Design and Optical Properties of Rare Earth-Based Mixed-Anions (O, S, F) Compounds

2002 ◽  
Vol 755 ◽  
Author(s):  
Damien Pauwels ◽  
Alain Demourgues ◽  
Alain Tressaud
Keyword(s):  
Optical Properties ◽  
Rare Earth ◽  
Solid State ◽  
Visible Absorption ◽  
X Ray ◽  
Solid State Route ◽  
Earth Environment ◽  
Fluorite Type ◽  
Uv Visible ◽  
Single Crystal Analysis

ABSTRACTRare earth-based mixed-anions (O, S, F) compounds have been prepared by solid state route. The structures have been determined on the basis of powder diffraction (X-ray/neutrons) refinement and/or single crystal analysis. They have been described as a stacking of [Sx] 2x- layers and fluorite type blocks. The evaluation of the rare earth environment (bondlength, number of neighbors) can be directly related to the bandgap and to the UV-visible absorption in the La-based compounds.

Influence of Organic Polymers as Capping Agent on Structural and Optical Properties of ZnS:Mn2+ and CdS Nanocrystals

2008 ◽  
Vol 8 (1) ◽  
pp. 301-308 ◽  
Author(s):  
Ashish K. Keshari ◽  
M. Kumar ◽  
Prashant K. Singh ◽  
Avinash C. Pandey
Keyword(s):  
Optical Properties ◽  
Photo Luminescence ◽  
Organic Polymers ◽  
Visible Absorption ◽  
Capping Agents ◽  
X Ray ◽  
Cds Nanocrystals ◽  
Uv Visible ◽  
Organic Capping ◽  
Co Precipitation

We have synthesized the luminescent ZnS:Mn2+ and bare CdS nanocrystals by employing polyvinyl alcohol (PVA), citric acid (CA) and biotin as organic capping agents by chemical co-precipitation route. The synthesized materials were characterized by X-ray diffraction, small angle X-ray scattering and transmission electron microscopy for the structural analysis, while UV-Visible spectroscopy and photoluminescence (PL) for optical properties. The results show that all the three organic polymers have the same effect and are capable of controlling the growth of the nanoclusters. From UV-Visible absorption spectra, it was observed that different capping agents do not affect the band gap of ZnS:Mn2+ system as well, while capping effect clearly observed on PL properties of ZnS:Mn2+ system. We have observed a novel result that capping with biotin show excellent photo-luminescence as compared to capping of PVA and CA on ZnS:Mn2+-systems. On the other hand, the annealing of these systems leads to degradation of luminescence intensity.

Optical Properties of Ba2-XSrxSiO4: Eu2+, Dy3+ Phosphors and their Applications for White LED

2012 ◽  
Vol 529 ◽  
pp. 154-158
Author(s):  
Mei Zhang ◽  
Ping Wang ◽  
Xin He ◽  
Qing Guang Zeng ◽  
Jin Xiu Wen
Keyword(s):  
Solid Solution ◽  
Optical Properties ◽  
High Temperature ◽  
Solid State ◽  
Solid State Lighting ◽  
White Led ◽  
Excitation Spectra ◽  
X Ray ◽  
Powder Samples ◽  
Uv Visible

A series of Ba1.91-xSrxSiO4:Eu2+, Dy3+phosphors were synthesized by the high-temperature solid-state reaction. The structure of powder samples were characterized by X-ray powder diffraction. The photoluminescence emission and excitation spectra are also studied. It can be proved the formation of the solid solution of Ba1.91-xSrxSiO4:Eu2+, Dy3+ compounds, and the phosphors can be efficiently excited by UV-visible light from 300 to 480 nm. The as-synthesized Ba1.91-xSrxSiO4:Eu2+, Dy3+ phosphors are promising candidates applicable to near-UV and blue LEDs for solid-state lighting.

EFFECT OF RAPID THERMAL ANNEALING ON MICROSTRUCTURE AND OPTICAL PROPERTIES OF ZnO NANORODS

2011 ◽  
Vol 10 (01n02) ◽  
pp. 65-68 ◽  
Author(s):  
R. CHAKRABORTY ◽  
SOUMEN DHARA ◽  
P. K. GIRI
Keyword(s):  
Optical Properties ◽  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Zno Nanorods ◽  
Mechanochemical Reaction ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Pl Spectra ◽  
Uv Visible

In this work, we have investigated the influence of rapid thermal annealing (RTA) on structural and optical properties of ZnO nanorods synthesized by a mechanochemical reaction route using a planetary ball mill for different reaction time durations. Optical properties of as-grown and RTA-annealed samples are studied by UV–visible absorption and photoluminescence (PL), while structural studies are performed using X-ray diffraction line profile analysis and transmission electron microscopy. X-ray diffraction pattern of each sample is accompanied by characteristic wurtzite peaks of zinc oxide and exhibits the decrease in full width half maxima of the peaks after RTA. Williamson–Hall plot of each pattern is done to correlate the effect of strain of as-synthesized and RTA-treated samples. UV–visible absorption spectra show distinct redshift of excitonic absorption peaks with respect to those of as-synthesized samples. Interestingly, in PL spectra, the broad visible emission peaks observed for as-synthesized samples are eliminated completely for annealed samples. However, some of the constituent peaks in the UV–blue region of the PL spectra redshifted due to the grain growth and strain reduction.

scholarly journals Optical properties for TiO2 / PMMA nanocomposite thin films prepared by plasma jet

2018 ◽  
Vol 15 (35) ◽  
pp. 24-28
Author(s):  
Saba J. Kadhem
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Titanium Oxide ◽  
Absorption Spectra ◽  
Plasma Jet ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Nanocomposite Thin Films ◽  
Uv Visible

PMMA/TiO2 homogeneous thin films were deposited by using plasma jet system under normal atmospheric pressure and room temperature. PMMA/TiO2 nanocomposite thin film synthesized by plasma polymerization. Titanium oxide was mixed with Methyl Methacrylate Monomer (MMA) with specific weight ratios (1, 3 and 5 grams of TiO2 per 100 ml of MMA). Optical properties of PMMA/TiO2 nanocomposite thin films were characterized by UV-Visible absorption spectra using a double beam UV-Vis-NIR Spectrophotometer. The thin films surface morphological analysis is carried out by employing SEM. The structure analysis are achieved by X-ray diffraction. UV-Visible absorption spectra shows that the increasing the concentration of titanium oxide added to the polymer leads to shift the peak position (λmax) toward the infrared region of the electromagnetic spectrum. Also the peak width increases when the concentration of TiO2 increases. It can be controlled optical energy band gap of PMMA/TiO2 nanocomposite thin films by changing concentration of TiO2. SEM indicate a uniform distribution of titanium oxide particles in PMMA matrix. The x-ray diffraction pattern indicated that the thin films have amorphous structure.

scholarly journals Synthesis, Characterization and Pressure Effect on Structural and Mechanical Properties of MgBi2O6: Solid-State Route and DFT Study

2020 ◽  
pp. 71-86
Keyword(s):  
Mechanical Properties ◽  
Optical Properties ◽  
Solid State ◽  
Band Structure ◽  
Band Gap ◽  
Structure Analysis ◽  
Solid State Route ◽  
Tetragonal Crystal ◽  
Small Band ◽  
Uv Visible

Here we have prepared good quality crystalline sample MgBi2O6 employing the solid-state reaction technique. The synthesized material was characterized by XRD and SEM (scanning electron microscopy). The structural study confirmed that MgBi2O6 possesses a tetragonal crystal configuration (JCPDS PDF#, No. 86-2492) with outstanding crystallinity and a grain size between 200 to 350 nm. The temperature dependence electrical resistivity and conductivity were measured by two probe methods and ensured the semiconducting nature of this material. Using the impedance analyzer and UV-visible spectrophotometer we studied the experimental electronic and optical properties of this material. To explore the hypothetical features of MgBi2O6 we have used first-principles methods that depend on CASTEP code. The band structure analysis also ensured the semiconducting nature of MgBi2O6 with a small band gap of 0.12 eV. The semiconducting behavior of MgBi2O6 with a band gap of 0.12 eV was also observed by the band structure analysis. The Born’s stability criteria were fulfilled by the investigated elastic constants and ensured the stable nature of MgBi2O6. The response of structural and mechanical properties with the pressure of MgBi2O6 was discussed in detail. We have also studied the hypothetical optical properties of MgBi2O6 by CASTEP code.

scholarly journals Phytosynthetic Fabrication of Lanthanum Ion-Doped Nickel Oxide Nanoparticles Using Sesbania grandiflora Leaf Extract and Their Anti-Microbial Properties

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 124
Author(s):  
Srihasam Saiganesh ◽  
Thyagarajan Krishnan ◽  
Golla Narasimha ◽  
Hesham S. Almoallim ◽  
Sulaiman Ali Alhari ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Optical Properties ◽  
Rare Earth ◽  
Nickel Oxide ◽  
Photoelectron Spectroscopy ◽  
Metal Oxide Nanoparticles ◽  
Oxide Nanoparticles ◽  
Nio Nanoparticles ◽  
X Ray ◽  
Sesbania Grandiflora

Over the past few years, the photogenic fabrication of metal oxide nanoparticles has attracted considerable attention, owing to the simple, eco-friendly, and non-toxic procedure. Herein, we fabricated NiO nanoparticles and altered their optical properties by doping with a rare earth element (lanthanum) using Sesbania grandiflora broth for antibacterial applications. The doping of lanthanum with NiO was systematically studied. The optical properties of the prepared nanomaterials were investigated through UV-Vis diffuse reflectance spectra (UV-DRS) analysis, and their structures were studied using X-ray diffraction analysis. The morphological features of the prepared nanomaterials were examined by scanning electron microscopy and transmission electron microscopy, their elemental structure was analyzed by energy-dispersive X-ray spectral analysis, and their oxidation states were analyzed by X-ray photoelectron spectroscopy. Furthermore, the antibacterial action of NiO and La-doped NiO nanoparticles was studied by the zone of inhibition method for Gram-negative and Gram-positive bacterial strains such as Escherichia coli and Bacillus sublitis. It was evident from the obtained results that the optimized compound NiOLa-04 performed better than the other prepared compounds. To the best of our knowledge, this is the first report on the phytosynthetic fabrication of rare-earth ion Lanthanum (La3+)-doped Nickel Oxide (NiO) nanoparticles and their anti-microbial studies.

Synthesis and Characterizations of Nanocubes, Monodispersed Nanocrystals and Nanospheres of Au

2007 ◽  
Vol 353-358 ◽  
pp. 2163-2166
Author(s):  
Ming Yang ◽  
Guo Qing Zhou ◽  
Jiang Guo Zhao ◽  
Zhan Jun Li
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Powder Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Transmission Electron ◽  
Uv Visible ◽  
Scherrer Formula ◽  
Visible Absorption Spectroscopy

Nanocubes, monodispersed nanocrystals and nanospheres of Au have been prepared by a simple reaction between HAuCl4·4H2O, NaOH and NH2OH·HCl in the presence of gelatin. The role of gelatin and the affection of pH in producing the nanoparticles of Au were discussed. The products were characterized by X-ray powder diffraction, transmission electron microscopy, and UV-visible absorption spectroscopy. The sizes of the monodispersed nanocrystals of Au were estimated by Debye-Scherrer formula according to XRD spectrum.

Photoactive amphiphiles for the assembly of supramolecular architectures

2015 ◽  
Vol 185 ◽  
pp. 471-479 ◽  
Author(s):  
B. P. Jarman ◽  
F. Cucinotta
Keyword(s):  
Visible Spectrum ◽  
Solid Materials ◽  
Visible Absorption ◽  
Optical Components ◽  
Absorption And Emission ◽  
X Ray ◽  
Supramolecular Architectures ◽  
Uv Visible ◽  
Absorption And Emission Spectroscopy ◽  
Molecular Organisation

The presented study reports the use of photoactive templating structures for the design of porous frameworks with built-in optical functionalities. The materials have been synthesised and characterised using powder X-ray diffractometry, UV-visible absorption and emission spectroscopy. The latter shows that, by varying the relative amount of an amphiphilic chromophore in the micellar templates, it is possible to tune the light absorption and emission properties over the visible spectrum, by means of controlling the molecular organisation and the excitonic coupling of aggregated species. This enables versatile solid materials that can be used as optical components for light-harvesting and converting systems to be obtained .

Syntheses and crystal structures of guanidine hydrochlorides with two Schiff base functions as efficient colorimetric and selective sensors for fluoride

2018 ◽  
Vol 73 (8) ◽  
pp. 601-609 ◽  
Author(s):  
Bei Wang ◽  
Pei-Zhi Zhang ◽  
Xin Chen ◽  
Ai-Quan Jia ◽  
Qian-Feng Zhang
Keyword(s):  
Optical Properties ◽  
Schiff Base ◽  
Molecular Structures ◽  
X Ray Diffraction ◽  
Guanidinium Chloride ◽  
Visible Absorption ◽  
X Ray ◽  
Color Changes ◽  
Base Functions ◽  
Magnetic Resonances

AbstractA series of guanidinium chloride derivatives have been synthesized by condensation of 1,3-diaminoguanidine monohydrochloride with heteroaromatic formaldehydes in good yields. All compounds were characterized by nuclear magnetic resonances and infrared spectroscopies, and the molecular structures of four compounds were determined by single crystal X-ray diffraction. The optical properties of these guanidinium chloride derivatives with fluoride anions were investigated, showing selective color changes from colorless to yellow or orange, red-shifted in the ultraviolet/visible absorption spectra.

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