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Solvothermal Synthesis, Crystal Structure and Luminescent Property of Metal-Organic Frameworks with New Topology Built from Tetrazole Ligand
摘要： A novel two-dimensional (2D) Zn(II) metal-organic frameworks [Zn2(H2bdc)(ATZ)2.5(H2O)·2(H2O)] (1; H2bdc = 1,4-benzenedicarboxylate; ATZ = 5-aminotetrazole) has been solvothermally prepared and structurally characterized by single-crystal X-ray diffraction, which shows that compound 1 crystallized in the orthorhombic space group Pbcm with a = 10.2647(3) ?, b = 26.1194(12) ?, c = 27.3699(13) ?, α = β = γ = 90°, V = 7338.1(5) ?3 and Z = 4. Compound 1 exhibits a layered structure with 3,4-connected new topology, and further stacking of layers leads to a 3D supramolecular framework. The thermalgravimatric behaviour and luminescent properties of 1 have been also investigated. The compound exhibits an intense photoluminescence emissions at 450 nm (λex = 375 nm).
关键词： Tetrazole,Luminescent,Metal-organic frameworks,Crystal structure,Solvothermal
更新于2025-09-11 14:15:04
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Study of indium and antimony incorporation into SnS2 single crystals
摘要： Pure SnS2, 5% In-doped SnS2, 15% In-doped SnS2, 5% Sb-doped SnS2 and 15% Sb-doped SnS2 single crystals are grown in closed sealed quartz ampoule by direct vapour transport technique. The energy dispersive analysis of X-rays analysis of all the five as-grown single crystals showed them to be stoichiometric. The X-ray diffraction analysis showed that all the crystals are single phase possessing a hexagonal structure with (001) preferential orientation. The surface morphology of as-grown single crystals studied by scanning electron microscopy and optical microscopy showed crystal growth is by layer growth mechanism supported by screw dislocation. Selected area electron diffraction showed hexagonal spot pattern confirming the single crystalline nature of the crystals. Optical bandgap of the as-grown crystals determined by UV-Vis-NIR spectroscopy showed that the single crystals possess direct optical bandgap and the value varied between 1.89 and 2.31 eV. The photoluminescence spectra study showed the presence of six peaks. The Raman spectra showed SnS2 type the A1g vibrational mode and shifting in A1g vibrational mode with In and Sb doping. The results are elaborated in details.
关键词： Single crystal growth,Doping,Characterization,Crystal morphology,X-ray diffraction,Crystal structure
更新于2025-09-10 09:29:36
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Experimental study on Nonlinear?Optical property of Ag4P2Se6
摘要： Mid?infrared (MIR) nonlinear optical (NLO) material is critical to laser frequency?conversion technology. Although the main commercial MIR NLO crystals (AgGaS2 AgGaSe2 and ZnGeP2) are practically used, they still have some intrinsic drawbacks, so that it is of great scientific significance to discover new materials with good MIR NLO performances. Among the main systems of chalcogenides to explore MIR NLO crystals, metal thiophosphates and selenophosphates are competitive for their structural diversities and strong covalent P?Q bonds. Here, Ag4P2Se6 (P212121) was selected to evaluate the second(cid:1144)order harmonic generation (SHG) property. As a result, the SHG response with phase?matching ability is about 0.5 times that of AgGaS2 at 2.05 μm in the particle range of 210 ?270 μm, and the laser damage threshold (LDT) is larger than that of AgGaS2. Remarkably, this compound is of low melt temperature of 642 oC with a congruent melting character, also possesses excellent chemical stability, facilitating its further crystal growth and fabrication.
关键词： Nonlinear optical crystal,Ag4P2Se6,Second(cid:1144)order harmonic generation,Crystal structure
更新于2025-09-10 09:29:36
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Hydrothermal synthesis and characterization of In2O3-ZnGa2O4 nanocomposites and their application in IGZO ceramics
摘要： Poly-crystalline In2O3-ZnGa2O4 nanocomposites were successfully synthesized by hydrothermal method with a mixed solution of In, Ga and Zn nitrates with equal mole ratio (In: Ga: Zn=1: 1: 1) and the ammonia was used as the precipitant. The effects of hydrothermal temperature and pH value of the mixed solution on the properties of the nanocomposites were investigated. The microstructure of the prepared In2O3-ZnGa2O4 nanocomposites was characterized by SEM and TEM, respectively. The growth mechanisms of In2O3-ZnGa2O4 nanocomposites were also preliminarily discussed in this study. Results reveal that the IGZO ceramics prepared by In2O3-ZnGa2O4 nanocomposites own a high relative density of 99.5% and low resistivity of 1.2 mΩ·cm, which can be applied to the preparation of IGZO thin film with superior performance.
关键词： Nanocomposites,IGZO,Crystal structure,Ceramics
更新于2025-09-10 09:29:36
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Understanding Crystal Structure and Site Symmetry of Undoped, Eu3+:Ba2LaSbO6 & Eu3+:BaLaMSbO6 (M = Mg,Ca): Tuning Eu-site Occupancy to Develop Both Orange and Red Phosphor
摘要： Double perovskite antimonates of the type BaLaMSbO6 (M=Mg, Ca) were synthesized by standard solid state route. The compounds were characterized by X-ray diffraction and the crystal structure was refined using Rietveld method. BaLaMgSbO6 and BaLaCaSbO6 crystallized in monoclinic (I2/m) and (P21/n) space group respectively. In both the compounds, La occupied A-site of perovskite, which is 12-coordinated as compared to Ba2LaSbO6 where La ion shifts to B-site octahedral coordination due to larger size of Ba as compared to Mg and Ca. The samples were further characterized using FTIR and the frequency of the octahedral vibration is correlated to the electronegativity of the B-site ions. Photoluminescence study of the title compounds and Ba2LaSbO6 was also studied upon doping with 2 atom% Eu3+ ion, which confirmed that Eu3+ occupies distorted 12-coordinated A-site in BaLaMSbO6 (M=Mg, Ca) and symmetrical octahedral B-site in Ba2LaSbO6. Further, the emission spectrum due to each Eu3+ ion at different crystal site was successfully isolated by TRES study. This enables to understand the structural differences of these compounds. This site selective occupancy of Eu3+ ion also has a direct impact on the light emission, which was found to change from orange to red in a dark room in the order Ba2LaSbO6:Eu → BaLaCaSbO6:Eu → BaLaMgSbO6:Eu. Such study will have high impact in designing new commercial Eu3+ ion doped phosphor materials and tailoring of their optical properties.
关键词： Double perovskites,FTIR spectroscopy,Crystal structure,Phosphor material,Antimonates,Photoluminescence (PL)
更新于2025-09-10 09:29:36
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Influence of the growth conditions of LT-AlN on quality of HT-AlN growth on Si (111) by metalorganic chemical vapor deposition
摘要： In this study, AlN films on Si(111) using LT-AlN nucleation layer with various conditions at TMAl preflow were grown and investigated. It was shown that the main factor influencing the quality of AlN films is the degree of the substrate coating by aluminium at preflow. The qualitative model of AlN growth using the LT-AlN nucleation layer for three different coverage by Al (high, optimal and low) was suggested. For the film grown under optimal conditions, the rocking curve FWHM for the AlN (0002) reflection was 0.59о. The demonstrated possibility of the high-quality growth of AlN films below 1000oС would be useful for high power electronics.
关键词： B1. Silicon,B1. Aluminum Nitride,B1. Nitrides,B2. Semiconducting III–V materials,A3. Metalorganic chemical vapor deposition,A1. Crystal structure
更新于2025-09-10 09:29:36
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Two novel Sm(III) complexes with different aromatic carboxylic acid ligands: Synthesis, crystal structures, luminescence and thermal properties
摘要： Two novel Sm(Ⅲ) complexes, [Sm(3,4-DMBA)3(3,4-DMHBA)(5,5′-DM-2,2′-bipy)]2 (1), [Sm(3-MOBA)3(5,5′-DM-2,2′-bipy)]2 (2) (3,4-dimethylbenzoic acid = 3,4-DMHBA, 3-methoxybenzoic acid = 3-MOHBA and 5,5′-dimethyl-2,2′-bipyridine = 5,5′-DM-2,2′-bipy), have been successfully synthesized and assembled. The crystal structures were determined by single crystal X-ray diffraction. Two complexes were characterized by the elemental analysis, IR, powder X-ray diffraction, thermal gravimetric technology. Because of the different ligands, the structures of the two complexes are very different, especially the structure of the complex 1. Each central Sm(Ⅲ) ion of complex 1 was coordinated by three deprotonated 3,4-DMBA-,one unprotonated 3,4-DMHBA and one 5,5′-DM-2,2′-bipy, which has rarely been reported before. However each central Sm(Ⅲ) ion of complex 2 was only coordinated via three deprotonated 3-MOBA- and one 5,5′-DM-2,2′-bipy. In addition, the thermal decomposition mechanism and the three-dimensional infrared accumulation spectra of the evolved gas during the thermal decomposition for two complexes were studied by the simultaneous TG/DSC-FTIR technology. What′s more, the luminescence properties of two complexes were also discussed. Finally, the bacteriostatic activities of two complexes were evaluated against Staphlococcus aureus, Escherichia coli and Candida albicans.
关键词： TG/DSC-FTIR,Crystal structure,Bacteriostatic activities,Lanthanide complexes,luminescence
更新于2025-09-10 09:29:36
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A series of lanthanide coordination polymers based on flexible bis?(imidazole?4,5?dicarboxylate) ligand: Syntheses, structures and fluorescent properties
摘要： A series of lanthanide coordination polymers, namely {[Ln(HL)(H2O)2]·H2O}n (Ln= Ce(1), Pr(2), Nd(3), Eu(4) and Tb(5); H4L = 1,1'-(propane-1,3-diyl)bis(1H-imidazole-4,5-dicarboxylic acid)) have been synthesized under hydrothermal conditions and characterized by infrared spectroscopy, element analysis, single-crystal X-ray diffraction, powder X-ray diffraction and thermogravimetric analyses. These isostructural complexes exhibit a 3D framework with a sra topology built by HL3? anions μ4?bridging metal ions through two IDC groups in different coordination modes. The luminescent property of complexes containing Eu(III) and Tb(III) have also been investigated in detail.
关键词： Lanthanide,Topology,Imidazole-4,5-dicarboxylic acid,Luminescence,Crystal structure
更新于2025-09-10 09:29:36
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Enhanced electrical properties of NaBi modified CaBi2Nb2O9-based Aurivillius piezoceramics via structural distortion
摘要： Two-layer structured ferroelectric ceramics, Ca1-x(NaBi)0.5xBi2Nb2O9 (x = 0.0 - 0.5; CNBN-x), were prepared by solid-state sintering. An artificial pseudo-morphotropic phase boundary was formed by the substitution of Ca with NaBi, and the crystal structure tended to crystallise in the pseudo-tetragonal phase as the increase of NaBi content. Curie temperature (Tc) slightly reduce and remain high value with the increase of NaBi content, which is in the range of 880~935 °C. Moreover, enhanced piezoactivity (d33) and ferroelectricity (Pr) accompanying with decreased dielectric loss can be acquired in NaBi-modified CaBi2Nb2O9. The CNBN-0.1 had the best performance, and its Tc, d33 and Pr was 925 °C, 14.4 pC/N and 6.0 μC/cm2, respectively. Thermal annealing measurement exhibited that the piezoelectric properties of Ca1-x(NaBi)0.5xBi2Nb2O9 had good temperature stability up to 800 °C. Therefore, the NaBi-modified CaBi2Nb2O9 ceramics are perceived to be of promising candidates for high-temperature applications.
关键词： Piezoactivity,Aurivillius piezoceramics,CaBi2Nb2O9,Crystal structure
更新于2025-09-10 09:29:36
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Structural, vibrational and optical properties of an organic-inorganic hybrid crystal of benzyl 4-aminopyridinium tetrabromocadmate(II) based on DFT calculations
摘要： An organic-inorganic hybrid crystal, [Bz-4-NH2Py]2[CdBr4](1) (Bz-4-NH2Py = 1-benzyl-4'-aminopyridinium), was grown successfully by slow evaporation solution growth method at room temperature and characterized. In tetrachlorocadmate(II) dianion, the CdII ion is coordinated by four Br atoms in a close to tetrahedral geometry. The crystal packing is stabilized by C-H···Br hydrogen bonds between [Bz-4-NH2Py]+ cations and [CdBr4]2- anion forming a three-dimensional network. Powder XRD diffraction study confirms the crystalline nature of the title compound. Thermal stability and the gaseous products of decomposition at 362 oC were examined by TG-DTA-MS technique. The Fourier transform infrared (FT-IR) and Raman spectra were recorded and analyzed with the aid of DFT calculations in order to make a suitable assignment of the observed bands. UV-vis spectral analysis was used to determine the band gap energy, and the nonlinear optical (NLO) effect of the compound was predicted using DFT. Further, the title compound exhibits strong fluorescence emission at 394, 329 and 467 nm in the solid at room temperature.
关键词： Nonlinear optical properties,Tetrabromocadmate(II) dianion,Benzyl 4-aminopyridinium,Density functional theory calculation,Crystal structure
更新于2025-09-10 09:29:36