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In this study, the electrospinning technique was successfully used to fabricate α-Fe2O3 nanofibers. Fe(NO3)3-9H2O, polyvinyl pyrrolidone (PVP), and N,N-dimethylformamide (DMF) were used as sol for spinning nanofibers, and the final product was calcined at three different calcination temperatures 500 °C, 600 °C, and 700 °C. Nanofiber samples were characterized by X-ray diffraction (XRD), Fourier Transform Infrared (FT-IR), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), and vibrating sample magnetometer (VSM) techniques. In view of the structural and chemical properties, XRD and FT-IR confirmed the formation of well-crystalline α-Fe2O3 nanofibers without any phase transition after thermal treatment. X-ray diffraction patterns shows single rhombohedral phase of the α-Fe2O3 fibers. It is evident from the Rietveld refinement of X-ray diffraction data that calcination temperatures have influenced on the microstructural parameters of nanofibers. SEM observations revealed the formation of smooth, granule, and beaded free fibers after calcination of as-spun fibers. DRS measurement indicates different electronic transition in the wavelength interval 270–750 nm. VSM analysis shows ferromagnetic behavior of the prepared fibers. [ABSTRACT FROM AUTHOR]

A γ-Fe2O3/carbon nanofiber composite was prepared by electrospinning a mixed solution of iron nitrate nonahydrate (Fe(NO3)3·9H2O) and polyvinylpyrrolidone (PVP) with subsequent treatment under an Ar atmosphere. A morphology study of the γ-Fe2O3/carbon nanofiber composite using FE-SEM, TEM, and AFM techniques confirms the formation of randomly oriented carbon fibers that include γ-Fe2O3 nanoparticles, along with an agglomeration in the fibrous environment and surface roughness of the fibers. Structural analysis from the XRD patterns showed that the synthesized sample was ferric oxide having a gamma phase tetragonal crystal structure and amorphous behavior of carbon. FT-IR spectroscopy further demonstrated the presence of functional groups corresponding to γ-Fe2O3 and carbon in the γ-Fe2O3/C structure. DRS spectra of the γ-Fe2O3/C fibers indicate absorption peaks related to γ-Fe2O3 and carbon in the γ-Fe2O3/carbon composite. In view of the magnetic properties, the composite nanofibers showed a high saturation magnetization Ms of 53.55 emu g−1. [ABSTRACT FROM AUTHOR]

Zinc oxide/zirconia (ZnO:ZrO2) composite fibers (Fs) with different molar ratios, prepared by using the electrospinning technique, were deposited onto the n-Si as ZnO:ZrO2 composite Fs/n-Si hybrid heterostructures. According to the molar ratios of ZnO:ZrO2 (3:1), (1:1), and (1:3), the ZnO:ZrO2 composite Fs/n-Si devices were labeled D5, D6, and D7, respectively. In the dark, all three devices exhibited very good rectification, such that the rectification ratios were calculated as 4.76 × 104, 4.62 × 104, and 8.08 × 105, for the D5, D6, and D7 devices, respectively. Since it has both a higher rectification ratio and a self-powered mode, the electrical and optical properties of the D7 device were studied in detail. From the time-dependent I–V measurements, it was observed that the instrument remained stable after 30 days. It was seen that the device has remarkable photosensitivity for visible light, such that the ON/OFF ratio, responsivity, and specific detectivity were calculated to be 1.14 × 104, 1.59 mA/W, and 3.50 × 1011 Jones, under the illumination of 150 mW/cm2, (at—0.1 V). Furthermore, capacitance, conductance, and impedance measurements have been performed. In summary, the proposed ZnO:ZrO2 composite Fs/n-Si device is believed to provide new insights into developing low-cost, efficient, and self-powered photodetectors for high-performance optoelectronic applications in the future. [ABSTRACT FROM AUTHOR]

This paper reports a very simple and cost effective electrospinning technique for the preparation of mixed oxides composite fibers, ZnO–BaCO3, followed at calcination temperature of 500 C. X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV–Vis diffuse reflectance spectroscopy (DRS) are used to investigate the structural, morphological and optical properties of the composite fibers. The results show good correlation between the X-ray diffraction analysis and the optical properties of different weight percentages of ZnO on BaCO3. Also, SEM results indicate that the morphology of the ZnO–BaCO3 composite fibers were influenced by changing of the molar ratio of Zn:Ba. [ABSTRACT FROM AUTHOR]

Electrospinning derived nanostructured CeO 2 and ZnO CeO 2 composite fibers have been successfully fabricated, followed by a subsequent heat-treatment. X-ray line profile analysis is applied to the X-ray diffraction data collection for determination of microstructure parameters both area -and volume-averaged apparent crystallites size based on spherical crystallites with lognormal size distribution. The surface morphologies of the prepared samples were examined with scanning electron microscope (SEM). To gain insight into the optical properties of the fabricated nanofibers, the UV–vis diffuse reflectance absorption spectrums were measured. The correlation between the structural and optical properties is discussed. [ABSTRACT FROM AUTHOR]

It is well known that metal/Tin-dioxide/metal sandwich structures exhibit a field-assisted lowering of the potential barrier between donor-like center and the conduction band edge, known as the Poole-Frenkel effect. This behavior is indicated by a linear dependence of Iog J on V1/2, where J is the current density, and V is the applied voltage. In this study, the electrical properties of Cu/nano-SnO2/Cu sandwich structures were investigated through current-voltage measurements at room temperature. Also, an attempt to explore the governing current flow mechanism was tried. Our results indicate that noticeable feature appearing clearly in the current-voltage characterization is the Poole-Frenkel and space-charge-limited conduction mechanisms. [ABSTRACT FROM AUTHOR]

The electrospinning technique has been successfully employed for the fabrication of porous BaMnO3 nanofibers, followed by different thermal treatment. The samples were studied by X-ray diffraction (XRD), scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDX), Fourier transform infrared (FT-IR) spectroscopy, and diffuse reflectance spectroscopy (DRS). The XRD pattern shows that the organics were completely removed in sample calcined at 800 °C and the hexagonal BaMnO3 nanofibers were obtained. The microstructural parameters such as crystallite size and lattice strain contributions to line broadening were estimated using Williamson-Hall (W-H) analysis. The morphology and average diameters of the prepared nanofibers were estimated from the SEM images. The SEM images of the calcined samples show porous structure. The optical properties were studied using UV-Vis diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) spectra. The optical bandgap of the calcined nanofibers decreased with an increase in calcination temperature from 700 to 800 °C. The PL spectrum shows that BaMnO3 nanofibers increased the radiative centers. We thus conclude that BaMnO3 nanofiber shows luminescent property. [ABSTRACT FROM AUTHOR]

This study provided a promising way to fabricate low-cost and high-performance Poly (vinyl alcohol)-reduced graphene oxide (PVA-RGO) nanofibers/n-Si heterojunction photodetector. For this purpose, the hybrid heterojunction with a very-high rectification ratio (2.4 × 10 6 ) was achieved by successfully coating PVA-RGO nanofibers on n-Si wafer by electrospinning method. When the electro-optical analysis of the fabricated heterojunction photodetector under visible light depending on the light intensity, ultraviolet (UV) and infrared (IR) lights was examined in detail, it was observed that the photodetector exhibited both self-powered behavior and very high photo-response under each light sources. However, the highest optical performance was obtained under UV (365 nm) originated from PVA-RGO layer and IR (850 nm) light from both interfacial states between PVA-RGO nanofibers and Si and from Si layer. Under 365 nm UV light, the maximum performance values of R, D, ON/OFF ratio, normalized photo-dark-current ratio and external quantum efficiency (%) were obtained as 688 mA W -1 , 1.15 × 10 15 Jones, 2.49 × 10 6 , 8.28 × 10 10 W -1 and 234%, respectively., (© 2024 IOP Publishing Ltd.)

A γ-Fe 2 O 3 /carbon nanofiber composite was prepared by electrospinning a mixed solution of iron nitrate nonahydrate (Fe(NO 3 ) 3 ·9H 2 O) and polyvinylpyrrolidone (PVP) with subsequent treatment under an Ar atmosphere. A morphology study of the γ-Fe 2 O 3 /carbon nanofiber composite using FE-SEM, TEM, and AFM techniques confirms the formation of randomly oriented carbon fibers that include γ-Fe 2 O 3 nanoparticles, along with an agglomeration in the fibrous environment and surface roughness of the fibers. Structural analysis from the XRD patterns showed that the synthesized sample was ferric oxide having a gamma phase tetragonal crystal structure and amorphous behavior of carbon. FT-IR spectroscopy further demonstrated the presence of functional groups corresponding to γ-Fe 2 O 3 and carbon in the γ-Fe 2 O 3 /C structure. DRS spectra of the γ-Fe 2 O 3 /C fibers indicate absorption peaks related to γ-Fe 2 O 3 and carbon in the γ-Fe 2 O 3 /carbon composite. In view of the magnetic properties, the composite nanofibers showed a high saturation magnetization M s of 53.55 emu g -1 .

A BaCO 3 /BaSnO 3 /SnO 2 nanocomposite has been prepared using a co-precipitation method without adding any additives. The prepared sample was characterized by using X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), Fourier-transform infrared (FT-IR) spectroscopy, energy dispersive X-ray spectroscopy (EDS) and Raman spectroscopy. Detailed studies on the dielectric and electrical behavior (dielectric constant, complex impedance Z *, ac conductivity, and relaxation mechanisms) of the nanocomposite have been performed using the nondestructive complex impedance spectroscopy technique within the temperature range 150-400 K. The dielectric constant of the sample as a function of temperature showed the typical characteristics of a relaxor. The maximum dielectric constant value was observed to depend on frequency. The non-monotonic relaxation behavior of the prepared nanocomposite was evidenced from the spectra of loss tan, tan( δ ). The relaxation kinetics was modeled using a non-Arrhenius model., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)