Imaginary Dielectric Constants Research Articles

A study of the Electrical and Dialectical proprieties of S60-Se40-X-PbX Chalcogenide Compound

In this study, the melting-cooling method was used to prepare the chalcogenide compound S60-Se40-X-PbX. Four samples were obtained by partial replacement of Selenium with Lead in the weight ratios x = 0, 10, 20, and 30, respectively. The materials were mixed separately, ground, placed in quartz ampoules, and heated to 500 degrees Celsius. After conducting several operations on the samples, their insulating properties were studied, represented by the real dielectric constant and the imaginary dielectric constant, and the electrical conductivity was measured as a function of the frequency. It was found that partial replacement plays an important role in enhancing the insulating properties. It was found that partial replacement of selenium with lead led to a change in the insulating properties and alternating electrical conductivity.

Innovative soil fluoride estimation method: dual polarimetric saline-associated fluoride for agricultural patches.

Fluoride and its constituents in soil affect plant growth and public health. In this study, soil fluoride was measured for the semi-arid regions in southern India, using Sentinel-1 data in conjunction with the dual polarimetric saline-associated fluoride model (also known as fluoride model). A loss angle was estimated from laboratory-based dielectric components of soil samples with strong electrical conductivity under high and low fluoride conditions. The conductivity loss angle and real and imaginary dielectric constants were used to study fluoride salt's dielectric behavior. The imaginary dielectric component sensitive to dielectric loss could predict fluoride across large areas over time. This was statistically analyzed with R2 = 0.86, RMSE = 1.90, and bias = 0.35 showing a promising depiction that C-band SAR data can distinguish fluoride levels over varied clay soil and soil with varying vegetation development. Moreover, the association between biomass and simulated fluoride helped to identify fluoride-tolerant and non-tolerant crops. The study found that Sorghum and Oryza sativa tolerate saline-associated fluoride, whereas Peanut and Allium do not. Furthermore, the model successfully retrieves fluoride from saline salts based on tangent loss.

Optical characterization and dispersion analyses of plasma polymerized methyl acrylate thin films

This work reports the structural characteristics, surface morphology, linear and nonlinear optical properties of 110 to 225 nm thick plasma polymerized methyl acrylate (PPMA) thin films. X-ray diffraction analyses confirm the amorphous nature of the films. Field emission scanning electron micrographs of the films display cluster-based surface morphology. Attenuated total reflectance Fourier transform infrared spectroscopy confirms the chemical structural changes in the films. The optical properties were studied based on the absorbance, transmittance, and reflectance spectra measured by an ultraviolet–visible spectrophotometer within the wavelength ranges from 200 to 800 nm. The direct optical band gap and Urbach values are increased from 3.66 to 3.83 eV and 0.28 to 0.45 eV, respectively with increasing film thickness. The extinction coefficient and refractive index were evaluated, and discussed a correlation between the refractive index and the optical bandgap. The real and imaginary dielectric constants, volume/surface energy loss functions and skin depth were deduced. The oscillator energies and parameters were analyzed using the concept of Wemple-DiDomenico and Sellmeier models, respectively for a single oscillator. Static linear refractive index for the studied films exhibits normal dispersion behavior with film thicknesses and satisfied Moss, Ravindra-Gupta, and Herve-Vandamme rules. The linear susceptibility, third-order nonlinear susceptibility and the non-linear refractive index are considerably reduced from 0.20, 29.5 × 10−14 esu, and 5.89 × 10−12 esu with increasing optical band gap energies. The outcomes from the analyses of PPMA demonstrated their potential for usage in electronic, optoelectronic, and non-linear device applications.

Optical and optoelectronic properties of gallium oxide films fabricated by the chemical vapour deposition method

The present work investigated the influence of growth time on the structural, optical, and optoelectronic properties of β-Ga2O3 films produced on Si substrates by the chemical vapour deposition method. The prepared films were characterized by X-ray diffraction, field-emission scanning electron microscope, and UV–Vis spectrophotometer. The films exhibited a mixed phase (β-α)-Ga2O3 crystal structure. The crystallite size ranged between 34.98 and 164.69 nm. The bandgap increased from 4.74 to 4.88 eV. The absorption and extinction coefficients were in the orders of 103 and 10−1, respectively. The refractive index, dispersive energy and single oscillator energy increased from 1.86 to 1.87, 19.24 to 28.64, and 8.36 to 9.54, respectively, with an increase of growth time. The oscillator strength, oscillator wavelength, third-order nonlinear optical susceptibility and dispersion of refractive index were in the orders of 10−4, 10−2, 10−10 and 10−9, respectively. The carrier concentration, optical conductivity, optical mobility, and optical resistivity were also evaluated. The real and imaginary dielectric constants, and plasmon frequency were also determined.

Growth mechanism, structure, stoichiometry and optical properties of electrochemically grown iron selenide and ferroselite thin films

In this present work, FeSe and FeSe2 thin films were deposited on ITO substrate at different electrolytic bath temperatures at 30 °C and 70 °C by using electrodeposition method. The growth mechanism was investigated via cyclic voltammetry with the potential window was found to be −1600 to 1600 mV versus SCE and the formation of well adherent film was found to be higher bath temperature. XRD result shows the deposited FeSe and FeSe2 films found to exhibit stoichiometric wurtzite and orthorhombic phases respectively. The microscopic observation shows, the uniform particle growth of FeSe and FeSe2 was found to be higher electrolytic bath temperature at 70 °C. The EDX analysis shows the deposited FeSe and FeSe2 films at higher temperature elemental is stoichiometric ratio. The determined bandgap values for FeSe (1.26 eV) and FeSe2 (1.07 eV) deposited at 70 °C. Also, we observed that the refractive indices (n) values was increased for the film deposited from 30 °C to 70 °C resulting, the estimated refractive indices (n) for FeSe and FeSe2 are 3.16 and 3.45 respectively. Furthermore the most significant optical parameters extinction coefficient (k), optical conductivity (σoptical), real (Ɛ1) and imaginary (Ɛ1) dielectric constants and dissipation factor (tan δ) are determined in order to investigate their usefulness in photovoltaic applications.

Influence of the content of stacked ZnO on the structural and optical properties of heterostructured ZnO/Ga2O3 films

The rising demand for heterojunction materials stimulated by the great achievements of modern nanotechnology has triggered enormous interests in the investigation of their materials properties. Heterostructured ZnO/Ga2O3 has been deployed for different device applications, but its several optical parameters have rarely been investigated. The present work attempts to investigate the influence of the thickness of stacked ZnO layer on the surface of Ga2O3 film. Optical parameters, such as absorption and extinction coefficient, Urbach energy, refractive index, dielectric constants, optical dispersion energy, single oscillator energy, static refractive index, oscillator strength, and oscillator wavelength of the ZnO/Ga2O3 films were studied. Morphological characterization showed microstructures of various shapes. Cross-section measurements showed that the thickness of the Ga2O3 layer remained approximately the same for all samples, while the thickness of the ZnO layer increased from 0 to 5.14 nm. Structural analysis revealed the coexistence of β-Ga2O3 and wurtzite ZnO crystal phases. UV–Vis absorption spectra demonstrated two distinct absorptions belonging to the β-Ga2O3 and ZnO. The bandgap of the composite ranged between 4.43 and 4.69 eV with an increase in the amount of ZnO at the surface. The absorption and extinction coefficient were in the order of 103 cm−1 and 10−5, respectively. The Urbach energy ranged between 0.688 and 1.125 eV. The refractive index was in the range 2.09–2.85, while the static refractive index ranged between 1.90 and 2.73. Also reported were other optical parameters, such as the real and imaginary dielectric constant, dispersive energy, single oscillator energy, oscillator strength, and oscillator wavelength.

Synthesis, microstructural and optical characterizations of sol-gel grown gadolinium doped cerium oxide ceramics.

In this study, through the utilization of the sol-gel combustion tactic, gadolinium (Gd)-doped cerium oxide (CeO2), Ce1-xGdxO2 (x = 0.00, 0.10, 0.20 and 0.30 (GDC)) ceramics were attained. The synthesized GDC ceramics were investigated using X-ray diffraction (XRD) to scrutinize their crystal structures and phase clarities. The obtained GDC ceramics have a single-phase cubic structure and belong to the crystallographic space group fm3̄m (225). The measurement of the diffraction angle of each reflection and the subsequent smearing of the renowned Bragg's relation provided coarse d-interplanar spacings. The stacking fault (SF) values of pure and Gd-doped CeO2 ceramics were assessed. To muse the degree of preferred orientation (σ) of crystallites along a crystal plane (h k l), the texture coefficient (Ci) of each XRD peak of GDC ceramics is gauged. By determining the interplanar distance (dh k l), the Bravais theory sheds light on the material's development. By exploiting Miller indices for the prime (1 1 1) plane, the lattice constants of GDC ceramics and cell volumes were obtained. Multiple techniques were employed to ascertain the microstructural parameters of GDC ceramics. A pyrometer substantiated the density of GDC ceramics. The room temperature (RT) Fourier transform infrared (FTIR) spectra of both un-doped and Gd-doped CeO2 were obtained. The UV-vis-NIR spectrometer recorded the GDC ceramics' reflectance (R) spectra at RT. For both undoped and Gd-doped CeO2, the absorption coefficient (α) spectra showed two distinct peaks. The R-dependent refractive index (η) and the α-dependent extinction coefficient (k) were determined for all GDC samples. The optical band gap (Eg) was obtained by integrating the Tauc and Kubelka-Munk approaches for GDC ceramics. For each GDC sample, the imaginary (εi) and real (εr) dielectric constants, as well as the dissipation factor (tan δ), were determined local to the characteristic wavelength (λc). Calculations were made for the Urbach energy (EU) and Urbach absorption coefficient (α0) for GDC ceramics. The minimum and maximum values of optical (σo) and electrical (σe) conductivity for GDC ceramics were determined. The volume (VELF) and surface (SELF) energy loss functions, which depend on the constants εi and εr, were used to measure electrons' energy loss rates as they travel across the surface. Raman spectroscopy revealed various vibrational modes in GDC ceramics. Finally, the implications are discussed herein.

An ab‐initio study of structural, opto‐electronic and thermoelectric aspects of zinc sulfide and zinc telluride

AbstractIn this study, structural, electronic, optical and thermoelectric aspects of Zinc Sulfide (ZnS) and Zinc Telluride (ZnTe) have been explored in detail. These calculations have been done by utilizing FP‐LAPW method via Density Functional Theory (DFT). In order to attain accurate band gaps, opto‐electronic properties are evaluated with modified Becke Johnson potential (mBJ). From band structure plots, both ZnS and ZnTe reveals direct (Γv–ΓC) band gap semiconductors in nature with bandgap value equal to 3.5 and 2.3 eV while in Density Of States (DOS) major influence is observed due to p states of S/Te and d state of Zn. Prominent variation of optical responses such as high values of imaginary dielectric constants 𝜀1 (ω) and n (ω) refractive index suggests that ZnS and ZnTe are applicant materials for future photonics and microelectronic devices. The thermoelectric aspects were explored by Boltz Trap code to determine electrical and thermal conductivities, Seebeck coefficients, power factors and figure of merit. The figure of merits is closer to 1 while compared with p‐type ZnS and ZnTe, n‐type ZnS and ZnTe has good thermoelectric properties, which are attributed to low thermal conductivity of the hole and larger effective mass. The goal of this research is to investigate not only the detailed physical aspects but also to provide an overview of its future applications in optoelectronics, displays, sensors and microelectronic industry.

An innovative approach for the synthesis of 4Tris@Porphyrin and anderson polyoxometalate based covalent organic framework to reveal its potential for photocatalytic properties

Herein, a polyhydroxy containing metallo porphyrin linked through amide functional group with Anderson polyoxometalate (POM) was used to form TPMnA-COF. Structure and applications have been unlocked thoroughly by means of FT-IR, UV–visible, 1HNMR, PXRD, SEM and cyclic voltammetric (CV) spectral analysis. The TPMnA-COF was tested as catalyst to explore the photocurrent and photodegradation properties. ITO electrode was fabricated to study optical activity, absorption study and photocurrent generation. The adsorption study of TPMnA-COF has been studied using Langmuir and Freundlich model with calculated Langmuir constants qm, KL, RL and R2 values of about 12.42 mg/g, 0.33 M-1, 0.30 and 0.98 respectively. The 1/n, Kf and R2 values obtained from Freundlich adsorption isotherm were 0.70, 3.16 M-1 and 0.96 respectively. The band gap value evaluated via absorption edge of UV–visible spectra in DMSO solution was 2.75 eV while the band gap value calculated for ultra-thin film was 1.95 eV. The calculated real, imaginary dielectric constants, Urbach edge, refractive index and the electrical conductivity values for ultra-thin film of TPMnA-COF were 518.8, 2.9 × 10−11-8.1 × 10−11, −3.802 meV, 22.8–22.6 and 8.3 × 104−3.4 × 104 S/m), respectively. Responsivity for film was also tested using purple, blue, green, yellow, orange and red colourlights and the observed responsivity for different lower light intensities were 3.05, 2.9, 1.6, 1.55, 1.5 and 1.4 mA/W respectively. Furthermore, photodegradation activity of TPMnA-COF in Methylene-Blue (MB) and Rhodamine B(Rh–B) dyes under 3 W light. The results showed higher photocatalytic efficiency for Rh–B than that for MB with obtained degradation efficiency of 81 % and 60.4 %, respectively after 660 min. The scavengers such as ammonium oxalate (AO, h+), isopropanol (ISOP, •OH), catalase (CAT, H2O2) and superoxide dismutase (SODM, O2−●) were used to find out the effectiveness of each reactive specie to degrade the dyes solution in the mechanism of degradation. It was observed that AO (h+) and ISOP(•OH) were more active species in the photodegradation mechanism than CAT(H2O2) and SODM(O2−●).

“Extraction and studies of optoelectrical parameters in LaFeO3-polyvinyl alcohol composite films for optoelectronic application”

Ceramic LaFeO3 (LFO) nanoparticles were synthesized using the solid state reaction method. To grow and study the various optoelectrical parameters of polyvinyl alcohol (PVA) and LFO-PVA nanocomposite films (wt%), the solution casting technique were used. To study optical properties, these films were subjected to Ultraviolet–Visible spectroscopy. From the UV–visible spectra, the high reflectance and low transmittance nature of the sample was observed. The refractive index and extinction coefficient of these films were obtained from reflectance and transmittance data. The optical results reveal that increasing LFO doping concentration decreases the energy band gap (Eg) values from 5.20 to 2.74 eV, while Urbach energy (Eu) increases from 0.423 eV to 4.871 eV. With doping, the value of single oscillator energy (Eo) decreases from 6.212 eV to 3.658 eV, while dispersion energy (Ed) increases from 8.481 eV to 158.92 eV. With LFO doping concentration, optical constants and parameters such as refractive index, extinction coefficient, dielectric constants and electron energy loss function were determined from transmittance and reflectance data. The refractive index (n) and extinction coefficient (k) are calculated to be in the ranges from 1.4 to 12 and 5.85 × 10−5 ‒ 26 × 10−3, respectively. The real (ε1) and imaginary (ε2) dielectric constants vary from 2 to 138.8 and 3.01 × 10−4 ‒ 3.25 × 10−2, respectively. The volume and surface energy loss functions were determined to be 1.96 × 10−4 ‒ 1.03 × 10−6 and 1.34 × 10−4 ‒ 3.14 × 10−7, respectively. The optical density and skin depth (δ) shows variation with filler concentration (wt%). The maximum optical conductivity σ1(ω) and σ2(ω) for 48% (wt%) sample were found to be 1.5 × 105 and 1.08 × 109 S−1 at 220 nm. The wavelength dependent real and imaginary parts of the optical dielectric functions and the WDD model were used to calculate the fundamental parameters, including Nopt/m*, ε∞, τ, μopt, ωp, ωd, ρopt, and n0. The value of Nopt/m* was increased from 8.61 × 1052 m3Kg−1 to 5.60 × 1054 m3Kg−1. The reflection loss (RL) and average molar refraction (Rm) were found to increase with doping concentration. For these samples, the optical non linear susceptibility (χ(3)) was determined to be in the range from 3.77 × 10−15 to 2.94 × 10−7. The value of electronic polarizability αp decreases from 2.57 × 10−23 to 7.33 × 10−24 for PVA, while for the composite films the value of αp increases from 7.81 × 10−25 to 3.59 × 10−24 in the wavelength range 200–1000 nm. Also, these calculated parameters shows a decreasing trend with LFO doping contents. It was further observed that the investigated parameters exhibit a strong dependence on the LFO doping content. Based on these optoelectronic properties of this material, it could be used for possible optoelectronic applications.

Synthesis, Optical and D.C Electrical Characterization of (Pomegranate/PVA/TiO2) Ternary-Nanocomposites, As a Window to Improve Solar Cell Performance

This paper aims to fabricate a nanocomposite made of polyvinyl alcohol, titanium dioxide, and natural pomegranate dye that can function as a sunlight sensor for solar cells. The thin films' structural, optical and electrical properties of (Pomegranate/PVA-TiO2) were studied. Images from (FE-SEM) taken at a concentration of 0.3 weight percent revealed the structural features of the material., the surface of the (Pomegranate/PVA-TiO2) nanocomposite films demonstrations many aggregations or chucks arbitrarily dispersed of (TiO2) with grain size (47-55) nm. With an increase in natural dye content, transmittance decreases. Pomegranate dye had the most prominent peaks, measuring (76%) at a concentration of 1 ml. All optical constants, including parameters such n and k for transparency and extinction, r and i for real and imaginary dielectric constants, and electrical conductivity for optical conductivity, rise with pomegranate dye concentration. The results showed that the electrical conductivity at a concentration of (4 ml) recorded the greatest possible (6.4×10-6) (Ω.cm)-1, and the activation energy decreased with increasing concentration of pomegranate dye (0.29-0.20) eV. Then a solar cell was prepared from SnO2/Si, and the films were deposited on it, and the efficiency results were. After being coated with (Pomegranate/PVA-TiO2) nanocomposites, the efficiency (ƞ) increased from (4.3-4.75). In addition to the increase in current (Isc) from 23 to 30 mA/cm2. The final results showed that the (Pomegranate/PVA-TiO2) nanocomposite possesses a high transmittance, low activation energy and is sensitive to light in the Vis and IR regions, making it suitable for optical application.

Linear and nonlinear optical characterization of tellurium dioxide (α-TeO2) for generation of terahertz radiation using time-domain spectroscopy.

This paper reports the linear and nonlinear optical characterization of α-T e O 2 crystal in the optical and terahertz domains for efficient terahertz (THz) generation using a difference frequency mixing technique. We have ascertained the optical properties such as refractive index, absorption coefficients, real and imaginary dielectric constants, and coherence length l c=280m m at 1.77THz range using an indigenously developed THz spectrometer. The value of refractive index was ascertained from temporal and spectral THz profiles of the crystal and employed for calculating the Type I phase-matching angle, i.e.,θ=21.15∘ for the generation of tunable radiation between the 0.1 and 1.9THz range. The figure of merits in the optical and THz domains lie between the 0.02-0.015 range. The effective bandwidth of the crystal lies between the 0.1 and 3.0THz range.

The Influence of Nonlocal Metal-Dielectric Environments on Physical and Chemical Processes.

ConspectusPlasmonic nanolayers and laminar metallic/dielectric multilayers were originally developed for optical cloaking applications and lensing applications that could potentially image objects whose size was below the diffraction limit. These assemblies were initially formed from gold or silver nanorods grown within an alumina mesh. However, more recently, assemblies with similar properties have also been prepared by sequential thin-layer deposition of alternating layers of gold and magnesium fluoride (MgF2). These metal/dielectric composite materials enable control of the dielectric constant in the directions perpendicular to the layers and balance the real and imaginary dielectric constants of the assembly such that the speed and the amplitude of the waves traveling through the assembly are not attenuated.In this Account, we will also focus on a few of the applications ranging from surface wetting to fluorescence quenching to enhancement of photochemical reactions. First, we will share an introduction to processes used to create these materials, which are combinations of low refractive index metals and transparent higher index materials arranged in a scalable repeating fashion. Two fabrication methods were employed: an electrochemical deposition of Ag nanorods into an anodized alumina matrix which produced materials with an anisotropic negative refractive index material within the plane of the film and lamellar metal/dielectric layers in which the negative index perpendicular to the growth direction. These alternating layers of plasmonic metals and dielectric materials were ultimately chosen to prepare films for further testing, because of their relative ease of fabrication. We will continue with a discussion of a few of the applications of both of these nonlocal dielectric composite materials including more specialized plasmonic, composite, and hyperbolic metamaterials including fluorescence quenching, photochemical reactions, and surface wetting. In each of these applications, the unique response caused by the enhancement of the electric field and the interface between hyperbolic materials and plasmonic materials as they interact photophysically with their near neighbors is presented. In each of the applications, the enhanced electric field extends from the composite substrate layer to interact with its near neighbors and beyond. The presence of this extended interaction can be observed in the form of decreased emission lifetime, enhancement of photochemical reaction rates, and changes in the surface energies measured by contact angle goniometry. In this Account, all of these situations will be addressed. Finally, we will conclude with a summary and vision for the future as well as a discussion of the unique challenges and opportunities available as research active faculty at an HBCU.

Optical characteristics and bacterial-resistance ability of PVA/ZnO nanocomposites

Poly(vinyl alcohol) (PVA) thin films with different amounts of zinc oxide (ZnO) nanoparticles (NPs) (0.001, 0.002, 0.003, 0.004 and 0.005 ​g) were prepared using the casting method. The structural characteristics of the PVA polymer, ZnONPs and the mixture of polymer and ZnO NPs with a particle size of 80 ​nm have been studied using X-ray diffraction, Scanning Electron Microscopy and Fourier Transform Infrared spectroscopy. The optical characteristics of PVA/ZnO nanocomposites were studied in the wavelength range of 200–700 ​nm. According to experimental research, adding more ZnONPs to nanocomposites improves the PVA polymer's absorbance, absorption coefficient, extinction coefficient, refractive index and real and imaginary dielectric constants. As the amount of ZnONPs increases, the transmittance and energy gap of the PVA polymer decrease. Research on the antibacterial activity of these nanocomposites was conducted using Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella quasipneumoniae subsp. Similipneumoniae as pathogen microorganisms. According to the findings, the antibacterial activity of NPs is greatly influenced by their chemical make-up and form. Moreover, increasing the amount of ZnO in the composites causes an increase in antibacterial activity.

A simplistic approach for the synthesis of Covalent Organic Frameworks(COFs) comprising of tetrafunctionalized porphyrin and polyoxometalates to uncover catalytic applications

Tetrafunctionalized porphyrins are energetic synthons to prepare MOFs(Metal organic framework) and COFs(Covalent organic framework). Herein, a new tetrafucntionalized metallo porphyrin was used and connected via amide functionality with anderson polyoxometalates(POMs) and assembled two COFs(P@Ni-AndCOF & P@Cu-AndCOF). Structures, properties and their relationships have been unlocked thoroughly by means of FT-IR, UV–visible, 1HNMR, PXRD, SEM and cyclic voltammetric(CV) spectral analysis. The catalysts were tested to uncover the photocatalytic properties such as photocurrent and photodegradation properties. P@Cu-AndCOF and P@Ni-AndCOF were used to fabricate the ITO TiO2 coated electrodes to study optical activity, adsorption study and photocurrent generation. The adsorption study of P@Cu-AndCOF and P@Ni-AndCOF has been studied by using Langmuir and Freundlich model with calculated Langmuir constants qm, KL and RL values of about [7.44(mg/g), 8.02(mg/g)], [0.79(L/mg), 0.69(L/mg)] and (0.22 & 0.23) respectively. The correlation coefficient for adsorption obtained through Langmuir analysis were 0.92, and 0.95 for P@Ni-AndCOF and P@Cu-AndCOF respectively. The 1/n, Kf and R2 values obtained from Freundlich adsorption isotherm for P@Ni-AndCOF and P@Cu-AndCOF were (0.50 & 0.52), (3.325676 mg/g &3.328971 mg/g) and (0.94 & 0.93) respectively. The bandgap values evaluated via absorption edge of UV–visible spectra for P@Ni-AndCOF and P@Cu-AndCOF in DMSO solution were 2.82eV, and 2.83eV respectively while the bandgap values calculated for ultra-thin films were 1.78eV, and 1.85eV for P@Ni-AndCOF and P@Cu-AndCOF correspondingly. The calculated real, imaginary dielectric constants, Urbach edge, refractive index values and the electrical conductivity for ultra-thin film of P@Ni-AndCOF and P@Cu-AndCOF were (1.4x104-1.41x104& 2.19x10−9-2.45x10−9), (6.6x104-7.4x104&1.7x10−10-2.47x10−10), (0.323eV & 0.362eV), (32.9–32.4 & 33–30.4) and (5.8 × 104-2.9 × 104 &6.1 × 104-4.7 × 103 S/m) respectively. Furthermore, photodegradation activity of both catalysts was checked in Methylene-Blue(MB) and Rhodamine B(Rh-B) dyes under 3 W light. They showed higher photocatalytic efficiency for MB than that for Rh-B caused degradation efficiency of 89% and 79.3% for MB and 83% and 71.3% for Rh-B respectively after 660min. The photodegradation activity was also observed in dyes solutions along with some scavenger's ammonium oxalate (AO, h+-scavenger) and isopropanol (ISOP, •OH-scavenger) and it was observed that by the addition of these scavengers photodegradation rate was reduced.

PHEMA/PPy cytocompatible conductive cryogels: One-pot synthesis, characterization, and electrical properties

Conductive cryogels have gained significant research interest in recent years due to their potential biomedical applications such as implantable and wearable devices, biosensors, medical patches, health recording electrodes, drug delivery systems, bioactuators, etc. In this study, poly(2-hydroxyethy methacrylate)/polypyrrole (PHEMA/PPy) cryogel possessing macroporous morphology, conductivity, cytocompatibility, and mechanical compression properties were produced by cryopolymerization in the presence of excess ammonium persulfate. Electrical properties of the PHEMA and PHEMA/PPy cryogels as a function of frequency were compared using electrical impedance spectroscopy. At low frequencies, the real part of the dielectric constant of the PHEMA was found to be about 4-fold higher than that of the PHEMA/PPy whereas the average imaginary dielectric constant of PHEMA/PPy cryogels was observed to be nearly 6-fold higher than that of the PHEMA cryogels at the same frequency region. This behavior suggests that the addition of polypyrrole to the PHEMA cryogel increases the conductivity of the resultant material. This claim is further supported by comparing the results of the loss tangent, impedance and AC conductivity variations as a function of frequency for all samples. According to cytotoxicity, morphological, and AO/EB staining studies. PHEMA/PPy cryogel did not cause any toxic effect on L929 cells, except for PHEMA/PPy4 extract. These data suggested that the PHEMA/PPy cryogel with conductivity and cytocompatibility is a promising candidate in biotechnology and biomedical engineering.

Effect of annealing by CO2 laser on Structural and optical properties of zinc oxide thin films prepared by Sol – gel method

Laser heat treatment is one of the important industrial applications of laser and being studied at the present time as a substitute for conventional thermal annealing. In this research (ZnO) thin films have been deposition on a glass by (Sol - Gel / Spin Coating) technique and annealed by two ways, the first one using a convection oven, where they were annealing with three temperatures (400, 500, 600) °C for one hour, and the second way using a continuous (CO2) laser with (10.6 μm) wavelength and (10 W) power and three intervals (10, 15, 20) min, were studied structural and optical properties of membranes prepared by both ways to determine the effect of laser annealing on them, and the results of (XRD) tests showed that these membranes with the structural of multi-crystalline hexagon compact type and increase the degree of temperature oven annealing, as well as increasing the duration of the laser annealing lead to increased volumes of granular membranes rates. The results of the (AFM) tests to the topography of the surfaces of the membranes to be of crystalline uniformity and homogeneity superficially good, especially for laser annealed membranes. The results of optical examinations of these membranes also showed that they having high permeability, especially in the regions of the visible spectrum and the near-infrared and increased with increase the degree of oven annealing temperature and the duration of laser annealing, and less energy gap of these membranes values with increase the temperature degree of annealing or increase of laser annealing time, In addition the optical properties studied in this research included absorbance, reflectivity, refractive index, coefficients of absorption and extinction, and real and imaginary dielectric constants.

SYNTHESIS AND INVESTIGATION OF STRUCTURAL, SURFACE MORPHOLOGICAL AND OPTICAL PROPERTIES OF InSe/PMItz HYBRID HETEROJUNCTION

On a series of annealed and unannealed InSe thin films which were formerly produced by electrochemical deposition method, organic PMItz semiconductor compound was growth by physical vapour deposition (PVD) method. Structural analyses of the films carried out by X-ray diffractometry (XRD) method revealed that glass/ITO/InSe film formed in hexagonal InSe phase while glass/ITO/InSe(annealed) film formed in monoclinic In6Se7 and orthorombic In4Se3 phases. Surface analyses of the layers forming heterojunction were conducted by atomic force microscoby (AFM) and it is observed that the layers are homogenous and have different roughness values. Optical analyses of the films demonstrated that annealing of the film result with increased absorption coefficient and reduced energy band gap. Moreover, other optical parameters of the films i.e. refractive indice(n), extinction coefficient (k), real dielectric constant(Er), imaginary dielectric constant(Ei) and optical conductivity were determined and compared within 300-1000 nm range.

Influence of Molar Concentrations on Chemical Bath Deposited Cadmium Sulphide Thin Films

Thin films (TFs) of cadmium sulphide (CdS) have been deposited at 300K on soda-lime substrates. The effect of the molar concentrations was investigated using the X-ray diffraction (XRD) and UV-Vis Spectrophotometer. The XRD measurements show that the TFs were crystalline and increases with increasing molarities. The optical characteristics of the films were studied at spectra range of 300 – 950 nm. It indicated that the band gap energy ranged between 1.80 to 1.83 eV. The films exhibited a high transmittance in the visible and near infrared regions with a low reflectance values within same regions. Other optical constants like extinction coefficient (K), refractive index (n), real (Ɛᵣ) and imaginary (Ɛᵢ) dielectric constants and optical conductivity (σ) were determined with respect to photon energy (eV). These properties of CdS TFs confirm that the material could be beneficial in various optoelectronics applications.

Investigation of structural and optical properties of ternary polyaniline–polypyrrole–nickel oxide (PANI‐PPy‐NiO) nanocomposite for optoelectronic devices

AbstractA new ternary nanocomposite comprising nickel oxide (NiO) embedded into a binary polymeric network of polyaniline (PANI) and polypyrrole (PPy), i.e. PANI‐PPy‐NiO, is synthesized using an in situ chemical oxidative method. The infrared spectrum of PANI‐PPy‐NiO exhibits most of the characteristic peaks of unary nanoparticles with slight shift in the frequencies. The shift is due to the synergistic interaction of binary PANI‐PPy with the inorganic NiO nanoparticles. X‐ray diffraction pattern reveals the semicrystalline structure of the PANI‐PPy‐NiO nanocomposite with an average crystallite size of 22 nm. From Williamson–Hall plot, the micro‐strain value of as‐prepared PANI‐PPy‐NiO is found to be −0.16727. Surface morphology of PANI‐PPy‐NiO shows fine grains of NiO‐encapsulated PANI‐PPy that tend to coalesce and form an agglomeration assembly. The elements detected from energy‐dispersive X‐ray analysis indicate the purity of synthesis of the ternary material. Further, the optical constants obtained from UV–visible spectra (absorption coefficient, extinction coefficient, refractive index, optical conductivity and real and imaginary dielectric constants) are found to be higher for PANI‐PPy‐NiO than for the unary PANI, PPy and NiO nanoparticles. Tauc plot and Urbach energy studies indicate the low bandgap energy of PANI‐PPy‐NiO (2.67 eV) compared to unary nanoparticles. Further, the emission intensity peak (492 nm) observed in the photoluminescence spectrum of PANI‐PPy‐NiO corresponds to the blue region of the visible spectrum. Thus, the optical studies clearly indicate the high suitability of the synthesized PANI‐PPy‐NiO in visible‐light‐based device applications. © 2022 Society of Industrial Chemistry.