- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
New blue phosphorescence from trifluorosulfonyl-substituted iridium complexes
摘要： For color-pure phosphorescence organic light emitting diodes (PHOLEDs), we synthesized the trifluoromethyl sulfonyl substituted ligand and two new blue Iridium complexes with perfluoro-sulfonyl group (SOCF3pic and SOCF3mpic). The both iridium complexes showed similar photophysical and thermal properties while the HOMO energy leves of two Iridium complexes slightly differnet to be -5.84 eV for SOCF3pic and -5.74 eV for SOCF3mpic, respectively. The device with the SOCF3mpic dopant exhibited higher device efficiencies of 7.17 cd/A and 3.7 % compared to that with the SOCF3pic dopant (4.03 cd/A and 2.78 %). Two-dimensional GIXD images of scattered X-ray intensity from surface to full depth for SOCF3pic-doped and SOCF3mpic-doped TCTA:4PTPS films were characterized for preferential orientation along the out-of-plane direction.
关键词： preferential orientation along the out-of-plane direction,blue phosphorescence,iridium complex,grazing incidence wide-angle X-ray diffraction,organic light emitting diodes
更新于2025-09-23 15:23:52
-
Effects of Ge substrate on the structural and optical conductivity parameters of Bi2O3 thin films
摘要： In this article the structural, optical and dielectric properties of a 200 nm thick Bi2O3 thin films which are deposited onto amorphous germanium substrate are reported. Both of the Ge and Bi2O3 thin films are prepared by the thermal evaporation technique under vacuum pressure of 10^-5 mbar. Bi2O3 thin films are found to prefer the monoclinic nature of structure with larger values of microstrain, dislocation density, stacking faults and smaller grain sizes upon replacement of the glass substrate by germanium. Optically, significant redshift in the energy band gap is observed when the films are grown onto Ge. The Ge/Bi2O3 heterojunctions exhibit a conduction and valence band offsets of value of 0.81 and 1.38 eV, respectively. In addition to the enhancement in the dielectric constant near the IR region, the Drude-Lorentz modeling of the Ge/Bi2O3 heterojunctions has shown remarkable effect of the Ge substrate on the optical conductivity parameters of Bi2O3. Particularly, the drift mobility increased by about one order of magnitude, the free hole density decreased by ~24 times and the plasmon frequency ranges extended from 5.21 to 11.0 GHz to 2.59–12.80 GHz when germanium substrate is used. The optical features of the heterojunction nominate it for visible light communication technology.
关键词： Ge/Bi2O3,Band offsets,X-ray,Heterojunction,Plasmon,Dielectric
更新于2025-09-23 15:23:52
-
Photocatalytic oxidation of aromatic alcohols over silver supported on cobalt oxide nanostructured catalyst
摘要： In this paper, we report an in-situ synthesis of silver supported on cobalt oxide (Ag/Co3O4) nanoparticles (NPs) and studied the catalytic activity of this material as an eco-friendly, simple, recyclable and efficient catalyst for one‐pot photocatalytic oxidation of aromatic alcohols. Ag nanoparticles with the sizes of 2–5 nm supported on spherical Co3O4 with the radius between 40 and 60 nm were synthesized by homogeneous chemical precipitation followed by hydrothermal heating. The as-synthesized catalyst was thoroughly characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), elemental mapping, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and N2 adsorption-desorption isotherm (BET) analysis. It was observed that the catalysts with 1 wt% of silver loading shows high activity and selectivity toward the target aldehyde product. The effects of different reaction parameters such as reaction time, oxidant and solvent were investigated and studied in detail. The synergistic effect between the surface Ag NPs and Co3O4 nanospheres plays a vital role toward very high catalytic activity.
关键词： Oxide materials,Chemical synthesis,Catalysis,X-ray diffraction
更新于2025-09-23 15:23:52
-
Crystal growth and characterization of γ-glycine grown from AgSO4 for nonlinear optical applications
摘要： In the present work 0.1 M to 0.5 M proportions of silver sulphate (AgSO4) added glycine single crystals were grown by slow solvent evaporation method. The Powder XRD study confirms that the grown crystals have γ-glycine crystal structure and it crystallizes into a hexagonal structure with a non-centrosymmetric space group of P31. The dielectric constant and dielectric loss of grown crystal was carried out as a function of frequency and the results were discussed. The positive photoconducting nature of the grown crystals was studied by the photoconductivity study. Second harmonic generation (SHG) efficiency of the grown γ-glycine crystal was assessed by using Nd: YAG laser. The results confirms that the grown crystals have higher efficiency compared to the reference (KDP) crystal.
关键词： B2. Dielectric Materials,A1. X-ray diffraction,A1. Crystal structure,B2. Nonlinear optic materials
更新于2025-09-23 15:23:52
-
Tailoring lattices of Bi2WO6 crystals via Ce doping to improve the shielding properties against low-energy gamma rays
摘要： In this study, lattices of Bi2WO6 crystals were tuned by cerium doping in a hydrothermal process in order to enhance the shielding properties against low-energy gamma rays. The products obtained were characterized by Raman, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy techniques. The results demonstrated that cerium ions were successfully introduced into the lattices of the Bi2WO6 crystals and they partially replaced the bismuth ion sites. The shielding results showed that 10 mol% cerium doping allowed the Ce-doped Bi2WO6 crystals to shield against 59.5 keV gamma rays at a 49.41% better level compared with the original crystals. The enhanced shielding against low-energy gamma rays was ascribed to the expanded K-edge absorbing area of bismuth after cerium doping. In this study, we developed a facile synthetic method for obtaining Ce-doped Bi2WO6 materials. Importantly, these crystals could be used as functional fillers in rubber composites to prepare wearable products (such as clothing) with desirable shielding properties and no requirement for lead.
关键词： Bismuth tungstate,Gamma ray shielding,Cerium doping
更新于2025-09-23 15:23:52
-
Second-generation motion correction algorithm improves diagnostic accuracy of single-beat coronary CT angiography in patients with increased heart rate
摘要： Objective To assess the effect of a second-generation motion correction algorithm on the diagnostic accuracy of coronary computed tomography angiography (CCTA) using a 256-detector row CT in patients with increased heart rates. Methods Eighty-one consecutive symptomatic cardiac patients with increased heart rates (≥ 75 beats per min) were enrolled. All patients underwent CCTA and invasive coronary angiography (ICA). CCTA was performed with a 256-detector row CT using prospectively ECG-triggered single-beat protocol. Images were reconstructed using standard (STD) algorithm, first-generation intra-cycle motion correction (MC1) algorithm, and second-generation intra-cycle motion correction (MC2) algorithm. The image quality of coronary artery segments was assessed by two experienced radiologists using a 4-point scale (1: non-diagnostic and 4: excellent), according to the 18-segment model. Diagnostic performance for segments with significant lumen stenosis (≥ 50%) was compared between STD, MC1, and MC2 by using ICA as the reference standard. Results The mean effective dose of CCTA was 1.0 mSv. On per-segment level, the overall image quality score and interpretability were improved to 3.56 ± 0.63 and 99.2% due to the use of MC2, as compared to 2.81 ± 0.85 and 92.5% with STD and 3.21 ± 0.79 and 97.2% with MC1. On per-segment level, compared to STD and MC1, MC2 improved the sensitivity (92.2% vs. 79.2%, 80.7%), specificity (97.8% vs. 82.1%, 90.8%), positive predictive value (89.9% vs. 48.4%, 65.1%), negative predictive value (98.3% vs. 94.9%, 95.7%), and diagnostic accuracy (96.8% vs. 81.5%, 89.0%). Conclusion A second-generation intra-cycle motion correction algorithm for single-beat CCTA significantly improves image quality and diagnostic accuracy in patients with increased heart rate.
关键词： Coronary angiography,Heart rate,Tomography, X-ray computed,Coronary vessels,Motion
更新于2025-09-23 15:23:52
-
An unstructured Monte Carlo ray-tracing method for solving radiative heat transfer in 3D gray semitransparent medium
摘要： Monte Carlo ray-tracing method (MCRTM) is widely used for solving the Radiative Transfer equation (RTE) due to its high accuracy and flexibility. In this paper, a MCRTM is developed for solving the radiative heat transfer in gray semitransparent media with complex geometries which are discretized by 3D unstructured grids. A novel algorithm associated to unstructured four-node tetrahedron element is proposed for generating random emitting positions of rays, and the ray tracing process is performed based on Beer's law. Meanwhile, radiation distribution factors are used for calculating radiative source terms which are loaded to the grid. The present method is first validated by comparing the predictive results with those from previous studies on a cubic enclosure, a 3D L-shaped enclosure, and a 3D elliptical enclosure, respectively. Furthermore, a radiation-conduction heat transfer problem is examined in a cylindrical enclosure. All the comparisons show that the present method is in good agreement with these previous cases. This method can be well adapted to various complex geometries. In addition, since the source term is calculated by the radiation distribution factor, which can be reused for different conditions as long as the volumetric radiative properties remain unchanged, this will bring great advantage when coupled with other heat transfer models such as conduction, convection, combustion, etc.
关键词： Monte Carlo ray-tracing method,Radiative heat transfer,Semitransparent medium,Radiation distribution factor,Unstructured grids
更新于2025-09-23 15:23:52
-
Structural and conduction behaviour of (BaSr)0.5TiO3 modified in BFO perovskite
摘要： The multiferroic ceramic (BiBa0.5Sr0.5)0.5 (Fe0.5Ti0.5) O3 (BFO-BST) is prepared in an economic way by conventional solid state reaction route and its different behaviours are studied and reported. The X-Ray diffraction (XRD) and Scanning Electron Microscope (SEM) investigations have confirmed single phase forming by the compound. Full proof reitveld analysis has been used for structural refinement. XRD pattern of the sample it is inferred that the observed peaks and calculated peaks are well matched with each other having minimum deviation. The density of the compound is quiet high as calculated by above analysis as well as from SEM image. Dielectric behaviour of the compound has been analyzed through the variation of dielectric constant with frequency while the electrical behaviour is studied through the complex impedance and modulus analysis. Additionally, verification of Jonscher's power law from ac conductivity study gives the detail findings about electrical behaviour of the material.
关键词： Modulus,Ceramic,X-ray diffraction,Impedance
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
-
Structural, optical, electrical and thermal characteristics of La{CS(NH2)2CO(NH2)2}Cl3 : A novel hybrid complex for optoelectronic applications
摘要： A hybrid complex of lanthanum chloride with urea and thiourea is crystallized at room temperature by conventional solution method. The structural investigations by single crystal X-ray diffraction confirmed the orthorhombic system with cell dimensions a = 7.676 ?, b = 8.564 ?, c = 5.498 ?, α = β = γ = 90°. The optical studies by UV–VIS absorption spectroscopy shows the complex exhibits transmittance about 96%. The complex is characterized as the wide band gap crystals with value greater than 4 eV. The dielectric properties were studied in frequency range 10 kHz–1 MHz in temperature range 303–453 K. The ac conductivity was found to obey the universal power law and suggests the correlated barrier hoping mechanism dominating the conduction process. The thermal stability and the decomposition mechanism were confirmed by thermo gravimetric and differential thermo analytical (TG/DTA) techniques.
关键词： Dielectric analysis,ac conductivity,Hybrid complex,X-ray diffraction,UV–Vis spectrum
更新于2025-09-23 15:23:52