In this study, polymeric graphitic carbon nitride (g-C3N4) semiconductors was synthesized via a thermal condensation method. Subsequently, Ag/AgBr nanoparticles with varying ratios were decorated onto the g-C3N4 surface using the water/oil emulsion method. The resulting nanocomposites were characterized using XRD for phase identification and structural analysis, HR-TEM and SEM&EDAX for morphological structure, particle size, and elemental composition analysis, and XPS for investigating the chemical state and electronic structure. The impact of Ag/AgBr content on the optical properties of g-C3N4 were also studied such as (optical bandgap (Eg), refractive index (n), extinction coefficient (k), optical conductivity (σopt) and dielectric function (ε*)), Electrochemical impedance spectroscopy (EIS), PL spectroscopy and Chrono-amperometric investigations were conducted to assess the charge transfer capabilities and long-term durability of the prepared nanocomposites. The results revealed a reduction in Ag/AgBr particle size with an increase in g-C3N4 content, accompanied by a decrease in the optical bandgap from 2.444 eV to 2.393 eV. Furthermore, the nanocomposites exhibited enhanced degradation efficiencies of RhB dye, with the highest tested content of Ag/AgBr achieving 100% degradation after 120 min of irradiation. However, the challenge of catalyst separation after the degradation process remained. To address this issue, we developed a novel approach by impregnating Ag/AgBr@g-C3N4 photocatalyst onto a floating porous sponge using a simple sugar-template technique, offering potential as a reusable photocatalyst material. Furthermore, the 3D PDMS − Ag/AgBr@g-C3N4 photocatalyst was evaluated and found to maintain nearly the same photocatalytic efficiency for up to 5 consecutive cycles.

TiO 2 nanoparticles (NPs) were prepared by the sol -gel method and then encapsulated with different thicknesses of SiO 2 as a shell using the Sto ber method. The crystal, chemical structure, and morphology of the core-shell TiO 2 @SiO 2 NPs were characterized using XRD, FTIR, and TEM techniques. The amorphous nature of the shell (SiO 2 ) was shown by XRD examination, which influenced the crystallinity of the TiO 2 NPs, while FTIR data verified the association between SiO 2 and TiO 2 , and a TEM study validated the coating of TiO 2 NPs with SiO 2 . The optical absorption of TiO 2 NPs was characterized by a sharp absorption edge around 343 nm, which redshifted to a higher wavelength region with increasing shell thickness. The direct bandgap decreased as the shell thickness of TiO 2 @SiO 2 increased. The measurements revealed a clear trend, with the bandgap values falling from 3.97 eV for TiO 2 to 3.60, 3.37, and 3.26 eV for shell thicknesses of approximately 2.5, 5.5, and 8 nm, respectively. Significant improvement in the optical conductivity of TiO 2 NPs was observed with an increase in shell thickness, accompanied by an increase in refractive index and extinction coefficient. This enhancement could potentially lead to breakthroughs in the field of nanotechnology. The Wemple-DiDomenico model was applied to compute the nonlinear refractive index (n 2 ), first- and third-order ( chi (1) & chi (3) ) susceptibilities values. The addition of a SiO 2 shell to the TiO 2 core resulted in a remarkable improvement in all nonlinear optical parameters. The ( chi (3) ) value was increased from 2.08 x 10 -14 for pure TiO 2 NPs to 3.04 x 10 -09 for the core-shell TiO 2 @SiO 2 sample with a shell thickness of 8 nm.

Solution-casting was used to create films of polyvinyl alcohol (PVA) nanocomposite containing different concentrations of Fe3O4@SiO2 nanoparticles (NPs). The co-precipitation technique was used to synthesize Fe3O4@SiO2 NPs. Fe3O4@SiO2 impact on the PVA structure was investigated via X-ray diffraction (XRD), optical microscope, and Fourier transform-infrared (FT-IR) techniques. XRD reveals the destruction of the PVA semi-crystallinity with the Fe3O4@SiO2 additive. FT-IR analysis supported hydrogen bond formation between PVA molecules and the Fe3O4@SiO2 surface. The UV–visible spectrophotometer was used to investigate the optical parameters. The optical bandgap decreased with increasing the Fe3O4@SiO2 concentration in the PVA matrix. Based on the optical bandgap, the theoretical linear refractive index (n) was deduced with theoretical models. The enhancement in the nonlinear refractive index and nonlinear optical susceptibility with the Fe3O4@SiO2 additive to the PVA matrix makes it a possible material for nonlinear optical devices.

This study explores the enhancement of polyvinyl alcohol (PVA) films by incorporating erbium oxide (Er2O3) nanoparticles using the casting solution method. We investigated the structural, optical, electrical, dielectric, and mechanical properties of PVA-Er2O3 nanocomposite films with varying Er2O3 concentrations (2.5, 5, 7.5, and 10 wt%). Structural analyses confirmed successful nanoparticle integration. Optical measurements revealed reduced transparency and bandgap, alongside increased refractive index. Electrical conductivity showed significant improvement with Er2O3 inclusion. Dielectric properties demonstrated enhanced performance, with frequency dependent studies and Argand plot analysis providing insights into charge transport and relaxation mechanisms. Mechanical testing indicated increased tensile strength and Young's modulus, with the 10 wt% nanocomposite showing comparable performance to pure PVA. These findings highlight the potential of PVA-Er2O3 films for advanced applications in electronics, sensors, and energy storage systems.

The co-precipitation method was used to synthesize ZnO nanoparticles (NPs). Then, graphene oxide (GO) sheets which were reduced during the reaction process to become (rGO), were embellished with ZnO NPs. The impact of rGO on the structure and morphology of ZnO was investigated using XRD, FTIR, TEM, and SEM techniques. Investigating the optical characteristics was done using UV-vis spectroscopy. ZnO exhibits a hexagonal phase, as proved by XRD. The average crystallite size reduced from 22 to 18 nm after being anchored on rGO sheets. TEM and SEM testify to the presence of ZnO in nanoscales with quasi-spherical shapes, which dispersed homogeneously along the GO sheets. The optical bandgap was increased from 2.57 eV to 3.17 eV for ZnO and ZnO-rGO, respectively. Based on the obtained optical bandgap, the refractive index of ZnO and ZnO-rGO nanocomposite was theoretically determined using different models such as Moss and Ravindra models. ZnO-rGO nanocomposite's ability to change optical characteristics makes it a superior nominee for optoelectronic applications.

Fe3O4@SiO2 (FS) nanocomposite was synthesized through the co-precipitation method and utilized as a filler material in the polyvinyl alcohol (PVA) matrix to obtain PVA/ iron oxide@silica Fe3O4@SiO2 (PFS) films. This study presents the synthesis and characterization of flexible polymer nanocomposites comprising polyvinyl alcohol (PVA) matrices embedded with iron oxide @ silica. Through the analysis of the composite, we observed a significant enhancement in the thermal stability of the nanocomposites with increasing Fe3O4@SiO2 content. X-ray photoelectron spectroscopy (XPS) spectra have been used to provide more information about the chemical state and electronic structure of the polymer film. Dielectric spectroscopy revealed notable improvements in electrical properties, including increased real electric modulus and permittivity. Mechanical investigation showed an improvement in the tensile strength, meanwhile, Young's modulus has improved from 341.2 to 1789.8 MPa, indicating that (PVA) and FS successfully complexed and interacted strongly. These findings underscore the potential of these nanocomposites for high-performance applications in energy storage devices and other fields requiring robust dielectric materials.

Herein, the polyvinyl alcohol (PVA) films doped with various concentrations of Bi2O3-NiO-rGO (BNG) nanoparticles were prepared through casting method. BNG nanoparticles were synthesized first using the co-precipitation method and then loaded into the polymer matrix. Various techniques like X-ray diffraction, Raman spectroscopy, and optical microscopes were used to determine the PVA's structure after BNG nanoparticle additives. The thermal stability of the PVA's film after the additive BNG nanoparticles was examined using the DSC technique. Furthermore, the optical parameters including bandgap energy (E-g), Urbach energy (E-U), refractive index (n), optical conductivity, and optical dielectric constants were investigated via the absorbance and transmission data recorded using UV-visible spectroscopy. In addition, the photoemission spectra of the PVA matrix were determined after the inclusion of BNG nanoparticles. The Eg value decreases from 5.57 eV to 3.94 eV and from 4.8 eV to about 1.98 eV for direct and indirect transitions, respectively. While the EU value increases from 0.39 eV for pure PVA to about 3.23 eV for PVA: 4%BNG. The refractive index grows with the insertion of BNG to the PVA from 1.387 for pure PVA to about 5.157 for PVA: 4%BNG, which is a good suggestion for optical glasses applications. In addition, the increase in optical dielectric constants and optical conductivity with rising the BNG nanoparticle concentrations in the PVA matrix was confirmed. Such enhancement suggests the use of prepared samples in optical device applications.

Mn2O3 and Mn2O3/reduced graphene oxide (rGO) composites were prepared by the hydrothermal and sonochemical method, respectively. The prepared samples were characterized via X-ray diffraction, Transmission electron microscope, Fourier transform infra-red, and Raman spectroscopy. Di-Manganese tri oxide morphology appeared new morphology as Polyhedron Prism Nano-rods as to the best of our knowledge, no work has described before for Mn2O3 Nanoparticles (NPs). The optical properties were measured by UV-visible spectrometer. The obtained data from the absorption spectra was used to investigate the optical parameters. The optical band gap was tuned to lower value and the refractive index increased. The obtained results revealed that the optical and morphological structure of Mn2O3 were enhanced via the addition of rGO sheets to the matrix which make it useful in optoelectronic applications.

Magnetic iron oxide (Fe3O4) and Fe3O4 @SiO2 core-shell were prepared via co-precipitation and modified Stober methods. Structural, morphological, and optical properties were examined using XRD, FTIR, and UV-visible spectrophotometer. This study used three different methods to deduce the studied nano -particles' optical gap energy: (i) the Tauc model, (ii) the absorption spectrum fitting model, and (iii) the derivation of the absorption spectrum fitting model. The calculated values of gap energy of Fe3O4 @SiO2 NPs by the three different methods are higher than the corresponding values of Fe3O4 NPs and SiO2 NPs. The optical oscillator strength (f) of Fe3O4 @ SiO2 NPs has the greatest value (24.4 eV2) compared to the others. The values of the high-frequency dielectric constant (epsilon infinity) are greater than the square of the infinite wave-length refractive index (n2). Therefore, the free charge-carrier contribution during the incidence of photon energy on the tested NPs significantly affects the polarization. The high value of the third-order nonlinear optical susceptibility (chi(3)) of Fe3O4 @ SiO2 NPs can candidate them to be applied in the applications of nonlinear optics as power limiters. The nonlinear absorption coefficient (beta c) increased by increasing the incident energy and has a maximum value in a range of energies from 3.25 eV to 5 eV, for all the samples. The synthesized Fe3O4 @SiO2 core-shell nanomaterials with enhanced optical parameters is considered as a suitable candidate in nonlinear optical applications.(c) 2023 Elsevier B.V. All rights reserved.

Polyvinyl alcohol (PVA) films doped with Fe 2 O 3 -reduced graphene oxide (rGO) nanoparticles (NPs) were prepared using a casting-method. Fe 2 O 3 NPs were synthesized via the hydrothermal process, and then Fe 2 O 3 NPs were decorated on the graphene oxide (GO) sheets, where the GO was transferred to rGO during the sonication process. The obtained films were characterized using XRD and FTIR techniques. Optical absorption and transmission data were recorded via a UV–visible spectrophotometer and used to estimate various optical parameters. Increasing the amount of doped Fe 2 O 3 -rGO NPs in PVA decreased the ability of the prepared nanocomposites to allow visible light to pass through them. Solar material protection factor (SMPF) of PVA (11.93%) improved to 99.3%, corresponding to 2 wt% of Fe 2 O 3 -rGO NPs doped in the host matrix. The calculated values of the average refractive index are 2.18, 2.25, 2.36, 2.46, and 2.58, corresponding to 0 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, and 2 wt% of Fe 2 O 3 -rGO NPs doped in PVA. Therefore, the average refractive index showed a dependence on Fe 2 O 3 -rGO NPs. Low energy region (E < 2.4 eV) showed dielectric relaxation time- energy dependent behavior, whereas the high energy region (E > 2.4 eV) displayed dielectric relaxation time- energy independent behavior. Increasing the content of the doped NPs in PVA resulted in lowering the surface and volume energy loss.

This study effectively succeeded in synthesizing CdSe QDs and CdSe-SiO2 nanocomposites with controllable tunable size and spectacular morphology by using a solvothermal technique. UV-visible spectroscopy was used to study the effect of the growth time of CdSe QDs on the optical properties of its nanocomposite with SiO2. The structure of the prepared nanocomposites of CdSe-SiO2 was studied through the measurements of X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy FTIR. The Effective Mass Approximation model (EMA), Simple Exponential Function (SEF), and Polynomial Fitting Functions (PFF) were employed to compute nanoparticle sizes, providing particle sizes of 3.86, 4.19, and 3.72 nm, respectively, for CdSe-SiO2 nanocomposites (2 min). For the same nanocomposite, these theoretical values were comparable to the experimental values of the particle sizes deduced from measurements of TEM (4.5 nm) and XRD (3.4 nm). The deduced optical parameters of CdSe-SiO2 nano -composite, such as refractive index, dielectric constant, optical conductivity, electrical susceptibility, and some others, relied on the growth time of CdSe QDs. The absorption peaks of CdSe-SiO2 nanocomposites suffered from a bathochromic shift which increases as the growth time of CdSe QDs increases. Increasing the growth time of CdSe QDs resulted in increasing the reflection loss factor and decreasing the optical electronegativity. The values of the volume energy loss function (VELF) are greater than the values of the surface energy loss function (SELF) for the different nanocomposites. Consequently, the fast electrons miss their energies through their propagation within the studied materials more than through traveling on their surfaces. The enhancement of n values of nanocomposites of CdSe-SiO2 by increasing the growth time can candidate them to be usefully applied as antireflection coating for solar cells.(c) 2022 Elsevier B.V. All rights reserved.

CdSe-reduced Graphene Oxide (CdSe-rGO) nanocomposite was synthesized using a facile hot injection method with excellent control over the size and morphology. The superb distribution of the CdSe quantum dots (CdSe QDs) and the tightly anchoring to the graphene sheets enhance their optical properties. Therefore, the effect of reduced Graphene oxide (rGO) on the structure and optical properties of CdSe nanoparticles is studied by X-ray diffraction (XRD), UV-visible spectroscopy, and transmission electron microscopy (TEM). As well as Effective mass approximation model (EMA) and Polynomial Fitting Functions (PFF) were used to calculate the sizes of nanoparticles, yielding particle sizes ranging from 4.64 to 5.46 nm and 2.74-3.72 nm, respectively. These values were comparable to those obtained by TEM and XRD. Furthermore, the data revealed that the direct energy gap of the CdSe QDs was reduced from 2.33 eV for the smallest size to 2.17 eV for the largest size. The optical parameters of CdSe-rGO nanocomposite such as the refractive index and extinction coefficient were increased with the particle size growth. As well, optical dielectric constant and optical conductivity were improved due to the increase of the particle size of CdSe QDs in the CdSe-rGO nanocomposite. So, the capability of CdSe-rGO nanocomposite to tune the optical parameters makes it a suitable candidate for a wide range of applications, specifically optoelectronics. (c) 2021 Elsevier B.V. All rights reserved.

The Hematite (Fe2O3) nanoparticles and Fe2O3-reduced graphene oxide (rGO) nanocomposite were successfully synthesized via co-precipitation method. The rGO was used as passivation layer to improve the optical properties of the Fe2O3. X-ray diffraction, transmission electron microscopy, Raman, and Fourier transform-infrared spectroscopy were used to investigate the modification in the Fe2O3 structure in the presence of rGO. UV-visible absorption spectra were investigated, and the optical bandgap was determined. Using different relations like Moss, Rivandra, Anani, and others, the refractive index was calculated depending on the obtained optical bandgap. The refractive index values were compared with the data calculated from Duffy relation and good accordance was found between them. The optical bandgap and electronegativity were found to decrease by the addition of rGO in Fe2O3 matrix, while the refractive index was found to increase. Consequently, the Fe2O3-rGO nanocomposites capacity to control optical properties makes it a perfect contender for a variety of applications.

The novel polyvinyl alcohol (PVA) films reinforced with varied concentrations of Mn2O3/reduced graphene oxide (rGO) nanoparticles (NP) are prepared via the casting technique. A hydrothermal approach methodology is used to prepare manganese oxide reduce graphene oxide (Mn2O3/rGO) composite. The X-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscope (SEM), and optical microscope setups are used to study the impact of nanoparticles on the structure of the PVA matrix. The surface roughness was measured and found to increase with increasing NPs concentration in the polymer matrix. The UV–vis spectroscopy is used to investigate the optical absorption and transmission data for the prepared films. The addition of Mn2O3/rGO NP in the polymer matrix effects on the optical parameters like the absorption coefficient, optical bandgap, refractive index, and optical conductivity. The optical bandgap of PVA films with Mn2O3/rGO NP is lower than that of PVA pure. The refractive index and optical conductivity were tuned with the addition of Mn2O3/rGO NP. The PVA-Mn2O3/rGO films are promising material for various opto-electronic fields.

The effect size of CdS Quantum Dots (QDs) on thermal and photovoltaic parameters is investigated. CdS QDs were adsorbed onto TiO 2 electrodes using successive ionic layer adsorption and reaction (SILAR) to act as sensitizers of quantum dots solar cells (QDSSCs). The CdS QDs sizes are estimated using optical absorption spectra and application of effective mass approximation model (EMA) as well as high resolution transmission microscopes (HRTEM). The ratio of TiO 2 /CdS was confirmed by energy dispersive X-ray spectroscopy (EDX). Thermal parameters (thermal diffusivity α, thermal effusivity e and thermal conductivity k are measured by using Photoacoustic (PA) Technique. The photovoltaic parameters (open circuit voltage V oc , short circuit current density J sc , fill factor FF and efficiency η) of the assembled CdS QDs sensitized solar cells (QDSSCs) were determined under a solar illumination of 100 mW/cm2 (AM 1.5 conditions. Our results show that both the effective thermal conductivity k eff and efficiency η of CdS QDs deposited on TiO 2 increase as the size of CdS QDs is increased.