Crystallite Structure Research Articles

Effect of annealing temperature on the synthesis and photocatalytic properties of Bi0.65K0.2Ba0.15FeO3 perovskite-like nanoparticle synthesized by sol-gel method

BackgroundBiFeO3 shows promising applications in photocatalytic degradation, purification process, and in clean energy generation. The various fascinating properties of bismuth ferrite nanoparticles can be improved by doping the material at either of the A or B sites to give it extra photocatalytic advantage toward decreasing the energy bandgap and other photophysical properties of the material.ResultsIn this research, pure Bi0.65K0.2Ba0.15FeO3 perovskite material was synthesized using the sol-gel method via citric acid route in the presence of sodium dodecyl sulfate (SDS). The powdered nanoparticles were annealed at different annealing temperatures of 600, 700, and 800 °C each for 4 h in a muffle furnace and coded K2BFO 600, K2BFO 700, and K2BFO 800 corresponding to the annealing temperature of each portion. The powder nanoparticles were characterized using powdered X-ray diffraction (PXRD) to determine the crystallite structure. The samples displayed similar peak patterns with increase in intensity as the annealing temperature is increased indicating an increase in crystallinity. The impurity peaks in K2BFO 800, however, show that the sample may contain a secondary phase. Scanning electron microscopy (SEM) was used to determine the morphology, and UV-Vis spectroscopy indicated that all the powders were photoactive within the visible region of the electromagnetic spectrum. ATR-FTIR spectra of the samples were collected to study the formation and phase purity of the B-site in the perovskite structures. The photocatalytic performance of the powder was tested on methylene blue dye under visible light irradiation for the degradation studies. All powders showed photocatalytic ability after 2 h of irradiation with the powder annealed at 800 °C being better. The photocatalytic activities of the powders showed improvement on addition of 2 drops of 1 M H2O2 (80% degradation for K2BFO 800). The bandgap energy of K2BFO 800, 700, and 600 was estimated at approximately 2.00, 2.12, and 2.18 eV, respectively, using Tauc’s equation. The improved activity is as a result of photoabsorption of visible light by the doped powders causing generation of electrons and holes. The kinetic studies were carried out and the mechanisms of the photocatalytic reaction proposed.ConclusionThe effect of annealing temperature on synthesis of the material shows enhanced photoactivity in the presence of hydrogen peroxide leading to improved performance for the degradation of MB, and the catalyst can be said to be a good candidate for the treatment of waste materials.

Even Visually Intact Cell Walls in Waterlogged Archaeological Wood Are Chemically Deteriorated and Mechanically Fragile: A Case of a 170 Year-Old Shipwreck.

Structural and chemical deterioration and its impact on cell wall mechanics were investigated for visually intact cell walls (VICWs) in waterlogged archaeological wood (WAW). Cell wall mechanical properties were examined by nanoindentation without prior embedding. WAW showed more than 25% decrease of both hardness and elastic modulus. Changes of cell wall composition, cellulose crystallite structure and porosity were investigated by ATR-FTIR imaging, Raman imaging, wet chemistry, 13C-solid state NMR, pyrolysis-GC/MS, wide angle X-ray scattering, and N2 nitrogen adsorption. VICWs in WAW possessed a cleavage of carboxyl in side chains of xylan, a serious loss of polysaccharides, and a partial breakage of β-O-4 interlinks in lignin. This was accompanied by a higher amount of mesopores in cell walls. Even VICWs in WAW were severely deteriorated at the nanoscale with impact on mechanics, which has strong implications for the conservation of archaeological shipwrecks.

Morphological and Structural Properties of Sol-Gel Derived ZnO Thin Films Spin-Coated on Different Substrates

In this work, ZnO thin films were prepared by the low-cost sol-gel deposition method onto six different substrates (glass, ITO coated glass, sapphire (Al2O3), p-Si, p-GaN and polyethylene terephthalate (PET)) to study the effects of these substrates on the morphological and structural properties of the produced films. Precursor solution is Zinc acetate dihydrate based dissolved in ethanol with monoethanolamine (C2H7NO) added to act as a stabilizing agent to the sol. The corresponding ZnO thin films were characterized using field emission scanning electron microscopy (FESEM), high resolution X-ray diffraction (XRD) and atomic force microscopy (AFM). Results revealed distinct morphological and structural properties of ZnO thin films deposited on each substrate. The most uniform morphology was identified on glass, owing to the acquisition of the averagely stable grain sizes (58 nm – 61 nm) and thin film thicknesses (280 nm – 325 nm). High resolution XRD analysis showed that the films deposited on glass, ITO, p-Si, and p-GaN were attributed to hexagonal crystallite structures while the films deposited on sapphire and PET substrates exhibited amorphous phases. Amongst the samples, the ZnO thin film spin coated on p-Si demonstrated preferred orientation in (002) direction.

Regenerated Cellulose Fibers Wetspun from Different Waste Cellulose Types

ABSTRACT Regenerated cellulosic fibers were successfully spun from various waste cellulose sources (cotton linter, bagasse, and cardboard) suitable for use as a textile fibers using a wet spinning process with an ionic liquid/dimethyl sulfoxide (IL/DMSO) mixture as the solvent. The solubility of the waste cellulose sources in IL/DMSO varies according to the source of the raw material. Regenerated fibers can be spun from all the waste feedstock, the spinnability and fiber tensile strength is governed by the DP and chemical composition of the cellulose. The structural properties of the spun fibers are determined by x-ray diffraction, thermalgravimetric analysis, and scanning electron microscope. The results reveal that the properties of the starting materials and thus how the waste feed streams are pretreated have a significant impact on the mechanical properties, crystallite structure, thermal stability, and the morphology of the fibers.

Synthesis, morphological and electromagnetic evaluations of Ca doped Mn spinel nanoferrites for GHz regime applications

Calcium (Ca) doped manganese (Mn) spinel nanoferrites with the composition of Ca1−xMnxFe2O4 where x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0 are synthesized by sol-gel self-ignition route. XRD, FESEM and FTIR are employed to investigate the cubic crystallite structure, phase, morphology, grain size and vibrational bands respectively. Functional bands and phase of the Ca-doped Mn nanoferrites were evaluated using FTIR. The values of the force constants were increased with Ca substitution in Mn ferrites. The systematic effects of Ca on the microstructure and morphology were also examined using FESEM. The electromagnetic analysis including complex permittivity, permeability, conductivity and loss tangent of the Ca doped Mn nanoferrites in the frequency ranges of 1 GHz–6 GHz are studied using VNA with coaxial probe. Conductivity varies by increasing the Ca substitution in Mn spinel ferrites. This may be due to the electron and polaron hopping between Fe3+ and Fe2+ ions. The quality factor shows highest values after 2.3 GHz frequency region for all the Ca doped nanoferrites. The reasonable conduction mechanism into the higher frequency region may be suited for Mn–Ca nanoparticles as a commercially industrial material for microwave high frequency GHz regime applications.

Optical and electronic properties of chemical bath deposited p-CuO and n-ZnO nanowires on silicon substrates: p-CuO/n-ZnO nanowires solar cells with high open-circuit voltage and short-circuit current

P-type cupric oxide (p-CuO) and p-type cupric-oxide/n-type zinc oxide nanowires (p-CuO/n-ZnO NWs) heterojunction diodes were fabricated by employing chemical bath deposition technique on n-silicon (n-Si) substrate. The work demonstrates the potential of zinc oxide nanowires as window layer owing to its wide and direct band gap for metal oxide based solar cells. Optical and electronic properties of the CuO film and ZnO nanowires including refractive index, absorption coefficient and band gaps were investigated by using spectroscopic ellipsometric analysis. Impact of nanowire morphology, chemical composition and crystallite structures on optical and photovoltaic performance of p-CuO/n-Si and p-CuO/n-ZnO NWs were investigated. Absorption coefficient in the near UV–visible range was observed to improve significantly by incorporating n-ZnO nanowires which was desired for the solar cell applications. The comparative photovoltaic performance showed improvements of both the short-circuit current density (Jsc) and open circuit voltage (Voc), due to reduced interface recombination and enhanced absorption for the increased surface-to-volume ratio of ZnO nanowires in the p-CuO/n-ZnO NWs heterojunction. Photovoltaic performance with Jsc, Voc and power conversion efficiency of 11.1 mA/cm2, 1.1 V and 4.19% was obtained. Therefore, the work emphasizes importance of using the combination of n-ZnO nanowires and p-CuO film as the wide- and low- band gap materials for improving performance of the future low-cost solar cell with superior efficiency.

One-step synthesis of CuO nanoparticles and their effects on H9c2 cardiomyoblasts cells

Copper(II) oxide (CuO) nanoparticles (NPs) were synthesized by the calcination of a mixture of copper acetate and orange peel powder at 600 °C for 4 h. The average crystallite size and structure of the prepared sample was predicted by X-ray diffraction (XRD) analysis. Optical property of the sample was measured by using UV-visible absorption spectroscopy. Fourier transform infrared (FT-IR) spectroscopy was employed to find metal-oxygen bond and surface groups of the sample. Both scanning and transmission electron microscopic analyses reveal that the CuO particles adopt leaf and irregular plate-like morphologies. The average length of CuO nanoleaves is 54 nm. The effect of morphology by different types of orange peel powders was also investigated. Energy dispersive X-ray spectrum (EDX) shows the characteristic peaks of Cu, C and O only. Furthermore, the prepared CuO NPs with or without orange peel powders were applied on H9c2 cardiomyoblasts cells to find their cytotoxicity. Research Highlights Orange peel extract is used to produce Copper (II) oxide nanoparticles. Solvent free synthesis of CuO nanoparticles. Highly stable CuO nanoparticles are produced by this method. Synthesized CuO nanoparticles show leaves-like morphology.

The crystallization behavior of poly(l-lactide)/poly(d-lactide) blends: effect of stirring time during solution mixing

Blending of poly(l-lactide) and poly(d-lactide) (PLLA, PDLA) results in the formation of poly(lactide) stereocomplex crystallites (SC). For the preparation method, numerous reports employed solution mixing and stirring to receive a product with uniform performance. However, the effect of stirring time during solution mixing on the subsequent crystallization behavior did not clear yet, and which is important for solution crystallization, casting and spinning. In this paper, linear PLLA and PDLA with various molecular weights were synthesized. The PLLA and PDLA solutions were mixed together and stirred for different times before casting. Results revealed that the structures of PLA SC and homochiral crystallites (HC) did not vary with change in the stirring time. More amount of content of SC with uniform structure and less amount of content of HC were produced in the specimens stirred for longer time. When the specimens crystallized either from the melt or from the melt-quenching, less amount of content of crystallites (total crystallinity of SC and HC) was produced and the melting temperature of SC and HC depressed in the specimens that were stirred for longer time. With the increase in molecular weights, the effect of stirring time on the crystallization behaviors declined. This investigation provides a route to tailor the crystallization behavior of PLLA/PDLA specimens.

Structure and in vitro digestion of amylosucrase-modified waxy corn starch as affected by iterative retrogradation

ABSTRACT This study evaluated the effects of iterative retrogradation on the structure and in vitro digestion of amylosucrase-treated waxy corn starch. Iterative retrogradation was conducted by repeating the set of autoclaving and retrogradation (4°C for 5 d) up to three times. After amylosucrase treatment, the average branch chain length increased. With retrogradation cycle count, melting enthalpy and temperature of amylosucrase-treated starch increased from 3.2 to 9.2 J/g and from 89.5°C to 95.2°C, respectively, and its relative crystallinity increased from 33.1% to 40.4%. By iterative retrogradation, the internal structures of amylosucrase-treated starch crystallites were altered to exhibit increased heat stabilities and perfections. In regards to in vitro digestibility, iteratively retrograded amylosucrase-treated starches showed higher RS content and lower RDS content compared with amylosucrase-treated starch. However, the dramatic changes in thermal transition properties, relatively crystallinity, and in vitro digestibility occurred during the first cycle of retrogradation and further retrogradation cycle did not affect them.

Photovoltaic Effect in BiFeO₃ Film Deposited by RF Magnetron Sputtering.

A polycrystalline BiFeO₃ film was deposited on ITO substrate by RF magnetron sputtering method. Small crystallite size and compact structure are obtained for BiFeO₃ film which has the excellent ferroelectric properties. The measured photovoltaic response reveals an open-circuit voltage of ~0.52 V and a short-circuit current density of ~10 μA/cm² under the illumination of 100 mW/cm² irradiance. Moreover, a tunable photovoltaic effect with light illumination is observed under different voltage sweep mode. High initial sweep voltage can enhance the photovoltaic effect largely, however, the photovoltaic response decreases with the increase of voltage sweep interval. The results indicate the ferroelectric polarization plays an important role in the photovoltaic effect.

Complex oxides of copper and manganese as the base material for catalytic suppression of waste gases

The composite material “ionite-sorbed ions” was obtained by ion exchange technology. The conditions for obtaining the composite material “ionite-sorbed ions” are studied. In the thermolysis of cationite with sorbed ions, the synthesis of complex oxide is carried out between ions located at atomic distances from each other. This facilitates and accelerates the formation of complex oxide. Thermolysis of carboxyl cationite KB-4P-2 with sorbed copper and manganese ions was performed at temperatures from 250-950°C . Control of the thermolysis mechanism of the composite material “ionite-sorbed ions” was carried out using thermograms. According to the scanning electron microscopy data, the obtained powder of complex copper and manganese oxide has a good crystallite structure. Data x-ray diffraction analysis confirmed the crystallization of a complex oxide of copper and manganese in orthorhombic crystal structure. A method for the synthesis of complex copper and manganese oxide powder based on the thermolysis process of the composite material “ionite-sorbed ions”, which has catalytic properties, has been developed.

Investigation of Organic Field-Effect Transistor (OFET) based NO2 Sensing Response using Low-Cost Green Synthesized Zinc Oxide Nanoparticles

A low-cost and green-synthesized zinc oxide nanostructured particles are extensively studied owing to their remarkable and ample characteristics with less toxicity and eco-friendly approach. The present work comprehends the green synthesis of ZnO nanostructured particles using bougainvillea leaf extract-arbitrated microwave-assisted synthesis and their use in field effect transistor for nitrogen dioxide sensing at room temperature. The as-synthesized nanoparticles were characterized using analytical techniques; XRD determined the pure crystallite structure with no impurities, SEM confirmed the spherical shape of nanoparticles with ~20 nm (average particle size) and the atomic weight percentage were analyzed using EDAX, notable photophysical properties were revealed from absorption and emission spectra performed using UV-visible spectroscopy. Poly(3-hexylthiophene) and ZnO nanoparticles were employed in the field effect transistor (p-type) for NO2 sensing at room temperature with the mobility (field-effect) of ~10-4 cm2 V-1 s-1. The sensitivity of the fabricated OFET device was extracted from the transistor characteristics (at Vgs = -30 V and Vds = -40 V) found to be ~4.8 × 10-3 nA/ppm. The device exhibited engrossing characteristics such as excellent recoverability (> 95%), with ultrafast response time (< 30 s) and greater sensitivity with high stability as can be assessed from the electrical characteristics.

Synthesis and characterization of Mg doped TiO2 nanoparticles for photocatalytic applications

Undoped and Mg-doped (0.3 and 0.4 M) TiO2 nanoparticles were synthesized by the sol–gel technique. X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM) were used to characterize the crystallite structure and morphology of TiO2 nanoparticles. The crystallite size varies from 8.11 to 27.17 nm when Mg content increases from 0 to 0.4 M. UV-DRS studies show the occurrence of strong blue shift and broad absorption show incorporation of Mg in TiO2 lattices. The bandgap values were found to be decreased from 3.02 to 2.87 eV when the Mg content increases from 0 to 0.4 M. From the PL analysis, the emission spectra were recorded for the prepared samples. The Ti, O and Mg were identified from the EDS spectra. Photocatalytic degradation of methyl orange was also analyzed using the synthesized nanoparticles acts as a catalyst.

Systematic investigation of CO2 : NH3 ice mixtures using mid-IR and VUV spectroscopy - part 1: thermal processing.

The adjustment of experimental parameters in interstellar ice analogues can have profound effects on molecular synthesis within an ice system. We demonstrated this by systematically investigating the stoichiometric mixing ratios of CO2 : NH3 ices as a function of thermal processing using mid-IR and VUV spectroscopy. We observed that the type of CO2 bonding environment was dependent on the different stoichiometric mixing ratios and that this pre-determined the NH3 crystallite structure after phase change. The thermal reactivity of the ices was linked to the different chemical and physical properties of the stoichiometric ratios. Our results provide new details into the chemical and physical properties of the different stoichiometric CO2 : NH3 ices enhancing our understanding of the thermally induced molecular synthesis within this ice system.

Dielectric Properties of Multi-Layers Hexagonal Boron Nitride

A higher value of the dielectric constant of h-BN makes it quite favourable material in energy storing device. The variation in dielectric constant was observed as a function of thickness. In this research work multilayers of Hexagonal Boron Nitride (h-BN) was fabricated by using the Chemical exfoliation method. Two solvents Dimethylformamide (DMF) and Isopropyl Alcohol (IPA) were used for the exfoliation of h-BN. Successful sonication of hexagonal boron nitride led to the formation of Boron Nitride nanosheets (BNNs). The stable dispersibility of h-BN in Dimethylformamide and Isopropyl Alcohol was confirmed by UV Visible Spectroscopy, X-ray diffraction (XRD) and Scanning electron microscopy (SEM) confirm the mono crystallite structure (002) and nanoflakes like morphology of h-BN respectively. This appropriate strategy offered a feasible route to produce multilayer of hexagonal boron nitride. After the successful fabrication of h-BN multilayers its dielectric properties were calculated by using LCR meter. Profilometer revealed the variation in thickness and value of Dielectric constant was calculated by using its formula.

Synthesis and Electrochemical Characterisation of Novel Hybrid Copper / Poly (diphenylamine) (PDPA) Nanocomposites

The Poly (diphenylamine) (PDPA) nanoparticles was synthesized by surfactant assisted dilute polymerization method and characterized by UV-Visible, FTIR and Cyclic Voltammetry techniques. The PDPA nanoparticles were then suspended in an acidified copper sulphate electrolytic bath to prepare Cu-PDPA nanocomposites by simple electrodeposition technique. The XRD analysis revealed that the crystallite structure of Cu-PDPA nanocomposites and pure copper coatings was crystalline fcc and the grain size was 32 nm for pure Cu and 27 nm for Cu-PDPA nanocomposites. This decrease in crystallite size of Cu-PDPA nanocomposites shows the inclusion of PDPA nanoparticles was uniformly distributed throughout the copper matrix. The microstructure of the Cu-PDPA nanocomposites was examined by SEM analysis shows cauliflower like crystallites with layer by layer outward growth compared to electrodeposited pure copper coatings. The Electrochemical AC impedance and Tafel polarization studies were performed for electrodeposited copper and Cu-PDPA nanocomposites in 3.5% NaCl solution. It revealed that the Cu-PDPA nanocomposite coatings were found to be more corrosion resistance than electrodeposited pure copper coating.

In Ukrainian

The prevalence of Cerium compounds, economic affordability, and unique redox properties determine the wide range of cerium oxide applications. The transition to nanosized particles of cerium oxide allows these materials to reversibly absorb and release oxygen, which determined the use of nano-CeO2 in biomedical technologies in the treatment of diseases associated with lesions due to oxidative stress. The review analyzed the state of modern scientific literature regarding the properties, methods for producing and using cerium nanooxide. The main characteristics of cerium oxide and the features of its structure are described, the mechanisms of action of the enzyme-like properties of nanoceria are given. It was shown that the coexistence of Ce3+ and Ce4+ ions on the surface is compensated by the formation of oxygen vacancies, which are essentially surface defects. Their number depends on the particle size, morphology and crystallinity of the material. These surface defects are catalytic centers that are capable of exhibiting the enzyme-like properties of nanoceria and effectively absorbing free radicals, which include reactive oxygen species. Physicochemical properties of nanoparticles depend on the synthesis parameters. These include the nature and type of precursor, stabilizing agent and solvent, the duration and temperature of the reaction, and the pH of the reactive mixture. So, microgravity affects morphology, average particle size, crystallinity; an increase in the aging time leads to the synthesis of large particles and crystallites, increases the degree of crystallinity. The synthesis temperature affects the size and structure of crystallites, agglomeration, surface defects and oxidation state. Varying the synthesis parameters and their control during the reaction allows one to obtain particles with desired physicochemical properties. The main methods are analyzed in detail: deposition, hydrothermal, microemulsion, combustion, sol-gel and green. It has been established that, due to its unique properties, nanosized cerium oxide has a wide range of applications. It is used as an abrasive powder for polishing glass and protecting it from corrosion; commercial sunscreens are produced on its basis, biosensors and solid oxide fuel cells are constructed, and catalysts are synthesized. Cerium oxide nanoparticles and materials based on it are widely used in environmental, industrial, bioanalytical and biomedical fields. Recently, the biomedical use of nanosized cerium oxide has been rapidly developing. The non-stoichiometric composition of cerium oxide nanoparticles allows it to effectively neutralize reactive oxygen species while protecting the body from oxidative stress. Nano-CeO2 is used in the treatment of inflammatory, cardiovascular and neurodegenerative diseases, it increases the activity of antimicrobials, is an agent for the delivery of therapeutic drugs to cancer cells.

Nano SiC Reinforced Copper Nanocomposite by a Simple Electrodeposition Method

The Cu and Cu-SiCnanocomposite coatings were prepared by a simple electrodeposition technique from acidic copper sulphate electrolyte using SiC nanoparticles with an average particles size of 50 nm under optimized bath composition and preparation conditions for possible electrical contact material applications such as electrical switch and wiring boards where higher electrical conductivity and thermal conductivity is required. The scope of the present study is to enhance the strength, mechanical, corrosion and wear resistance properties of Cu-SiCnanocomposite compared to pure Cu coatings. The as prepared Cu and Cu-SiCnanocomposites were characterized for structural, mechanical and corrosion resistance properties by EDX, XRD, FESEM, Vickers microhardness tester and AC-impedance and Tafel polarization techniques. The elemental composition (wt% of Cu and SiC nanoparticles) of Cu-SiCnanocomposites was analyzed by EDX coupled with FESEM analysis confirms the presence of nanoSiC in the copper matrix and they were 89wt% of Cu and 11 wt% of SiC nanoparticles respectively. The surface morphology of Cu and Cu-SiCnanocomposites was studied by FESEM analysis shows that SiC nanoparticles were uniformly dispersed in the surface of the copper matrix compared to pure copper. The crystallite structure and grain size of the Cu and Cu-SiCnanocomposite electrodeposits was measured by XRD analysis. From the XRD results, the grain size calculated using Debye-Scherrer’s formula was ~35 nm for pure Cu and ~33 nm Cu-SiCnanocomposite. The crystallite structure of Cu and Cu-SiCnanocomposites was fcc (face centered cubic) and the preferred orientation of the plane was (220). The microhardness of Cu-SiCnanocomposite coating increased with increasing SiC nanoparticles concentration in the bath compared to pure Cu coating. The corrosion resistance measurements were performed for the pure Cu and Cu-SiCnanocomposite coatings by electrochemical impedance spectroscopy (EIS) and Tafel polarization techniques. It shows that, Cu-SiCnanocomposites has high corrosion resistance than pure Cu in 3.5wt% NaCl solution.

Shape-Stabilized Phase Change Materials for Solar Energy Storage: MgO and Mg(OH)2 Mixed with Polyethylene Glycol.

Heat energy storage systems were fabricated with the impregnation method using MgO and Mg(OH)2 as supporting materials and polyethylene glycol (PEG-6000) as the functional phase. MgO and Mg(OH)2 were synthesized from the salt Mg(NO3)·6H2O by performing hydrothermal reactions with various precipitating agents. The precipitating agents were NaOH, KOH, NH3, NH3 with pamoic acid (PA), or (NH4)2CO3. The result shows that the selection of the precipitating agent has a significant impact on the crystallite structure, size, and shape of the final products. Of the precipitating agents tested, only NaOH and NH3 with PA produce single-phase Mg(OH)2 as the as-synthesized product. Pore size distribution analyses revealed that the surfaces of the as-synthesized MgO have a slit-like pore structure with a broad-type pore size distribution, whereas the as-synthesized Mg(OH)2 has a mesoporous structure with a narrow pore size distribution. This structure enhances the latent heat of the phase change material (PCM) as well as super cooling mitigation. The PEG/Mg(OH)2 PCM also exhibits reproducible behavior over a large number of thermal cycles. Both MgO and Mg(OH)2 matrices prevent the leakage of liquid PEG during the phase transition in phase change materials (PCMs). However, MgO/PEG has a low impregnation ratio and efficiency, with a low thermal storage capability. This is due to the large pore diameter, which does not allow MgO to retain a larger amount of PEG. The latent heat values of PEG-1000/PEG-6000 blends with MgO and Mg(OH)2 were also determined with a view to extending the application of the PCMs to energy storage over wider temperature ranges.

Modification in ZnO film properties by 250 keV cobalt implantation

Direct current magnetron sputtering technique was used to synthesize ZnO films on PET (Polyethylene terephthalate) substrate. The as-synthesized films were exposed to 250 keV cobalt (Co) ions by Pelletron Accelerator at different ion fluences (in range of 1011 to 1014 ions cm−2). The lattice constant, crystallite structure, size and strain of pristine and Co-implanted films were studied through x-ray diffraction (XRD) method. The study showed that the ZnO film became partially amorphous after Co implantation up to the fluence of 1013 ions cm−2. However, Co implantation at 1014 ions cm−2 slightly restored the film’s crystallinity due to ion-induced localized heating. Tauc equation was used to estimate the band gap of pristine and Co implanted films. The band gap of Co implanted ZnO was decreased by increasing the ion fluence that was ascribed to a decrease in the conduction band tail due to overlapping of donor defect levels. Electrical measurements showed that the ZnO film became more conductive with increasing the Co fluence.