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  1. 12 Materials Science Poland
  2. 3 Bulletin of the Polish Academy of Sciences. Technical Sciences
  3. 2 Archives of Metallurgy and Materials
  4. 2 Ceramic Materials
  5. 2 Materiały Ceramiczne
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  1. 3 Garus Sebastian
  2. 3 Sochacki Wojciech
  3. 2 Kubanek Mariusz
  4. 2 Kwolek P.
  5. 2 Nabiałek Marcin
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  1. 2 2023
  2. 2 2022
  3. 2 2021
  4. 1 2020
  5. 4 2019
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1
Content available Influence of spatial distribution and the type of material on the occurrence of bandgaps in phononic crystals
Garus Sebastian, Sochacki Wojciech, Kwiatoń Paweł, Nabiałek Marcin, Petrů Jana, Kubanek Mariusz
Bulletin of the Polish Academy of Sciences. Technical Sciences
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2023
|
Vol. 71, nr 3
art. no. e144609
EN
The study investigated the effect of the fill factor, lattice constant, and the shape and type of meta-atom material on the reduction of mechanical wave transmission in quasi-two-dimensional phononic structures. A finite difference algorithm in the time domain was used for the analysis, and the obtained time series were converted into the frequency domain using the discrete Fourier transform. The use of materials with large differences in acoustic impedance allowed to determine the influence of the meta-atom material on the propagation of the mechanical wave.
2
Content available Propagation characteristics of longitudinal-torsion coupled waves in phononic crystal rods of chiral materials
Dai P., Wang R.
Archives of Mechanics
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2023
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Vol. 75, nr 5
543--558
EN
The chiral properties of chiral materials have a great influence on the wave propagation. Applying chiral materials to the design of phononic crystal rods not only increases the design space, but also may have other potential advantages. There is a lack of research on designing phononic crystal rods using chiral materials and the propagation characteristics of elastic waves in phononic crystal rods made of chiral materials. In this study, chiral materials are introduced into the design of phonon crystal rods for the first time, Bragg scattering type and local resonance type phononic crystal rods are designed using chiral materials. Dispersion equations for the propagation of longitudinal-torsion coupled waves in the phononic crystal rods are derived, and the effect of the chirality of the materials on their bandgap range is studied. The study shows that: in Bragg scattering type phonon crystal rods, material chirality can greatly affect the bandgap, among them, the chiral direction has the greatest effect, and in order to obtain a low-frequency wide bandgap, the chiral coefficients of the materials should be increased as much as possible with the chiral directions of the two cells being opposite; in the local resonance type phonon crystal rod, only two types of oscillators are added to the material simultaneously to produce a band gap, and the starting frequency obtained is much lower than that of the Bragg scattering type.
3
Content available Biosynthetic of Titanium Dioxide Nanoparticles Using Zizyphus Spina-Christi Leaves Extract: Properties
Alobaidi Tuqa B., Alwared Abeer I.
Journal of Ecological Engineering
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2022
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Vol. 23, nr 1
315--324
EN
The present project utilizes a straightforward, inexpensive, and environmentally friendly approach to produce Titanium dioxide nanoparticles utilizing Zizyphus Spina-Christi leaves (Z-TiO2). Ultra-Spectrophotometry (UV-Vis) was used to characterize the synthesized nanoparticles, which showed the production of nanoparticles at 320 nm absorbance. To investigate functional groups, Fourier Transform Infrared Spectroscopy (FTIR) has been used. The presence of Titanium Dioxide was verified using Energy Distribution X-ray Spectroscopy (EDS). Surface area is calculated using the Brunauer Emmett Teller (BET) formula. Images from Field Emission Electron Microscopy (FE-SEM) verified the nanoparticles' spherical shape and relatively homogenous size distribution. These findings demonstrated that the production of Z-TiO2 nanoparticles was successful.
4
Content available Minimizing the number of layers of the quasi one-dimensional phononic structures
Garus Sebastian, Sochacki Wojciech, Kubanek Mariusz, Nabiałek Marcin
Bulletin of the Polish Academy of Sciences. Technical Sciences
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2022
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Vol. 70, nr 1
art. no. e139394
EN
In the work, multi-criteria optimization of phononic structures was performed to minimize the transmission in the frequency range of acoustic waves, eliminate high transmission peaks with a small half-width inside of the band gap, and what was the most important part of the work – to minimize the number of layers in the structure. Two types of the genetic algorithm were compared in the study. The first one was characterized by a constant number of layers (GACL) of the phononic structure of each individual in each population. Then, the algorithm was run for a different number of layers, as a result of which the structures with the best value of the objective function were determined. In the second version of the algorithm, individuals in populations had a variable number of layers (GAVL) which required a different type of target function and crossover procedure. The transmission for quasi-one-dimensional phononic structures was determined with the use of the transfer matrix method algorithm. Based on the research, it can be concluded that the developed GAVL algorithm with an appropriately selected objective function achieved optimal solutions in a much smaller number of iterations than the GACL algorithm, and the value of the k parameter below 1 leads to faster achievement of the optimal structure.
5
Content available Optimization of a Bandgap in the Ultrasonic Phononic Coating
Garus Sebastian, Sochacki Wojciech, Garus Justyna, Sandu Andrei Victor
Archives of Metallurgy and Materials
|
2021
|
Vol. 66, iss. 2
537--542
EN
This work concerns the study of the coatings for the ultrasound frequency range as a quasi one-dimensional phononic crystal structure protecting a sea object against high resolution active sonar in the frequency range most commonly found for this type of equipment. The topology of the examined structure was optimized to obtain a band gap in the 2.2-2.3 MHz frequency band. For this purpose, a genetic algorithm was used, which allows for optimal distribution of individual elements of the ultrasound multilayer composite. By optimal distribution is meant to achieve a structure that will allow minimal reflectance in a given frequency range without height reflectance peaks with a small half width. Analysis of the wave propagation was made using the Transfer Matrix Method (TMM). As part of the research, 15 and 20-layer structures with reflectance at the level of 0.23% and 0.18%, respectively, were obtained. increasing the number of layers in the analyzed structures resulted in finding such a distribution in which a narrow band of low reflectance was obtained, such distributions could also be used as bandpass filters. The use of a genetic algorithm for designing allows to obtain modern coatings, the characteristics of which result from the structure.
6
Content available remote Ultrawide bandgap by 3D monolithic mechanical metastructure for vibration and noise control
Muhammad, Lim C. W.
Archives of Civil and Mechanical Engineering
|
2021
|
Vol. 21, no. 2
197--207
EN
The all-direction vibration and noise control by metastructures have received high demands in the vibroacoustic community in the recent past to solve multiple vibration and noise-related engineering problems. This class of elastic metamaterial has grasped a strong root in this community due to its versatile wave manipulation characteristics, including frequency bandgap property. Inspired by the idea of metamaterial and computational mechanics in breakthrough research for vibration and noise control technology, the present study proposes a novel 3D phononic metastructure that is capable of generating low-frequency extremely wide three-dimensional complete bandgap with relative bandwidth Δω/ωc=171.5%. The study is based on analytical modeling, numerical finite element analysis and experiment on 3D printed prototype. The proposed monolithic metastructure is comprised of elastic beams connected orthogonally with rigid spherical masses. The axial compression mode of a complete unit cell structure and the flexural stiffness of beams are manipulated to generate low-frequency extremely wide bandgap. By the principle of modal masses participation/mode separation, the opening and closing of the bandgap is analyzed. The results are corroborated by two different numerical FE solutions on the frequency response spectrum, and the models are validated by performing a vibration test on 3D printed prototype. The wave attenuation over ultrawide frequency range is demonstrated through numerical and experimental approaches, and excellent agreement is reported. The proposed monolithic metastructure design may find potential applications in industrial and infrastructural devices where noise and vibration control over ultrawide frequency range are desirable in all directions.
7
Content available remote Synthesis, photophysical properties and electrochemical polymerization of a new blue fluorescent compound based on 3,4-ethylenedioxythiophene moiety
Guergouri Mounia, Bensegueni Rafik, Bencharif Leïla
Materials Science Poland
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2020
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Vol. 38, No. 1
151--158
EN
New monomer, 4,4’-[(2,3-dihydrothieno[3,4-b][1,4]diorin-5-yl)vinyl]-1,1’-biphenyl (BPE), was synthesized, characterized and polymerized electrochemically via a potentiostatic method. The corresponding polymer poly(4,4’-[(2,3-dihydrothieno[3,4-b][1,4] diorin-5-yl)vinyl]-1,1’-biphenyl) (PBPE) obtained as a thin-layer film, was characterized by cyclic voltammetry, X-ray photoelectron spectroscopy, infrared spectroscopy and UV-Vis spectroscopy. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of the obtained polymer were determined from cyclic voltammograms as –4.89 eV and –3.81 eV, respectively. Its optical and electrochemical band gaps were calculated, and found to be 1.08 eV and 1.49 eV, respectively. PBPE can be used as a donor material in bilayer organic photovoltaic solar cells having PCBM as acceptor material.
8
Content available Fluid-fluid phononic crystal with elastic coat working in audible frequencies
Klimek Aleksandra
Vibrations in Physical Systems
|
2019
|
Vol. 30, nr 1
art. no. 2019145
EN
Phononic Crystals are receiving rising attention in the field of modern acoustic materials. PCs are artificial structures of periodically arranged scatterers. Such a structure enables creating a band gap in which, due to the Bragg diffraction phenomenon, vibrations are restrained or even forbidden. In this paperwork, the fluid-fluid PC is tested and simulated - the scatterers are constructed of water cylinders with an ethylene propylene diene monomer coat (EPDM - a hyperelastic rubber) and are embedded in air. The band gap is calculated to emerge in the audible range of frequency. Every simulation is performed with the use of the finite element method.
9
Content available remote Właściwości strukturalne, optyczne i elektryczne TiO2 modyfikowanego Fe2O3
Karoń Iwona, Radecka Marta
Materiały Ceramiczne
|
2019
|
T. 71, nr 1
17--24
PL
Celem pracy było określenie własności strukturalnych, elektrycznych i optycznych TiO2 modyfikowanego Fe2O3. Materiały TiO2-Fe2O3 syntezowano metodą zol-żel w zakresie (0-2)% mol. Fe2O3. Badania dyfrakcji promieniowania rentgenowskiego XRD wskazują, że niedomieszkowany TiO2 oraz materiały o zawartości do 0,25% mol. Fe2O3 krystalizują w strukturze rutylu. Przewodnictwo elektryczne mierzono w funkcji składu oraz temperatury (425-700 °C). Położenie i kształt krawędzi absorpcji podstawowej zależy od koncentracji domieszki. Własności strukturalne i elektryczne materiałów potwierdzają zakres tworzenia roztworów stałych.
EN
The aim of this work was to determine the structural, electrical and optical properties of the TiO2 modified with Fe2O3. Fe2O3-TiO2 materials were synthetized by the sol-gel method in the range 0-2 mol% Fe2O3. XRD X-ray diffraction studies indicate that undoped TiO2 and materials with a content of up to 0.25 mol% Fe2O3 crystallize in the rutile structure. Electrical conductivity was measured as a function of composition and temperature (425-700 °C). The location and shape of the primary absorption edge depends on the concentration of the admixture. Structural and electrical properties of materials confirm the range of solid solution formation.
10
Content available remote Preparation and properties of Ba2+–Y3+ co-doped γ-Ce2S3 red pigment
Li Xin, Li Yueming, Li Zhike, Wang Zhumei, Hong Yan, Song Fusheng
Materiały Ceramiczne
|
2019
|
T. 71, nr 4
378--388
EN
In this study, Ba2+-Y3+ co-doped γ-Ce2S3 (abbreviated as γ-[Ba,Y]-Ce2S3) red pigments were synthesized by a co-precipitation method according to the composition of n(Ba)/n(Ce1-xYx) = 0.1 (molar ratio, x = 0, 0.01, 0.03, 0.05, and 0.10 mol). The corresponding vulcanized products, γ-[Ba,Y]-Ce2S3 red pigment (SYx), were prepared at 850 °C for 150 min by using CS2 as a sulphur source. The effect of the Y3+ doping content on the phase composition, chromaticity, and thermal stability of Ba2+-Y3+ co-doped γ-Ce2S3 was systematically investigated by FE-SEM, EDS, XRD, Raman spectroscopy, HR-TEM, XPS, CIELAB colorimeter, and TG-DTA. The results show that a pure γ phase can be obtained for SYx at 850 °C, when x is varied from 0 to 0.05 mol. Whereas new heterogeneous phases, i.e., α-Ce2S3 and BaY2S4, were observed when the Y3+ content was larger than 0.05. As the Y3+ content increased, the band gap of γ-[Ba,Y]-Ce2S3 increased from 2.12 eV to 2.15 eV, which led to a colour change from red to red-orange. The chromaticity value of the pigments was raised from L* = 31.84, a* = 30.95, b* = 23.63 (S.Y0.00) to L* = 36.69, a* = 41.83, b* = 41.00 (S.Y0.01), indicating that the Ba2+-Y3+ co-doping can effectively increase the chromaticity value. The S.Y0.01 sample still presented a pure γ-phase after heat treatment at 440 °C for 10 min in air, which indicated that the Ba2+-Y3+ co-doping successfully increased the thermal stability of the γ-[Ba,Y]-Ce2S3 red pigment.
PL
W niniejszych badaniach, czerwone pigmenty Ba2+-Y3+ γ-Ce2S3 (w skrócie γ-[Ba,Y]-Ce2S3) zostały zsyntetyzowane metodą współstracania zgodnie ze składem n(Ba)/n(Ce1-xYx) = 0,1 (stosunek molowy, x = 0, 0,01, 0,03, 0,05 i 0,10 mol). Odpowiednie produkty wulkanizowane, czerwony pigment γ-[Ba,Y]-Ce2S3 (SYx), wytworzono w 850 °C przez 150 min, stosując CS2 jako źródło siarki. Wpływ zawartości domieszki Y3+ na skład fazowy, chromatyczność i stabilność termiczną γ-Ce2S3 współdomieszkowanego Ba2+-Y3+ był systematycznie badany za pomocą FE-SEM, EDS, XRD, spektroskopii Ramana, kolorymetru HR-TEM, XPS, CIELAB i TG-DTA. Wyniki pokazują, że dla SYx można uzyskać w 850 °C czystą fazę γ, gdy x zmienia się od 0 do 0,05 mola. Podczas gdy nowe heterogeniczne fazy, tj. α-Ce2S3 i BaY2S4, zaobserwowano, gdy zawartość Y3+ była większa niż 0,05. Wraz ze wzrostem zawartości Y3+ pasmo wzbronione γ-[Ba, Y]-Ce2S3 wzrosło z 2,12 eVdo 2,15 eV, co doprowadziło do zmiany koloru z czerwonego na czerwono-pomarańczowy. Wartość chromatyczności pigmentów podniesiono z L* = 31,84, a* = 30,95, b* = 23,63 (S.Y0,00) do L* = 36,69, a* = 41,83, b* = 41,00 (S.Y0.01), wskazując, że współdomieszkowanie Ba2+-Y3+ może skutecznie zwiększyć wartość chromatyczności. Próbka S.Y0.01 nadal wykazywała czystą fazę γ po obróbce cieplnej w 440 °C przez 10 min w powietrzu, co wskazywało, że jednoczesne domieszkowanie Ba2+-Y3+ skutecznie zwiększyło stabilność termiczną czerwonego pigmentu γ-[Ba,Y ]-Ce2S3.
11
Content available Manufacturing process and characterization of electrospun PVP/ZnO NPs nanofibers
Matysiak W., Tański T., Zaborowska M.
Bulletin of the Polish Academy of Sciences. Technical Sciences
|
2019
|
Vol. 67, nr 2
193--200
EN
Constantly developing nanotechnology provides the possibility of manufacturing nanostructured composites with a polymer matrix doped with ceramic nanoparticles, including ZnO. A specific feature of polymers, i.e. ceramic composite materials, is an amelioration in physical properties for polymer matrix and reinforcement. The aim of the paper was to produce thin fibrous composite mats, reinforced with ZnO nanoparticles and a polyvinylpyrrolidone (PVP) matrix obtained by means of the electrospinning process and then examining the influence of the strength of the reinforcement on the morphology and optical properties of the composite nanofibers. The morphology and structure of the fibrous mats was examined by a scanning electron microscope (SEM) with an energy dispersive spectrometer (EDS) and Fourier-transform infrared spectroscopy (FTIR). UV –Vis spectroscopy allowed to examine the impact of zinc oxide on the optical properties of PVP/ZnO nanofibers and to investigate the width of the energy gap.
12
Content available Defect modes properties in one-dimensional photonic crystals employing a superconducting nanocomposite material
Aly A. H., Elsayed H. A., Malek C.
Optica Applicata
|
2018
|
Vol. 48, nr 1
53--64
EN
In the present work, we investigate theoretically the transmission characteristics of one-dimensional photonic crystals that contain a defect layer of a nanocomposite material in infrared radiation. The theoretical treatment is obtained depending on the fundamentals of the characteristic matrix method. Here, the nanocomposite designed from nanoparticles of a superconducting material is arranged into a dielectric medium. The numerical results clarify the acute effect of the volume fraction and the operating temperature on the effective permittivity of the nanocomposite material. Therefore, the volume fraction, the operating temperature and other parameters such as the permittivity of the dielectric material and the threshold frequency could have a significant effect on the characteristics of the defect modes. Thus, our structure may be very promising in many applications such as narrow band filters and among optoelectronic applications.
13
Content available remote Fabrication and characterization of Zn doped CuO nanofiber using newly designed nanofiber generator for the photodegradation of methylene blue from textile effluent
Sethuraman R. G., Venkatachalam T., Kirupha S. D.
Materials Science Poland
|
2018
|
Vol. 36, No. 3
520--529
EN
High aspect ratio, Zn doped copper oxide (Zn-CuO) nanofibers have been fabricated employing a newly designed electrospun coating unit using copper acetate, sodium hydroxide and polyethylene glycol in aqueous state. The prepared Zn doped copper oxide (Zn-CuO) nanofibers were sintered at 400 °C, 500 °C and 600 °C separately and characterized using X-ray diffraction XRD, Fourier transformation infrared spectroscopy FT-IR, scanning electron microscopy SEM, energy dispersive spectroscopy EDS. The average crystallite size was in the range of 28 nm to 30 nm. Optical properties of Zn-CuO nanofibers were analyzed using UV-DRS studies which showed a blue shift in the absorption band. An increase in band gap with the increase in postannealing temperature was observed due to the blue shift in absorption edge of CuO causing enhanced photodegradation. The catalytic properties of the CuO nanofibers were tested using methylene blue in aqueous medium. The influences of parameters responsible for high photodegradation were optimized and the rate of the photodegradation process was calculated using photodegradation kinetics. The reusability test was conducted to find the stability of the fabricated Zn-CuO nanofibers.
14
Content available remote Effects of aluminum (Al) incorporation on structural, optical and thermal properties of ZnO nanoparticles
Ahammed N., Hassan M. S., Hassan M.
Materials Science Poland
|
2018
|
Vol. 36, No. 3
419--426
EN
In this research article, pure and 1 %, 3 % and 5 % aluminium doped zinc oxide nanoparticles (NPs) were prepared via sol-gel method and then calcined at 500 °C. X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared (FT-IR) spectroscopy, UV-Vis spectroscopy, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) techniques were used to investigate the structural, optical and thermal properties of synthesized pure and Al doped ZnO nanoparticles. Energy dispersive X-ray spectroscopy (EDX) analysis revealed high purity of nanoparticles in the synthesized products without any impurity peaks. Mean dimension of the nanoparticles was ~28 nm and they were hexagonal in shape, according to the images analyzed by transmission electron microscope (TEM). The optical absorption spectra of pure and Al doped ZnO samples studied using UV-Vis spectrometry have been presented and we have observed that the band gap increases with increasing Al concentration. In FT-IR spectra, the broad absorption peaks around 485 cm-1 and 670 cm cm-1 were assigned to Zn–O vibration. Above 450 °C, the TG curve became flat what means there was no weight loss. In the DSC curve it is seen that the transition at 150 °C was highly exothermic because of structural relaxation and on doping the exothermic peaks became shifted to the lower value of temperature. These types of materials are very useful in optoelectronics applications.
15
Content available remote Analysis of glass forming ability using percolation concept and tunability of physical parameters of a-Ge12Se76 – xAs12Bix glassy semiconductors
Sharma I., Sunder S.
Materials Science Poland
|
2018
|
Vol. 36, No. 2
242--254
EN
Glass forming ability of lone-pair semiconductors was analyzed for (x = 0, 2, 4, 6, 8, 10) system. Values of lone pair electrons L were calculated using average coordination number of valence electrons. These values were found to decrease, as the system was moving towards the rigid region. L > 3 values showed vitreous state. Deviation of the stoichiometry confirmed the chalcogen-rich region. A linear correlation was found between the mean bond energy and glass transition temperature. Chemical Bond Approach model was applied to calculate the cohesive energy of the system. A linear relationship was found to exist between the cohesive energy and the theoretical band gap, calculated using Shimakawa relation. A decrease in both parameters was explained on the basis of average stabilization energy and electronegativity of the system. The density values were found to increase and may account for higher refractive index of the system. Large Bohr radius of the Bi atom accounted for an increase in the polarizability. Other parameters viz. degree of covalency, packing density, compactness, molar volume, free volume percentage, excess volume and polaron radius were also calculated. An effort was made to correlate the effect of Bi addition to Ge12Se76 – xAs12Bix lone-pair semiconductor on the basis of the structure of the glassy matrix or the connectedness of the material.
16
Content available High-performance quasi one-dimensional mirrors of mechanical waves built of periodic and aperiodic structures
Garus S., Sochacki W.
Journal of Applied Mathematics and Computational Mechanics
|
2018
|
Vol. 17, nr 4
19--24
EN
The work studied the reflectance for quasi one-dimensional phononical structures. In composite superlattices, the thickness of the layers, their arrangement and selection of constituent materials with appropriate properties such as the density and velocity of mechanical waves propagation allows for the creation of a phononic band gap (PhBG) phenomenon. PhBG is characterized by high reflectance of the mechanical wave incident on the analyzed structure, which means that the wave does not propagate in the superlattice. The paper proposes periodic and aperiodic structures characterized by a wide range of reflectance for the ultrasonic frequencies of mechanical waves and shows how the change the thickness of the layer affects the properties of the analyzed structures.
17
Content available remote Structural, optical and electrical characterization of CBD synthesized CdO thin films: influence of deposition time
Das M.R., Mukherjee A., Mitra P.
Materials Science Poland
|
2017
|
Vol. 35, No. 3
470--478
EN
Cadmium oxide (CdO) thin films were grown on glass substrates by chemical bath deposition (CBD) method for different deposition times using cadmium acetate as cationic precursor. The structural and optical characterization was carried out using XRD, TEM, and UV-Vis spectrophotometer measurements. Structural analyses with XRD confirmed cubic structure of the CdO. Average particle size estimated from Rietveld refinement method of XRD pattern corresponded well with TEM measurement. The optical band gap varied between 2.35 eV to 2.48 eV with deposition time and an increase in optical band gap with decreasing film thickness was observed. The AC electrical conduction behavior of the CdO film was investigated as a function of temperature as well as frequency. The conductivity measurements indicated localized conduction and hopping of carriers between localized states. The value of real part of dielectric constant was found to decrease with frequency and increase with temperature. The Nyquist plots at different temperatures showed the existence of both grains and grain boundaries contributing to conduction mechanism.
18
Content available remote Structural, optical and dielectric studies of lithium sulphate monohydrate single crystals
Najar F. A., Vakil G. B., Want B.
Materials Science Poland
|
2017
|
Vol. 35, No. 1
18--31
EN
Optical, dielectric, and thermal properties of lithium sulphate monohydrate crystals grown by slow evaporation method have been studied. The crystal structure was resolved by direct methods using single crystal X-ray diffraction data collected at room temperature and refined by full-matrix least-squares procedures to a final R-value of 0.0174. Plasma energy, Penn gap, Fermi energy and electronic polarizability of the grown crystal were calculated from single crystal XRD data. The electronic polarizability of lithium sulfate monohydrate was also calculated and compared with the theoretical data using Clausius-Mossotti equation. Optical band gap calculated from optical data for the grown crystal is 4.49 eV. Fourier Transform Infrared Spectroscopy study confirmed the presence of water in the crystal structure. The AC conductivity, dielectric constant and dielectric loss of the grown crystal were systemically investigated, showing a peak at about 130 °C which could be attributed to the water molecules in the crystal structure. The anomalous dielectric properties shown by the crystal have been correlated with its thermal behavior. The title crystal obeys Jonscher’s power law relation; σ(ω) = σο+ Aωs, with temperature dependent exponent s < 1. The activation energy calculated for the material is 0.24 eV and suggests protonic conduction by hopping mechanism in addition to cationic conduction by lithium ions. The micro-indentation study was also carried out which revealed that the crystal belongs to a category of soft materials.
19
Content available remote Ultrasound mediated synthesis of CuS nanocrystallites
Panda B. B., Sharma B., Rana R. K.
Materials Science Poland
|
2016
|
Vol. 34, No. 2
446--450
EN
We present a unique ultrasonication based method for the preparation of copper sulphide nanoparticles in ambient air using a single precursor complex, which acts as a source of both metal and sulphur. The nanoparticles of 3.31 nm have been prepared successfully by the method and characterized using powder X-ray diffractogram (PXRD), dynamic light scattering (DLS) analysis UV-Vis spectroscopy and fluorescence spectroscopy. The results proved that copper sulphide nanoparticles of hexagonal structure (covellite phase) can be prepared by sonochemical method within a very short reaction time of ~5 min. The band gap of the nanomaterial has also been calculated from absorption spectrum and was found to be 2.36 eV.
20
Content available remote Structural and optoelectronic properties of glucose capped Al and Cu doped ZnO nanostructures
Patwari G., Kalita P. K., Singha R.
Materials Science Poland
|
2016
|
Vol. 34, No. 1
69--78
EN
Al and Cu doped ZnO nanoparticles are considered as appropriate for modulation of structural and optoelectronic properties. Al atoms are found to substitute the host Zn whereas Cu dopants mainly segregate in grain boundaries and thereby determine the optical properties. The undoped as well as Al and Cu doped ZnO exhibit spherical well defined particles. The spherical nanoparticles change to rod type structures on co-doping. The average particle size decreases on doping what consequently results in an increment in band gap. Blue shift in UV absorption is governed by the functional group of glucose; further blue shift occurring on metal doping may be attributed to Burstein-Moss effect. PL spectra of doped and undoped ZnO show a dominant near band gap UV emission along with visible emission owing to the defects. The PL peak intensity increases on doping with Cu and Al. The linear I-V characteristics indicate the ohmic behavior of ZnO nanostructures.
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