Modification of ZnO/Perlite for Methylene Blue Photodegradation

Objective: Nanotechnology enhances the solubility, bioavailability and the rate of solubility of drugs whose solubility of water is very weak. The primary goals of creating nanocrystals are to enhance the bioavailability of weakly soluble drugs, streamline the administration of Metaxalone (MTX) via the all routes and enhance solubility and pharmacokinetic performance. Material and Methods: The solvent diffusion approach was utilized to create drug nanocrystals without surfactants by employing stabilizers such cyclodextrin (CD). A cooling centrifuge was utilized to perform high-speed centrifugation in order to separate the nanocrystal from the nanosuspension. Differential scanning calorimetry (DSC), electron microscopy (SEM), FTIR analysis, powder X-ray diffraction analysis, solubility analysis, Particle size range and zeta potential measurement, in-vitro dissolution and ex-vivo permeation study were used to evaluate and characterized the results. Results: MTX nanocrystal formulation 8 (MNC 8) has better solubility than MNC 7. The nanocrystal was created in MNC 7, MNC 8, and MNC 9, according to the z-average values 448 to 11850nm and zeta potential value for MNC 8 and MNC 7 was found -8.62±3.99 and -10.4±9.13. FTIR spectrum of MNC 8, characteristic peaks that were seen at 3441, 1733, 1082, 3602, 2922, 1641 and 2354 cm-1. In its crystal state, MNC 8 diffraction angles were determined to be 5.01, 10.25, 13.34, 14.18, 17.87, 19.03 and 22.40º. The endothermic peak of DSC at 124ºC confirms the observed melting point of MTX, which is 121ºC. According to DSC thermograms, the melting point range was 120-125ºC. Drugs demonstrated 11% membrane penetration at 1 hour, but MTX permeability through MTX nanocrystals was 15-17%. Better MTX nanocrystal solubility was confirmed at 6 hours with a 46% drug release in MTX solution and a 58-65% drug release in the formulation. MNC 8 exhibited a higher drug content than MNC 7 and MNC 9 among the formulations. Conclusion: Franz diffusion cell apparatus used a biological membrane (egg cell membrane) to conduct an ex-vivo drug release research of MTX and MTX nanocrystal. Compared to pure MTX, formulated MTX nanocrystal exhibits superior drug release.

To study the effect of Nd:YAG laser on the properties of structural and optical values of the energy gap of cadmium oxide (CdO) films, have been prepared using chemical spray pyrolysis and deposited on a glass substrate for concentrations(0.05, 0.1, 0.15)M at temperature (350°C) ,using 6 spray rate during (10) second for each spray . To study the optical properties of the film Prepared (CdO) before and after irradiation Nd:YAG laser with energy (200) mJ at different times (5,10,15)sec and at (1) meter far from the source using a(UV-Visible) spectrometer device and the extent of wavelengths, (300-1100) nm the results showed that the energy gap increased with increasing concentrations and was the ideal value when the concentration of (0.1)M, where the value of energy gap is (2.25)eV, but after laser irradiation redueced to (2)eV. The Atomic Force Microscope(AFM) has been used to study the structural properties of the composition and topography of the surface in two and three dimensions of the films prepared before and after irradiation, the results indicate that the surface rate roughness and the average root of the square less after irradiation, and it is observed ideal value for this property is at a concentration of (0.1)M. The crystalline structures and surface morphology of CdO thin film examined by XRD analysis. The result showed the films are polycrystalline for and crystalline granules prevailing levels of growth are at (220), (200), (111) the irradiation led to a slight change in the angle of diffraction in the lattice constants (a) and a decline in giving the peak tops.

The thermal vacuum evaporation technique is utilized to prepare two novel, uniform and compact thin films of quinoxaline 1,4dioxide derivatives: 6-Chloro-3-(hydrazinecarbonyl)-2-methylquinoxaline 1,4-dioxide (CHMQ) and 6-Chloro-2-methyl-3-(2-(4-nitrbenzylidene)hydrazine-1-carbonyl) quinoxaline 1,4-dioxide (CMNQ). The structures of thin films are characterized using Fourier transform infrared spectrophotometry, X-ray diffraction and atomic force microscopy techniques. The theoretical vibrational frequencies and optimized geometric parameters (bond lengths, and bond angles) and the theoretical energy gap (HOMO–LUMO optical gap) values of the CHMQ and CMNQ compounds are also calculated. Crystalline structures, lattice parameters, Miller indices, diffraction angles and interplaner spacings for both compounds, in their powder form, are computed. Crystallite size, dislocation density and microstrain values are calculated for CHMQ and CMNQ thin films. Several optical constants like refractive index and absorption index of CHMQ and CMNQ thin films are calculated from the absolute values of their transmittance and reflectance spectra measured by a spectrophotometric method. The absorption parameters such as the type of electronic transition and the optical band gap values of the thin films are estimated and showed a good agreement with the corresponding theoretical energy gap values. The dispersion parameters (oscillator energy, dispersion energy, high frequency dielectric constant, lattice dielectric constant and ratio of free charge carriers’ concentration to its effective mass) of the thin films are estimated using single oscillator model in the non-absorbing region of each spectrum. The dielectric properties and the optical conductivity of the thin films are also determined.

Single phase CuInS<TEX>$_2$</TEX> thin film with the strongest diffraction peak (112) at diffraction angle (2<TEX>$\theta$</TEX>) of 27.7<TEX>$^{\circ}$</TEX> and the second strongest diffraction peak (220) at diffraction angle (2<TEX>$\theta$</TEX>) of 46.25<TEX>$^{\circ}$</TEX>was well made with chalcopyrite structure at substrate temperature of 70<TEX>$^{\circ}C$</TEX>. annealing temperature of 250<TEX>$^{\circ}C$</TEX>, annealing time of 60 min. The CuInS<TEX>$_2$</TEX> thin film had the greatest grain size of 1.2 Um when the Cu/In composition ratio of 1.03, where the lattice constant of a and c were 5.60<TEX>${\AA}$</TEX> and 11.12<TEX>${\AA}$</TEX>, respectively. The Cu/In stoichiometry of the single-phase CuInS<TEX>$_2$</TEX>thin films was from 0.84 to 1.3. The film was p-type when tile Cu/In ratio was above 0.99 and was n-type when the Cu/In was below 0.95. The fundamental absorption wavelength, absorption coefficient and optical band gap of p-type CuInS<TEX>$_2$</TEX> thin film with Cu/In=1.3 were 837nm, 3.OH 104 cm-1 and 1.48 eV, respectively. The fundamental absorption wavelength absorption coefficient and optical energy band gap of n-type CuInS<TEX>$_2$</TEX> thin film with Cu/In=0.84 were 821 nm, 6.0<TEX>${\times}$</TEX>10<TEX>$^4$</TEX>cm<TEX>$\^$</TEX>-1/ and 1.51 eV, respectively.

Nickel ferrite nanoparticles are prepared by using a low-temperature self-propagating solution combustion method using urea as fuel. The prepared nickel ferrite nanoparticles were doped with polyaniline in the three different weight ratios of 10%, 30% and 50% by using an in situ polymerization method and by adding ammonium persulfate as an oxidizing agent. The obtained samples were characterized by using XRD, FTIR, SEM and a UV-visible spectrophotometer. XRD examined crystalline peaks of ferrites and amorphous peak of polyaniline and confirmed the formation of the composites. FTIR examined the chemical nature of samples and showed peaks due to polyaniline and the characteristic peaks that were less than 1000 cm-1 wavenumber were due to metal-oxygen bond vibrations of ferrites. AC conductivity increased with frequency in all samples and the highest AC conductivity was seen in polyaniline/nickel ferrite 50%. DC conductivity increased in all samples with the temperature showing the semiconducting nature of the samples. Activation energy was evaluated by using Arrhenius plots and there was a decrease in activation energy with the addition of ferrite content. The UV-visible absorption peaks of polyaniline showed shifting in the composites. The optical direct and indirect band gaps were evaluated by plotting Tauc plots and the values of the optical band gap decreased with addition of ferrite in polyaniline and the Urbach energy increased in the samples with 10%, 30% and 50% polyaniline/nickel ferrite composites. The optical properties of these composites with a low band gap can find applications in devices such as solar cells.

Band gap engineering of tandem structured CIGS compound absorption layer fabricated by sputtering and selenization

Hafnium oxide (HfO2) thin films have been made by atomic vapor deposition (AVD) onto Si substrates under different growth temperature and oxygen flow. The effect of different growth conditions on the structure and optical characteristics of deposited HfO2 film has been studied using X-ray photoelectron spectroscopy (XPS), Rutherford backscattering spectrometry (RBS), grazing incidence X-ray diffraction (GIXRD) and variable angle spectroscopic ellipsometry (VASE). The XPS measurements and analyses revealed the insufficient chemical reaction at the lower oxygen flow rate and the film quality improved at higher oxygen flow rate. Via GIXRD, it was found that the HfO2 films on Si were amorphous in nature, as deposited at lower deposition temperature, while being polycrystalline at higher deposition temperature. The structural phase changes from interface to surface were demonstrated. The values of optical constants and bandgaps and their variations with the growth conditions were determined accurately from VASE and XPS. All analyses indicate that appropriate substrate temperature and oxygen flow are essential to achieve high quality of the AVD-grown HfO2 films.

The gadolinium substituted nickel-zinc ferrite nanoparticles of the composition, Ni0.5Zn0.5Gd0.05Fe1.95O4 were prepared using sol-gel method. In order to study the effect of calcination temperature on the optical parameters, the prepared powder was divided into five parts. The first part was taken as the as-prepared sample and the remaining four parts were calcinated at different temperatures, 600°C, 700°C, 800°C & 900°C. The X-ray diffraction patterns revealed the formation of cubic spinel structure with single phase and Fd3m space group. The crystallite size was increased from 11.75 nm to 18.13 nm as the calcination temperature increased from 600 to 900°C whereas as-prepared sample exhibited 17.61 nm. The dislocation density was decreased from 7.243 × 10-3 to 3.042 × 10-3 nm-2 as the calcination temperature increased from 600°C to 900°C. The micro strain was decreased from 10 × 10-4 to 6.452 × 10-4 as the calcination temperature increased from 600°C to 900°C. The characteristic absorbance peaks were obtained at 255.2 nm for the ferrite nanoparticles of as-prepared and calcinated at 600°C and 800°C whereas it was obtained as 252.8 nm for the sample calcinated at 700°C and there was no such characteristic peak in UV-visible range for the sample calcinated at 900°C; it is expected in the below 200 nm region. The optical energy gap was calculated using Kubelka-Munk equation based on Tauc’s plot and found in the range 4.100 eV to 5.389 eV. The lowest energy gap of 4.100 eV exhibited by the sample calcinated at 700°C and the highest energy gap of 5.389 eV by the sample calcinated at 900°C. It is concluded that the tunable band gaps can be obtained with varying calcination temperature.

The pillarization of Mg/Al double layer hydroxides using polyoxometalate H3[α-PW12O40]·nH2O by comparing the pillarization time i.e. 3 hours, 6 hours, 9 hours, 12 hours, 24 hours, 36 hours and 48 hours has been done. The product of a pillarization was characterized using an FT-IR spectrophotometer and XRD analysis. The result characterization of FT-IR spectrophotometer does not show the optimum of pillarization each time condition. Characterization using XRD shows the optimum pillarization process at 36 hours by showing the existence of double layer hydroxides material at diffraction angle 11.69o deg, 18.30o deg and 34.71o deg. Diffraction in the 60o-63o deg indicates the existence of a pillarization double layer hydroxides. Keywords: Layered double hydroxides, pillarization, polyoxometalate H3[α-PW12O40]·nH2O.

Microstructural, surface and electrochemical properties of pulse electrodeposited Ni–W/Si3N4 nanocomposite coating

Synthesis and Characterization of PMMA Adherent ZnS thin Films by Spin Coating Method

Hetero-valent cations-doped zinc stannate nanoparticles for optoelectronic and dielectric applications

Earth abundant and ecofriendly zinc sulphide (ZnS) is a direct wide band gap semiconductor material and applications of ZnS thin-films cover a large area including optoelectronic devices. As thin-films of ZnS are highly defective depending on fabrication process, prior to final target applications, properties of thin-films should be studied first. This study was motivated to apply ZnS thin-film as an alternative buffer layer in a chalcogenide based multilayer thin-film solar cell (TFSC) e.g. CZTS using a reliable and clean deposition technique. This study reports mainly on optical properties of ZnS thin-films with varying substrate temperatures. ZnS thin-films were deposited on soda lime glass (SLG) substrates using radio frequency (RF) magnetron sputtering. Room temperature (RT), 150° C, 300° C were taken as substrate temperature variants with RF power and argon (Ar) flow rate remained fixed at 100W and 20 SCCM respectively for all depositions. Structural properties were confirmed by XRD and optical properties were probed by UV-Vis NIR spectroscopy. It was found from structural studies that most of the films were crystallographically cubic type lattice, oriented along (111) plane with Bragg's diffraction angle at 28.95°. The average optical transmittance were found around 87% (invisible and near infrared regions of spectrum). The optical band gaps as obtained were in decreasing nature from 3.96eV to 3.71eV as substrate temperature increased from room temperature to 300°C, were in good agreement with Urbach energy analysis. Although the findings of optical properties are potentially positive, prior to apply ZnS thin-film as a buffer layer in full TFSC fabrication, more investigations will be required on electrical and morphological properties with the same investigated recipe.

Boosting the stability and growth of methylammonium lead bromide perovskites film doped with FA for solar cells

In this work, GaN-NWs were synthesized via vapor-liquid–solid (V-L-S) mechanism by chemical vapor deposition (CVD) technique using different metal catalysts, N2 and H2 flow rates. The (101) plane of GaN-NWs grown with Ni catalyst shift to higher diffraction angle indicates tensile stress whereas with Fe catalyst it shifts to lower diffraction angle indicates compressive stress. The FTIR spectrum of GaN-NWs grown with Ag, Fe, Ni and In catalysts revealed that 2E1(TO) peak shows asymmetry to higher wavenumber region indicate another chemical compound of Ga=N or Ga–N–O with similar bonding strength overlap with each other. Raman spectrum of GaN-NWs with Ag, Fe, Ni, and In catalyst varying H2 flow rates confirms that the intensity of A1(TO) phonon peak with Ag catalyst increases with increasing H2 flow rate indicates increasing polarizability of GaN-NWs due to change in dielectric constant of surrounding chemical environment. We have observed shorter phonon lifetime with Ni catalyst whereas longer phonon lifetime is observed with Fe catalyst. The room temperature photoluminescence spectra of GaN-NWs reveal several emission bands centered at 2.54, 2.69, 2.81, 2.89, and 2.94 eV, respectively. The integrated PL peak intensity decreases with increasing excitation energy above band gap indicates the non uniform distribution of defect states. XPS spectra of GaN-NWs reveal the presence of Ga(3d), Ga(3p), Ga(3s), C(1s), N(1s), at 20.3, 110.4, 162, 276, 398.3 eV, respectively.