Synthesis of alloyed Bi2TexSe(3-x) nanoparticles and thermoelectric characterization of bulk nanostructured materials obtained by their assembly

2015 ◽  
Vol 1804 ◽  
pp. 1-6 ◽  
Author(s):  
Romain Bude ◽  
Laurent Divay ◽  
Renato Bisaro ◽  
Bernard Servet ◽  
Elodie Leveugle ◽  
...  
Keyword(s):  
Careful Study ◽  
Selenium Content ◽  
X Ray Diffraction ◽  
Synthesis Conditions ◽  
Simultaneous Control ◽  
Solution Route ◽  
Diffraction Peaks ◽  
The Difference ◽  
Low Selenium

ABSTRACTThe optimization of the figure of merit of thermoelectric materials requires the simultaneous control of the material composition and microstructure. Assembly of nanoparticles obtained by a solution route is an attractive bulk fabrication method because size and shape of the nanoparticles can be tuned by variation of the synthesis conditions. Recently, new synthetic pathways were reported among which reducing agent assisted, surfactant free processes. We report here the evaluation of this method for the synthesis of Bi2TexSe3-x alloyed nanoparticles with varying selenium concentrations. X-ray diffraction studies conducted on powder and pellet samples show that two alloyed phases are present in the sample even at low selenium content. The careful study of the position of the diffraction peaks as function of the formulation shows that this behaviour could arise from the difference in reactivity of selenium and tellurium. Moreover, the electrical conductivity of the samples is shown to increase upon selenium addition while the Seebeck coefficient is reduced. Power factor shows an optimum value around 20% selenium content with a large tolerance in composition.

Relation between Magnetic, Spectroscopic and Structural Properties of Binuclear Copper(II) Complexes of Pentadentate Schiff-base Ligand, Semi-empirical and ab-initio Calculations

2003 ◽  
Vol 58 (5-6) ◽  
pp. 363-372 ◽  
Author(s):  
Y. Elerman ◽  
H. Kara ◽  
A. Elmali
Keyword(s):  
Ab Initio ◽  
Coupling Constants ◽  
Antiferromagnetic Coupling ◽  
X Ray Diffraction ◽  
Hartree Fock ◽  
Ligand Orbital ◽  
Rhf Calculations ◽  
The Difference ◽  
Semi Empirical

The synthesis and characterization of [Cu2(L1)(3,5 prz)] (L1=1,3-Bis(2-hydroxy-3,5-chlorosalicylideneamino) propan-2-ol) 1 and of [Cu2(L2)(3,5 prz)] (L2=1,3-Bis(2-hydroxy-bromosalicylideneamino) propan-2-ol) 2 are reported. The compounds were studied by elemental analysis, infrared and electronic spectra. The structure of the Cu2(L1)(3,5 prz)] complex was determined by x-ray diffraction. The magnetochemical characteristics of these compounds were determined by temperaturedependent magnetic susceptibility measurements, revealing their antiferromagnetic coupling. The superexchange coupling constants are 210 cm−1 for 1 and 440 cm−1 for 2. The difference in the magnitude of the coupling constants was explained by the metal-ligand orbital overlaps and confirmed by ab-initio restricted Hartree-Fock (RHF) calculations. In order to determine the nature of the frontier orbitals, Extended Hückel Molecular Orbital (EHMO) calculations are also reported.

scholarly journals Characterization of tin dioxide nanoparticles synthesized by oxidation

Cerâmica ◽  
2015 ◽  
Vol 61 (359) ◽  
pp. 328-333 ◽  
Author(s):  
R. C. Abruzzi ◽  
B. A. Dedavid ◽  
M. J. R. Pires
Keyword(s):  
Gas Sensors ◽  
Tin Dioxide ◽  
X Ray Diffraction ◽  
X Ray ◽  
Synthesis Conditions ◽  
Tetragonal Crystal ◽  
Tetragonal Crystal Structure ◽  
Activation Efficiency ◽  
Complementary Techniques

AbstractTin dioxide (SnO2) is a promising material with great potential for applications such as gas sensors and catalysts. Nanostructures of this oxide exhibit greater activation efficiency given their larger effective surface. The present study presents results of the synthesis and characterization of tin dioxide under different conditions via oxidation of solid tin with nitric oxide. SnO2powder was characterized primarily by X-ray diffraction and scanning electron microscopy, as well as complementary techniques such as energy-dispersive X-ray spectroscopy, dynamic light scattering and Fourier transform infrared spectroscopy. The results indicated that the established synthesis conditions were suitable for obtaining rutile tin dioxide nanoparticles with a tetragonal crystal structure.

Synthesis and Characterization of ZnS: Fe/ZnS Core-Shell Nanocrystals

2011 ◽  
Vol 148-149 ◽  
pp. 900-903
Author(s):  
Li Hua Li ◽  
Yong Jun Gu ◽  
Rui Shi Xie ◽  
Jian Guo Zhu
Keyword(s):  
Chemical Precipitation ◽  
Precipitation Method ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Pl Spectra ◽  
Zinc Blende ◽  
Diffraction Peaks ◽  
Zns Nanocrystals ◽  
Zinc Blende Structure

ZnS:Fe and ZnS:Fe/ZnS core-shell nanocrystals were synthesized by chemical precipitation method. It was found that the ZnS: Fe based nanocrystals possess zinc blende structure. Compared to ZnS: Fe nanocrystals, the intensity of the X-ray diffraction peaks of ZnS: Fe/ZnS nanocrystals reduced and these peaks moved to lower angles. TEM images show that ZnS: Fe based nanocrystals are spheroidal and the average particles size is about 3~4 nm. PL spectra of ZnS: Fe nanocrystals revealed several mission bands, ~406nm, ~444nm, ~416nm, However, PL spectra of ZnS: Fe/ZnS nanocrystals showed several mission bands, ~420nm, ~432nm, ~449nm.

Thermoelectric Characterization of Ti and In Double-Doped Cobalt Antimony Thin Films

2016 ◽  
Vol 847 ◽  
pp. 143-147
Author(s):  
Ya Dan Li ◽  
Zhuang Hao Zheng ◽  
Ping Fan ◽  
Jing Ting Luo ◽  
Guang Xing Liang ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermoelectric Properties ◽  
Flexible Substrate ◽  
Rf Magnetron Sputtering ◽  
X Ray Diffraction ◽  
Alloy Target ◽  
Diffraction Peaks ◽  
Thermoelectric Thin Films ◽  
Antimony Alloy

CoSb3 thermoelectric thin films were prepared on polyimide flexible substrate by radio frequency (RF) magnetron sputtering technology using a cobalt antimony alloy target. Ti and In were added into CoSb3 thin films by co-sputtering. The influence of Ti and In on the thermoelectric properties of CoSb3 thin films was investigated. X-ray diffraction result shows that the major diffraction peaks of all the thin films match the standard peaks related to the CoSb3 phase. The sample has best thermoelectric properties when the Ti sputtering time was 1min and In sputtering time was 30 seconds.

Ternary lead-chalcogenide room-temperature mid-wave infrared detectors grown by spray-deposition

MRS Advances ◽  
2018 ◽  
Vol 3 (5) ◽  
pp. 291-297 ◽  
Author(s):  
Hussain Abouelkhair ◽  
Pedro N. Figueiredo ◽  
Seth R. Calhoun ◽  
Chris J. Fredricksen ◽  
Isaiah O. Oladeji ◽  
...  
Keyword(s):  
Room Temperature ◽  
Heterogeneous Reaction ◽  
Spray Deposition ◽  
Complexing Agents ◽  
X Ray Diffraction ◽  
Lead Chalcogenide ◽  
Lead Chalcogenides ◽  
Diffraction Peaks ◽  
P Type

ABSTRACTTernary lead chalcogenides, such as PbSxSe1-x, offer the possibility of room-temperature infrared detection with engineered cut-off wavelengths within the important 3-5 micron mid-wave infrared (MWIR) wavelength range. We present growth and characterization of aqueous spray-deposited thin films of PbSSe. Complexing agents in the aqueous medium suppress unwanted homogeneous reactions so that growth occurs only by the heterogeneous reaction on the hydrophilic substrate. The strongly-adherent films are smooth with a mirror-like finish. The films comprise densely packed grains with tens of nm dimensions and a total film thickness of ∼400-500 nm. Measured optical constants reveal absorption out to at least 4.5 μm wavelength and a ∼0.3 eV bandgap intermediate between those of PbS and PbSe. The semiconducting films are p-type with resistivity ∼1 and 85 Ohm-cm at 300 and 80 K, respectively. Sharp x-ray diffraction peaks identify the films as Clausthalite-Galena solid-state solution with a lattice constant that indicates an even mixture of PbS and PbSe. The photoconductive response is observed at both nitrogen and room temperature up to at least 2 kHz chopping frequency.

Thermodynamic Analysis and Growth Characterization of thick GaN films grown by Chloride VPE using GaCl3/N2 and NH3/N2

1996 ◽  
Vol 423 ◽  
Author(s):  
Heon Lee ◽  
Masaaki Yuri ◽  
Tetsuzo Ueda ◽  
James S. Harris
Keyword(s):  
Gas Phase ◽  
Gas Flow ◽  
Chloride Transport ◽  
Growth Conditions ◽  
Band Edge Emission ◽  
X Ray Diffraction ◽  
High Crystalline Quality ◽  
Growth Characterization ◽  
Diffraction Peaks

AbstractThermodynamic calculations were carried out on chloride transport vapor phase epitaxy of GaN using GaCl3/N2 and NH3/N2. At typical growth temperature and gas flow rates, both GaN formation and gas phase etching reactions of GaN are thermodynamically favored. Under thermodynamic equilibrium, most ammonia should decompose to nitrogen and hydrogen gases and gas phase etching of GaN occurs by HCI. From experimental measurements, less than 10% of the incoming ammonia decomposes and under this condition, GaN formation from GaCl3 /N2, and NH3 /N2 is thermodynamically favored. Higher V/III ratios give a larger driving force for GaN fromation. These calculations match our experimental results. Experimentally, we have optimized the growth conditions of GaN. High crystalline quality thick GaN films (10 ˜15μm) were grown on c-Al2O3. The GaN films show band edge emission dominated PL at both room temperature and 77 K. Only one set of diffraction peaks from (1012) planes with 60° spacing in the φ-scan of X-ray diffraction are observed. This indicates that the GaN films grown on c-Al2O3 are single crystalline. Typical growth rates were about 10 ˜ I5μm/hr and typical Hall mobility values of GaN films were in the range of 3 to 40 cm2/Vsec.

Thermoelectric Characterization of Direct Current Magnetron Co-Sputtering Zinc Antimonide Thin Films

2013 ◽  
Vol 734-737 ◽  
pp. 2559-2562
Author(s):  
Ying Zhen Li ◽  
Ping Fan ◽  
Zhuang Hao Zheng ◽  
Peng Juan Liu ◽  
Qing Yun Lin ◽  
...  
Keyword(s):  
Thin Films ◽  
Direct Current ◽  
Annealing Temperature ◽  
X Ray Diffraction ◽  
Glass Substrates ◽  
Zinc Antimonide ◽  
Β Phase ◽  
Bk7 Glass ◽  
Diffraction Peaks

Direct current magnetron co-sputtering was used to deposit zinc antimonide thin films on BK7 glass substrates at room-temperature. Then the films were annealed at 573 K to 673 K for 1 hour in Ar atmosphere. The results indicate that the Seebeck coefficient of the thin films increase from 30.5 μVK-1to 132.5 μVK-1 when the annealing temperature changed. The electrical conductivity of the thin films increases from 3.45×103 to 6.86×103 Sm-1 and the Power Factor is enhanced greatly from 0.03×10-4 to 0.99×10-4 Wm-1K-2 when the annealing temperature reached 598 K. X-ray diffraction result shows that the major diffraction peaks of the thin films match those of β phase Zn4Sb3 and high crystalline thin films are achieved after annealing.

Novel Synthesis Process and Characterization of Li-Mn-O Spinels for Rechargeable Lithium Batteries

1997 ◽  
Vol 496 ◽  
Author(s):  
Toshimi Takada ◽  
Hirotoshi Enoki ◽  
Etsuo Akiba ◽  
Takenori Ishizu ◽  
Tatsuo Horiba
Keyword(s):  
Strong Dependence ◽  
Lattice Parameter ◽  
Synthesis Process ◽  
X Ray Diffraction ◽  
Rechargeable Lithium Batteries ◽  
Rietveld Refinements ◽  
Synthesis Conditions ◽  
New Process ◽  
Homogeneous Composition

ABSTRACTA new process has been developed for the synthesis of well-crystallized Li-Mn-O spinels with a homogeneous composition Li[LixMn2-x]O4 (0.0≤x≤0.333) using the stoichiometry mixtures of lithium acetate and manganese nitrate as starting materials. The crystal structure of these compounds was studied with Rietveld refinements of the X-ray diffraction profiles. The lattice parameter of the spinels shows a strong dependence on the composition and manganese oxidation state. SEM micrographs indicate that the crystallites appear as single crystals. The size of the crystallites are in the range of 0.1 – 2μm, depending on the synthesis conditions. Samples with x≤0.125 show good electrode performance for the cell Li/Li1+xMn2-xO4 in the 4V region, whereas Li4Mn5O2 (x=0.333) spinels show good cyclability with a rechargeable capacity of over 100mAh/g in the 3V region.

Preparation and Characterization of Catalysts Fe/SBA-15 for Fischer Tropsch Synthesis

2014 ◽  
Vol 805 ◽  
pp. 678-683
Author(s):  
Ângela da Costa Nogueira ◽  
Jocielys Jovelino Rodrigues ◽  
Liliane Andrade Lima ◽  
Meiry Glaúcia Freire Rodrigues
Keyword(s):  
Nitrogen Adsorption ◽  
Tropsch Synthesis ◽  
X Ray Diffraction ◽  
Fischer Tropsch ◽  
Fischer Tropsch Synthesis ◽  
X Ray ◽  
Acidic Conditions ◽  
Diffraction Peaks ◽  
Adsorption Desorption

In this study catalysts Fe/SBA-15 were prepared for Fischer-Tropsch Synthesis. SBA-15 samples were synthesized under acidic conditions using triblock copolymer Pluronic as a template and tetraethyl orthosilicate as a silica source.The molar composition was: 1.0 TEOS: 0017 P123: 8.14 HCl: 168 H2O. Fe/SBA-15 catalysts with different iron loading (15 wt. % and 20 wt. %) were prepared by wetness impregnation of relative SBA-15 with the desired amount of aqueous iron nitrate. The obtained catalyst were characterized by X ray diffraction (XDR), nitrogen adsorption-desorption and energy dispersive X-ray spectrometry (EDX). After impregnation of Fe the XRD profiles were almost unchanged and exhibited the high diffraction peaks of SBA-15 at low angles. The analysis of nitrogen adsorption-desorption was observed that the values of specific surface area decreased as the concentration of metal impregnated increased. And by the EDX analysis verified that the iron contents obtained are close to nominal levels of iron.

Effect of expandable and expanded graphites on the thermo-mechanical properties of polyamide 11

2018 ◽  
Vol 51 (2) ◽  
pp. 175-190 ◽  
Author(s):  
F Oulmou ◽  
A Benhamida ◽  
A Dorigato ◽  
A Sola ◽  
M Messori ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Xrd Analysis ◽  
Crystal Form ◽  
X Ray Diffraction ◽  
Polyamide 11 ◽  
X Ray ◽  
Diffraction Peaks ◽  
Graphite Composites ◽  
And Storage

The preparation and thermo-mechanical characterization of composites based on polyamide 11 (PA11) filled with various amounts of both expandable and expanded graphites are presented. Investigation conducted using X-ray diffraction (XRD), scanning electron microscopy and surface area analyses indicated how graphite expanded under the selected processing conditions. The XRD analysis on PA11/graphite composites revealed no change in the crystal form of the PA11, while the presence of diffraction peaks associated to the graphite-stacked lamellae can be still detected. All the investigated composites showed an improvement of the thermal stability and mechanical properties (elastic and storage moduli).

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