Mahammad Baghir Baghirov

High-dose gamma irradiation (0–1500 kGy) of GO–PVA–AgNW nanocomposites: XRD, Raman, UV-vis, TGA and EPR reveal increasing defects/radicals, decreasing crystallite size and band gap, and improved thermal stability.

Polyvinyl alcohol (PVA) nanocomposites reinforced with FeGaInS₄ and graphene oxide (GO) were investigated to enhance their structural and morphological properties for advanced functional applications. This work aims to understand how two different two-dimensional layered fillers influence the polymer composite’s structure, morphology, and potential application in optoelectronics and energy storage devices. The nanocomposites were synthesized using a solution-casting method and characterized by x-ray diffraction, Fourier-transform infrared spectroscopy, Raman spectroscopy, and field-emission scanning electron microscopy. The incorporation of FeGaInS₄ reduced the crystallite size from ∼30 nm to ∼8 nm and shifted the microstrain from tensile (0.34 × 10⁻⁶) to compressive (−17 × 10⁻⁶), indicating enhanced structural compaction due to polymer–filler interactions. Subsequent addition of GO at 1 wt.% and 3 wt.% further modified the strain to −10.28 × 10⁻⁶ and −6.47 × 10⁻⁶, respectively, attributed to improved interfacial bonding and stress relaxation. GO also decreased defect density and increased porosity by disrupting the PVA network. These synergistic effects between FeGaInS₄ and GO demonstrate the tunability of the nanocomposite structure, offering a pathway for tailored materials in optoelectronic and energy storage applications.

The rational integration of different-dimensional nanostructures offers a powerful platform for engineering synergistic functionalities in photocatalysis. Herein, we report the controllable synthesis of novel 2D/1D graphene/silver–silver sulphide (Ag–Ag₂S) hybrid nanocomposites, wherein 1D Ag–Ag₂S nanowires (NWs) are uniformly anchored onto conductive graphene sheets, affording a hierarchical hybrid structure with tailored optoelectronic properties. Structural characterization via X-ray Diffraction (XRD) confirmed the coexistence of crystalline Ag, Ag₂S, and Ag₂O phases, evidencing both hybridization and partial oxidation during growth. Complementary Scanning Electron Microscopy (SEM) imaging revealed a homogeneous distribution of NWs across the graphene scaffold, ensuring maximized interfacial contact. Optical investigations demonstrated distinct band gap features (2.5 eV for Ag₂S, 3.8 eV for Ag NWs, and 4.6 eV for Ag₂O). In comparison, the composite exhibited dual transitions at 3.28 eV and 4.72 eV, attributed to interfacial charge transfer between Ag₂S and graphene, alongside enhanced plasmonic carrier dynamics. FTIR analyses further corroborated the hybrid composition, highlighting O–H and CC stretching vibrations of graphene, CO bands from surface PVP ligands, and Ag–S/Ag–O vibrational modes consistent with XRD assignments. Harnessing these tailored structural and electronic attributes, the graphene/Ag–Ag₂S heterostructures exhibited markedly superior photocatalytic activity toward methylene blue (MB) degradation, achieving a maximum efficiency of 89.55% under acidic conditions (pH 3) after 300 min of irradiation. Kinetic analysis revealed the highest rate constant (0.386 min⁻¹) for the graphene/Ag–Ag₂S nanocatalyst in acidic medium, surpassing both pristine Ag NWs and Ag–Ag₂S. This work highlights the potential of spatially engineered graphene-based heterostructures to modulate band structures, enhance charge carrier transport, and thereby improve selective photocatalytic dye removal.

In this study, GO/PVA/AgNWs nanocomposites were exposed to gamma irradiation at doses of 8, 25, and 50 kGy to investigate the effects of gamma radiation on their structural and morphological properties. Structural modifications induced by irradiation were examined using X-ray diffraction (XRD) analysis and Raman spectroscopy, while morphological changes were evaluated through scanning electron microscopy (SEM). The findings demonstrate that gamma irradiation significantly affects the crystallinity of the nanocomposites. Although no considerable morphological alterations were observed, Raman spectroscopy confirmed the presence of radiation-induced structural defects. Analysis of the I_D/I_G ratio revealed that the most prominent defect formation occurred in the sample irradiated with 8 kGy, which exhibited an I_D/I_G ratio of 1.07. Furthermore, the study underscores the influence of gravitational forces during the composite fabrication process, as evidenced by the preferential accumulation of fillers in the lower regions of the nanocomposites. This phenomenon was validated through both XRD and SEM analyses. Overall, the study offers valuable insights into the role of gravitational effects in composite formation and elucidates the influence of low-dose gamma irradiation on the structural integrity, morphology, and optical characteristics of GO/PVA/AgNWs nanocomposites.

A new method for creating AgNWs/PVA/Ag ₂ S type asymmetric structures.

In this study, the synthesized GO/AgNWs composites were sulfidized by exposure to H₂S gas, and their physical properties were compared with the original form.

In this study, a modified Hummers' method was employed to prepare graphene oxide (GO), which was then mixed with polyvinyl alcohol (PVA) polymer at varying weight concentrations (1 wt% and 5 wt%).

The present research involves producing graphene oxide (GO) using the Hummers method, generating a composite using GO and PVA, and analyzing these composites’ structural and optical characteristics. PVA and GO were used in varied percentages to deal with the issue of how the features of GO/PVA alter depending on concentration. The impact of thermal annealing on the structure and optical characteristics of GO/PVA materials at various concentrations were also investigated. UV-VIS was used to investigate the band gap value of GO/PVA composites. The band gap value changed due to an increase in the concentration of GO in the composites in the PVA and the impact of thermal annealing. The band gap value, specific resistance, and dielectric constant were all found to be well controlled by varying the thermal annealing temperature and the concentration of GO in this case. Differential Scanning Calorimetry (DSC) and thermogravimetric analysis (TGA) were performed on pure PVA and GO/PVA samples in various percentages of GO in order to examine the effect of temperature on the physical properties of (n = 1, 2, 3, 5, 20%) nGO%/PVA nanocomposites. Thermal stability increased as the fraction of GO in the PVA polymer matrix increased.