Direct Optical Band Gap Energy Research Articles

Elaboration, Structural and Optical Characterization of the New Ternary Chalcogenide SnSb<sub>2</sub>S<sub>5</sub>

In this study, -antimony sulfide (SnSb2S5) thin films with 200 nm, 312 nm, and 431 nm thicknesses were successfully fabricated using thermal evaporation. These films' structural, optical, and photoanode properties were meticulously characterized to assess their suitability for photovoltaic applications. X-ray diffraction (XRD) analysis confirmed the presence of an orthorhombic symmetry phase within the <em>Pnma</em> space group, ensuring the crystalline quality of the films. Raman spectroscopy further validated the crystal structure and provided detailed identification of the vibrational active modes specific to this pseudo-binary chalcogenide compound. Optical characterization revealed that the SnSb<sub>2</sub>S<sub>5</sub> thin films possess direct optical bandgap energies ranging from 1.91 to 1.99 eV, making them ideal for efficient light absorption in photovoltaic devices. The refractive index (n) displayed minimal variation within the absorption region, indicating stable optical properties. At the same time, it increased proportionally with film thickness outside the absorption region, suggesting enhanced optical behavior with thicker films. This characteristic is particularly advantageous for improving the efficiency of photoanode materials. The combination of favorable structural properties, optimal bandgap energies, and tunable optical responses positions SnSb<sub>2</sub>S<sub>5</sub> thin films as promising candidates for advanced photovoltaic and optoelectronic applications. These findings highlight the potential of SnSb<sub>2</sub>S<sub>5</sub> in developing high-performance photoanodes, contributing to the advancement of solar energy conversion technologies.

Diisopropylammonium hydrogen squarate: Synthesis and comprehensive analysis of non-linear optical co-crystal using X-ray, Hirshfeld, mechanical, optical and DFT methods

This research successfully synthesized a single co-crystal of diisopropylammonium hydrogen squarate using prolonged vaporization for crystal growth. Single-crystal X-ray spectrometry confirmed its monoclinic structure, and morphological predictions were made. UV–visible spectroscopy revealed its optical transmittance with a direct optical energy band gap of 3.45 eV. Photoluminescence studies showed a strong violet emission at 402 nm when excited by a 260 nm source. Microhardness study examined the crystal's mechanical attributes portraying the normal indentation size effect followed by a qualitative overview of half-penny crack dynamics. FTIR study aided in the discernment of varied vibrational modes with NH stretching being observed at 3078 cm−1. Thermal examination further revealed the crystal's stability up till 244 °C. Proton and carbon-13 NMR spectra were analyzed to verify the presence of functional groups and the overall molecular integrity. Intermolecular interactions were analyzed using Hirshfeld surface and fingerprint mapping. The Z-scan technique demonstrated the crystal's applicative potential in its third harmonic generation capability. Theoretical calculations with Density Functional Theory (DFT) supported the experimental findings, offering insights into optimized geometries, frontier molecular orbitals, natural population and bond orbital distributions, hyperpolarizability, molecular electrostatic potentials, IR vibrational modes, and UV absorbance profiles.

PVA/PEG/CuCo2O4/PANi/x wt% MWCNTs blended polymers: Improved the physical properties for energy storage devices and optoelectronic applications

The current investigation aims to enhance the optical and dielectric properties of poly (vinyl alcohol) (PVA)/polyethylene glycol (PEG) blended polymers via loading with copper cobaltite (CuCo2O4), polyaniline (PANi), and x wt% multi-walled carbon nanotubes (MWCNTs) for potential applications in optoelectronics and capacitive storage. The fabrication of PVA/PEG/CuCo2O4/PANi/x wt% MWCNTs blended polymers was carried out via casting and hydrothermal methods. Characterization of the blended polymer's structure and morphology was conducted using X-ray diffraction and scanning electron microscopy techniques. The impact of various fillers on the linear and nonlinear optical properties of the host blend was analyzed. The loaded blends demonstrated efficacy in blocking UVA, UVB, and UVC spectra, making them suitable absorbers for solar cells. The lowest values for direct and indirect optical band gap energy (Eg), of 5.34 eV and 4.44 eV were attained at x = 0.02. The blend with x = 0.01 displays the highest refractive index at λ = 600 nm. The optical conductivity exhibited nonmonotonically growth until peaking at x = 0.01. Analysis of chromaticity diagrams in CIE 1931 color space reveals that all blends emit blue-violet hues with slight variations in intensity. The fluorescence (FL) intensity of the doped blend is notably lower compared to the undoped counterparts. The doped blend (x = 0.03) showcases superior dielectric constants and ac conductivity values. The maximum energy density was achieved at 1 kHz for the host blend incorporating CuCo2O4/PANi. Overall, the observed characteristics indicate that PVA/PEG/CuCo2O4/PANi/x wt% MWCNTs blended polymers represent promising hybrid nanomaterials suitable for diverse applications.

An Insight into the Impact of Nano CuCo2O4 Doping on the Optical and Dielectric Performance of PMMA/Carbon Nanoparticles

In the present study, novel functional properties were achieved for polymethyl methacrylate (PMMA) through loading with carbon nanoparticles (CNPs) as well as varying quantities of CuCo2O4 nanoparticles. The blends obtained were subjected to different characterization techniques. Extensive investigations of different optical properties were carried out, covering linear and nonlinear optical properties. After the incorporation of CNPs/CuCo2O4 in the host polymer matrix, the absorbance, reflectance and refractive index exhibited improvements, while continuous reductions in both direct and indirect optical band gap energies were observed. Significant improvements in the linear and nonlinear optical parameters were observed with increasing CuCo2O4 doping levels. Dielectric measurements provided insights into the impact of CuCo2O4 content on the ac conductivity, energy density, dielectric properties, and electric modulus across all blends. The sample doped with 1.5 wt% exhibited the highest dielectric constant. In conclusion, the optical and dielectric properties of the PMMA/CNPs/x wt% CuCo2O4 blends make them promising candidates in optoelectronics and photocatalysis applications.

Fabrication and adapting the optical, and dielectric performance of PVC/ MnFe2O4/ZnMn2O4 nanocomposite films for optoelectronic applications

The current study focuses on the fabrication of hybrid flexible polymers composed of MnFe2O4/ZnMn2O4 nanocomposites doped polyvinyl chloride (PVC). The doped polymers show great potential for utilization in a wide range of optoelectronics applications. PVC/(1-x)MnFe2O4/xZnMn2O4 were made using the casting and sol gel processes. The effect of (1-x)MnFe2O4/xZnMn2O4 nanocomposite samples on the optical parameters of PVC polymer has been explored using ultraviolet–visible diffused reflectance measurements. Doped polymers might be useful as protective barriers against ultraviolet radiation of various wavelengths (UVA, UVB, UVC) and as excellent absorber materials for solar cells. The direct and indirect bandgaps (Eg) of PVC are 4.26 and 4.08 eV. The direct/indirect optical band gap lowered to their lowest 3.97/3.45 eV as the PVC doped with nanofillers contained 50 %/80 % ZnMn2O4, respectively. Different models were used to extracted the refractive index (n) of different polymers based on the obtained optical band gaps (direct/indirect). Doped polymers containing 50 and 80 % ZnMn2O4 had the highest n values using direct and indirect Eg values, respectively. The n value (obtained from the direct optical bandgap energy) of PVC increased from 2.209 to the maximum value (2.262) as x = 0.5. The n value (obtained from the indirect optical bandgap energy) of PVC increased from 2.349 to the maximum value (2.367) as x = 0.8. All linear and nonlinear optical parameters of PVC polymer were improved as it doped with the nanocomposite fillers. The fluorescence (FL) intensity of PVC was reduced as it was doped with (1-x)MnFe2O4/xZnMn2O4 and this intensity reduced as the content of ZnMn2O4. The standard (CIE) color space chromaticity diagram was used to analysis the FL spectra for different samples. The effect of nanocomposite samples on the AC conductivity, dielectric constants and electric modulus of the PVC was studied. At 1 kHz, the dielectric constant of PVC was increased from 11.745 to 12.906 and 12.096 for polymers with x = 0 and x = 0.2, respectively. The enhanced optical and dielectric properties of the PVC/(1-x)MnFe2O4/xZnMn2O4 polymers nanocomposites suggest that these materials are suitable for smart electronic devices.

Melt-quenched zinc sodium borate glasses: Understanding the role of ZnO/Na2O ratio in density, band gap, and radiation attenuation

In this work, we successfully prepared glasses with the composition 55 B2O3 – (45-x) ZnO – x Na2O (x = 0, 5, 10, 15) using the traditional melt quenching procedure. We analyzed the influence of substituting ZnO with Na2O at different concentrations on the attenuation of ionizing radiation and the glass density. Different analytical tools, such as XRD, FTIR, and UV-VIS spectroscopy, were used to investigate the crystal structure and optical features of the produced samples. The partial replacement of ZnO by Na2O significantly reduces the density (from 3.36 to 2.87 g/cm3) and, in contrast, increases the molar volume of the glass (from 22.32 to 25.06 cm3/mol). The positions of the main peaks in the FTIR spectra remain relatively unchanged with increasing Na₂O content. The Fermi energy (EF) of the glasses increases from 3.16 to 3.45 eV with increasing Na2O concentration. Samples with higher Na2O exhibit a blue shift in the UV cutoff. The direct and indirect optical band gap energy values (Ed/Ein) increase from 3.42 to 3.62 eV and 2.87–3.23 eV, respectively, with increasing Na2O concentration. The radiation attenuation performance of these glass samples was examined through evaluation of various parameters like linear and mass attenuation coefficients (LAC/MAC), effective atomic number (Zeff), and half-value layer (HVL) and tenth-value layer (TVL) in the photon energy range of 10 keV–15 MeV. LAC and MAC values decrease with decreasing ZnO content. The two buildup factors, energy (EBF), and energy absorption (EABF) have been recorded for the different compositions at penetration depths up to 40 mean free paths. Samples with the highest ZnO concentration show the lowest HVL and TVL values at the lowest photon energy (≤2 MeV). Increasing Na2O concentration significantly increases both EBF and EABF, with their maxima occurring at 5 MeV. Increasing zinc oxide in the glass improves its radiation shielding ability, suggesting potential applications for zinc alkali borate glasses in radiation protection.

Structural, Physical and Optical studies of Sc3+ doped Lithium Aluminum Borate glasses

Optically transparent lithium aluminum borate containing scandium glasses with composition 70B2O3 – 20Li2O – (10 – x) Al2O3 – xSc2O3 (where x= 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6 and 0.7 in mol %) were fabricated by conventional melt quenching technique. The non-crystalline nature of the samples was monitored by X-ray diffraction and it confirms non-crystalline nature. Structure of the fabricated glasses are assessed using the Fourier transform infrared spectra. The absorption spectra of these glasses have been recorded in the wavelength range 200 nm – 1100 nm. Direct and indirect optical energy band gaps were calculated from Tauc’s plots. The physical parameters such as refractive index (RI), optical basicity and interaction parameters were determined using proper formulas to know the characteristics of fabricated glass matrix. The results obtained indicate that 0.3 mol% Sc2O3-containing BLASc glass is more suitable for w-LEDs and lasers applications.

Optical and Dielectric Characteristics of Poly (Methyl Methacrylate)/Polyethylene Oxide/Carbon Nanoparticle Composites Loaded with Nano NiFe2O4

The current study proposes a simple, low-cost, and functional method of doping a pure matrix of poly (methyl methacrylate)/polyethylene oxide/carbon nanoparticles (PMMA/PEO/CNPs) with nano nickel ferrite (NiFe2O4) as a filler. To create NiFe2O4 nanoparticles, a straightforward chemical growth, sol-gel auto-combustion system was used. Next, environmentally friendly and cost-effective, undoped and blended polymers doped with NiFe2O4 using a solution-casting method were synthesized. Rietveld refinement analysis was used to investigate the structure and microstructure of the NiFe2O4. Transmittance electron microscopy was used to confirm the nano nature of the filler. X-ray diffraction was used to verify the crystallite nature of the undoped and doped PMMA/PEO/CNPs blends with NiFe2O4. The linear optical characteristics of the proposed blends were obtained using a diffuse reflectance spectrophotometer. The measured optical parameters included transmittance, absorbance, reflectance, direct and indirect optical bandgaps, absorption coefficient, linear refractive index, extinction coefficient, dielectric constant, energy loss functions, in addition to optical and electrical conductivities. Also, nonlinear optical constants for the synthesized blends, such as the linear and third nonlinear susceptibilities, nonlinear refraction coefficient and nonlinear absorption coefficient, were calculated. The direct and indirect optical band gap energies of the PMMA/PEO/CNPs blends were 4.97 and 4.8 eV, respectively. As the NiFe2O4 doping level increased in the blend to 2.5 wt%, the optical band gap energy values decreased to 4.54 and 4.64 eV, respectively. The fluorescence spectra of the undoped and doped PMMA/PEO/CNPs blended polymers with nano NiFe2O4 were also explored. The effect of NiFe2O4 doping amount on the energy density, electric dielectric constant, ac conductivity and electric moduli of the host blend was also studied. In conclusion, the considered NiFe2O4-doped PMMA/PEO/CNPs blends have an effective and promising role in optoelectronic applications.

Optical properties and luminescence behavior of Tb3+-Doped SiO2–Al2O3–BaO–BaF2 oxyfluoride glasses and glass ceramics

In this study, oxyfluoride glasses with chemical composition of 45SiO2–15Al2O3–10BaO–30BaF2-xTbF3 (x = 0.2, 0.4 and 0.6 (mole ratios)) were prepared through the conventional melt-quenching method. Raman and FTIR spectra as well as molar volume calculations proved the creation of more non-bridging oxygens (NBOs) in presence of more TbF3 content. Accordingly, absorption edge in UV–Vis spectra showed a slight red-shift to longer wavelengths. The glass with 0.4 mol ratios of TbF3, exhibited the highest photoluminescence emission and its green-to-blue intensity ratio was 0.66. Therefore, this sample was chosen and heat treated at 630, 650 and 675 °C to prepare glass ceramic samples. For the sample heat treated at 650 °C, photoluminescence intensity increased and green-to-blue intensity ratio reached 0.69. Also, lifetimes of green and blue emissions increased from 3.35 ms to 3.67 ms and from 2.95 ms to 3.10 ms, respectively, when the base glass heat treated at 650 °C. Formation of BaF2 nanocrystals in glass ceramics moved the UV–Vis absorption edge to longer wavelengths significantly. Increment of the weak and dangling bonds in crystallized samples reduced Fermi energy, indirect and direct optical band gap energies from 3.792 eV to 3.301 eV, from 3.522 eV to 3.093 eV and from 4.095 eV to 3.582 eV respectively, which led to higher semiconducting behaviors.

Influence of Al Doping on the Structural, Optical, and Electrical Characteristics of ZnMn2O4

Doped zinc manganite samples were synthesized using the sol-gel method, incorporating varying amounts of aluminum (ZnMn2-xAlxO4, x = 0, 0.03, 0.05, 0.07, 0.1). High quality X-ray diffraction data enabled detection and accurate quantification of the predominant phase ZnMn2O4 (ZMO) and minor phase ZnO. The structure and microstructure of developed phases were investigated applying the Rietveld refinement method. The nanoscale nature of the samples was examined by High-resolution transmission electron microscopy (HRTEM); the incorporation of Al into the ZMO matrix and the oxidation states of various cations were studied through X-ray photoelectron spectroscopy (XPS). The introduction of Al has resulted in a modification of the light-absorption characteristics of the ZMO sample. Specifically, the direct optical band gap energy of ZMO decreased from 2.45 to 2.25 eV with an increase in the amount of Al doping to 0.1. Moreover, an investigation was conducted into the impact of Al doping amount, frequency, and temperature on the dielectric constant, dielectric tangent loss, ac conductivity, complex impedance, and complex electric modulus. It was observed that all samples, except for the sample with x = 0.05, exhibited ferroelectric features. The activation energies for the samples with x = 0, 0.03, 0.05, 0.07, and 0.1 were determined to be 0.274, 0.456, 0.099, 0.103, and 0.152 eV, respectively. The conduction mechanism type in the different samples was identified. The obtained changes of dielectric properties indicated the capability of improving the ZMO characteristics for various applications via controlling the doping content of Al.

Response of the modified GAFCHROMIC EBT2 radiochromic film to DC glow discharge plasma

The response of the modified GAFCHROMIC EBT2 radiochromic film to DC Oxygen glow discharge plasma was investigated using a flatbed scanner and an UV–Vis spectrophotometer. The film was modified by removing the polyester overlaminate, adhesive, and topcoat layers with a total thickness of 80 µm, and is now referred to as EBT2-M. The EBT2-M films were exposed to DC Oxygen plasma for different durations: 0, 0.5, 1, 2, 3, 4, 7, and 10 min. The exposed films exhibit coloration homogeneity with an average variation of (1.6 ± 0.3) × 10−4 pixel values/µm, irrespective of the applied exposure time. The pixel values of the red-and-green channels and weighted grayscale images decreased exponentially with different sensitivity amounts to ∼\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\sim$$\\end{document} 39.67, 49.69, and 42.11 min−1, respectively, as the exposure time increased. The two absorption peaks at 580 ± 4 nm and 632 ± 4 nm in the UV–Vis absorption spectra of the exposed GAFCHROMIC EBT2-M radiochromic films are increasing with increasing exposure time up to 4 min, thereafter saturated for prolonged exposure time. The integrated absorbance in the range from 400 to 700 nm is linearly correlated with the exposure time. The indirect and direct optical energy band gaps and Urbach energy of the modified GAFCHROMIC EBT2 film are weakly correlated with the exposure time. These findings suggest the utilization of the modified GAFCHROMIC EBT2 radiochromic film as a novel and simple technique for plasma diagnostics.

Optical, Dielectric, and Electromagnetic Microwave Absorption Properties of Hexagonal Ba3(VO4)2

In this work, we used a simple sol-gel synthesis technique to prepare hexagonal Ba3(VO4)2. X-ray diffraction (XRD), Fourier transform infrared (FTIR), and Raman spectroscopy were performed, confirming that Ba3(VO4)2 has a hexagonal structure. To investigate the influence of interfacial interactions at grain boundaries on microwave absorption, AFM studies were performed. UV–vis studies show the direct and indirect optical energy band gaps of Ba3(VO4)2 were determined as 3.81 eV and 3.25 eV, respectively. The dielectric studies reveal that the dielectric constant (ε׳) of Ba3(VO4)2 ranges from 1.55 to 6.02 in the frequency range of 2–20 GHz, with an average ε׳ value of 3.84. The microwave absorption properties of Ba3(VO4)2 were evaluated in the frequency range of 8–18 GHz, covering the X and Ku bands at different thicknesses from 4.5 mm to 8 mm. The highest effective absorption bandwidth (EAB) of 4.44 GHz was observed within the frequency range of 12.83–17.27 GHz, with a maximum reflection loss of −71.43 dB at a resonance frequency of 15.05 GHz. Additionally, at a thickness of 7.5 mm, Ba3(VO4)2 achieved a maximum reflection loss of −75.22 dB at 10.03 GHz, with an EAB of 2.94 GHz (covering the X band from 8.57 GHz to 11.51 GHz).

LDPE/Bi2O3 nanocomposites: Enhanced mechanical, dielectric, and optical properties

AbstractThis study is focused on investigating the role of bismuth oxide (Bi2O3) nanoparticles to improve structural, optical, electrical, and mechanical properties of low‐density polyethylene (LDPE). For this purpose, Bi2O3 nanoparticles were synthesized by using the solvothermal method and examined by transmission electron microscopes (TEM), x‐ray diffraction (XRD), Fourier transformed infrared (FTIR) spectroscopy, and ultraviolet–visible (UV–Vis) light absorption methods. LDPE‐based nanocomposites were prepared by changing the nanoparticle additive ratio in the composite from 0% to 2% by weight. The composites were analyzed in the context of their FTIR spectra, atomic force microscope (AFM) images, UV–Vis light absorption spectra, stress–strain curves, and energy storage abilities. While the AFM findings indicate a smoother surface for the composites, the optical band gap analysis reveals a slightly decreased direct optical band gap energy. The analyses based on dielectric spectroscopy also highlight the LDPE/0.5% n‐Bi2O3 composite in terms of the best energy storage capability. Additionally, the highest Young's modulus, toughness, stress at break, and percentage of strain at break were also recorded for the LDPE/0.5% n‐Bi2O3 composite. In this context, the LDPE/0.5% n‐Bi2O3 composite with improved dielectric and mechanical properties can be suggested as a new promising LDPE‐based nanocomposite with better properties for industrial purposes.

P2O5–TiO2–CaO glasses as a host for Nd3+, structure and optical properties

The system of P2O5–TiO2–CaO was investigated as a proper host for rare-earth ions. Glasses comprising P2O5, TiO2, and CaO were doped with neodymium (0.5, 1, and 1.5 mol%) through melting method at 1350–1400 °C. UV–Vis spectrum showed a rise in the absorbance by increasing the dopant content. The absorbance at the wavelength of 583 nm was 2.4 times higher than the glass containing 0.5 mol% Nd2O3 (G-Nd 0.5). Optical findings also indicated a decline in the emission intensity at all wavelengths. FT-IR and Raman analysis revealed that Nd entered the structure of the phosphate glass as a modifier. The direct Optical band gap energy showed a decline from 3.38 eV in G-Nd0 to 3.33 eV for G-Nd1.5. Nd3+ incorporation led to an increase in the Urbach energy as the highest and lowest Urbach energies were recorded in G-Nd1 (0.017 eV) and G-Nd0 (0.058).

Enhancement of Ni–Zn ferrite nanoparticles parameters via cerium element for optoelectronic and energy applications

This work is concerned with fabricating ferrite nanoparticles of nickel–zinc with the chemical formula: Ni0.55Zn0.45Fe2−xCexO4, 0 ≤ x ≤ 0.011 by co-deposition technique and modifying their electrical, microscopic, spectroscopic, optical, electrical and dielectric properties as advanced engineering materials through doping with the cerium (Ce) element. XRD patterns displayed that the samples have a monophasic Cerium–Nickel–zinc (CNZ) spinel structure without other impurities for cerium concentration (x) ≤ 0.066. Both values of crystallite size and lattice parameters decrease from 33.643 to 23.137 nm and from 8.385 to 8.353 nm, respectively, with the increasing Ce ions substitution content from 0 to 0.066. SEM images indicate that grains of the fabricated compounds are smaller, more perfect, more homogeneous, and less agglomeration than those of the un-doped Ni–Zn nano-ferrites. The maximum intensity of first-order Raman spectral peaks (Eg, F2g(2), A1g(2), and A1g(1)) of CNZ ferrite nanoparticles are observed at about (330, 475, 650, 695) cm−1, respectively, that confirms the CNZ samples have the cubic spinel structure. The direct and indirect optical energy bandgaps of CNZ samples have a wide spectrum of values from semiconductors to insulators according to cerium concentration. The results showed that the values of dielectric constant, dielectric loss factor, and Ac conductivity and the conductivity transition temperature are sensitive to cerium ions content. AC conductivity exhibited by the CNZ samples has the semiconductor materials behavior, where the AC conductivity increases due to temperature or doping concentration. The results indicate that Ni0.55Zn0.45Fe1.944Ce0.066O4 ferrite nanoparticles may be selected for optoelectronic devices, high-frequency circuits, and energy storage applications.

Exploring the Structural, Optical and Dielectric Behaviors of Poly(Methyl Methacrylate)/Multiwalled Carbon Nanotubes/MnFe2O4-ZnMn2O4 Nanocomposite Polymers

Polymethyl methacrylate/multiwalled carbon nanotubes (PMMA/MWCNTs)/3 wt % (1-x) MnFe2O4/xZnMn2O4 (x = 0, 0.2, 0.5, 0.8) samples were formed using the sol-gel and solvent casting routes. The Rietveld refinement method was applied to explore the different phases in the MnFe2O4/xZnMn2O4 samples. The nano natures of the fillers were investigated using a high resolution transmission electron microscope. The X-ray diffraction technique was used to study the nature of the structure of all polymers. The direct and indirect optical band gap energy (E g) values for our PMMA/MWCNTs were 5.01 and 4.71 eV, respectively. The direct and indirect E g values were reduced by doping the polymer with (1-x)MnFe2O4/xZnMn2O4; they were 4.95 and 4.56 eV, respectively, for polymer doped with x = 0.8. The effect of the amount of ZnMn2O4 phase in the nanofillers on the linear and nonlinear optical parameters and also the dielectric constants, electric modulus, and energy density of PMMA/MWCNTs were studied using diffused reflectance and LCR meter techniques. Under an excitation wavelength of 317 nm, the fluorescence spectra of pure PMMA/MWCNTs as well as PMMA/MWCNTs loaded with (1-x)MnFe2O4/xZnMn2O4 samples were inspected.

Influence of Polyaniline on the Structural, Linear/Nonlinear Optical, and Dielectric Characteristics of Poly(Vinyl Chloride/Poly (Ethylene Oxide) Blends

Polyvinyl chloride (PVC)/polyethylene oxide (PEO)/x wt % polyaniline (PANI) polymer blends were produced using a solvent casting method. X-ray diffraction was used to investigate the formed blends. The effect of adding different amounts of PANI on the light absorbance, transmittance, reflectance, extinction coefficient, refractive index, optical dielectric properties, nonlinear optical parameters and relaxation time characteristics of the PVC/PEO blends were explored. The direct and indirect optical band gap energies of the undoped PVC/PEO were 4.25 and (4.06, 2.76) eV, respectively. The direct and indirect optical band gap energies were reduced to their lowest values (4.02, 3.1) and (3.68, 2.14, 1.12) eV as the amounts of PANI were increased to 0.2 wt %. The effect of alloying between PVC and PEO and adding PANI on the emitted fluorescence spectra under various excitation wavelengths were investigated. All samples displayed varying degrees of blue-violet, blue, or blue-green colors depending on the concentrations of PANI.

Investigating the impact of calcination temperature on the structural and optical properties of chromium-substituted Mg–Co ferrite nanoparticles

The primary objective of this study is to comprehensively examine how the calcination temperature affects the structural, infrared, and optical properties of Mg0.6Co0.4FeCrO4 compounds. These compounds were synthesized using the sol-gel method and subjected to calcination at two distinct temperatures, namely 900 °C and 1100 °C. The X-ray diffraction measurements confirmed that the compounds adopt a cubic crystal structure with a space group of Fd3¯m. Furthermore, the FTIR analysis of these compounds revealed the presence of an absorption band corresponding to the stretching vibration of the oxygen atom and metal ions within the tetrahedral site. As the calcination temperature increased, various properties showed notable changes. The crystallite size, determined using the Debye-Scherrer equation from the strongest diffraction peak, increased from 48 nm at 900 °C to 56 nm at 1100 °C for the compounds. Additionally, the direct optical band gap energy (Eg) decreased from 1.346 eV to 1.322 eV with the rise in calcination temperature from 900 °C to 1100 °C. Furthermore, the Urbach energy values decreased from 0.491 eV to 0.310 eV as the calcination temperature increased from 900 °C to 1100 °C. The compounds exhibited direct optical transitions as per the absorption coefficient (α) and Tauc's model. The study delved into the impact of calcination temperature on various optical properties. Specifically, the penetration depth, extinction coefficient, and refractive index were thoroughly investigated and their findings interpreted. In addition, the dispersion parameters were examined using the Wemple and DiDomenico single oscillator model and it was discovered that these parameters were significantly influenced by the calcination temperature. Moreover, as the calcination temperature increased, the optical dispersion moments (M−1 and M−3) exhibited a decrease. Finally, the study also explored and interpreted the influence of calcination temperature on the real and imaginary parts of the dielectric permittivity and conductivity of the compounds. These analyses provide valuable insights into how calcination temperature affects the optical characteristics of the studied compounds.

Novel cobalt lead ferrite (CPFO)/Ps nanocomposites with enhanced structure, optical and dielectric properties

Hexa-spinel ferrite nanoparticles of Cobalt Lead Ferrite (CPFO) were prepared by a flash auto combustion method, while xCPFO/PS (x = 0, 2.5, 5, and 7.5 wt%) nanocomposite films were synthesized by casting method. The diffraction pattern and Rietveld refinement of CPFO nanoparticles proved that they have a face-centred cubic spinel and a hexagonal structure. HRTEM micrographs of cobalt lead ferrite (CPFO) nanoparticles show an average particle size of around 30 nm. FESEM cross-section images of CPFO/PS nanocomposite films showed CPFO nanoparticles dispersed in the PS matrix. All optical characteristics of the synthesized nanocomposite films, including absorbance, transmittance, direct and indirect energy band gap, Urbach energy, excitation coefficient, and refractive index, were investigated using a UV-visible spectrophotometer examination. The direct optical energy band gap lowered from 4.533 eV to 4.368 eV, and the indirect energy optical bandgap lowered from 4.337 eV to 4.146 eV, while the Urbach energy increased from 0.103 eV to 0.209 eV with increasing the nanofillers from 0 to 7.5 wt%. Broadband dielectric spectroscopy was used over a wide frequency range (0.1 Hz–1 MHz). The dielectric real permittivity (ε′), the dissipation factor tan (δ) and the electric modulus (M′&M′′) measurements were studied. CPFO nanoparticles’ addition significantly enhanced the dielectric real permittivity (ε′), the dissipation factor tan (δ), and the ac conductivity of all nanocomposites.

Photodetection Properties of CdS/Si Heterojunction Prepared by Pulsed Laser Ablation in DMSO Solution for Optoelectronic Application.

The high-quality n-type CdS on a p-type Si (111) photodetector device was prepared for the first time by a one-pot method based on an ns laser ablation method in a liquid medium. Cadmium target was ablated in DMSO solution, containing sulfur precursor, and stirred, assisting in 1D-growth, to create the sulfide structure as CdS nano-ropes form, followed by depositing on the Si-substrate by spin coating. The morphological, structural, and optical characteristics of the CdS structure were examined using X-ray diffraction, transmission, and scanning electron microscopy, photoluminescence, and UV-VIS spectroscopy. From X-ray diffraction analysis, the growing CdS spheres have a good crystal nature, with a high purity and desired c-axis orientation along the (002) plane, and the crystallinity was around 30 nm. According to optical characterization, high transparency was found in the visible-near-infrared areas of the electromagnetic spectrum, and the CdS spheres have a direct optical energy band gap of 3.2 eV. After that, the CdS/Si hetero-structured device was found to be improved remarkably after adding CdS. It showed that the forward current is constantly linear, while the dark current is around 4.5 µA. Up to a bias voltage of 4 V, there was no breakdown, and the reverse current of the heterojunctions somewhat increased with reverse bias voltage, while the photocurrent reached up to 580 and 690 µA for using 15 and 30 W/cm2 light power, respectively. Additionally, the ideal factors for CdS/Si heterojunction were 3.1 and 3.3 for 15 and 30 W/cm2 light power, respectively. These results exhibited high performance compared to the same heterojunction produced by other techniques. In addition, this opens the route for obtaining more enhancements of these values based on the changing use of sulfide structures in the heterojunction formation.