:23:52