Formation Of Electron-hole Pairs Research Articles

Study of the Electrophysical Properties of "Surkhon-104" Grade Cotton Fibers Alloyed with \(KMnO_4\)

In this article, the physical properties of cotton fibers sort of "Surkhon-104" with thermal treatment were studied. The main results of the research are as follows. The electrophysical and photoelectrical properties of cotton fibers doped with KMnO4 were studied. The research was carried out in the temperature range of 300-360 K and voltage in the range of 0-100 V. Temperature dependence of electrical conductivity of cotton fibers was studied. It was proved that the current flowing from all samples prepared as a research object obeys Ohm's law. It was found that the photoconductivity caused by ultraviolet and visible light in the cotton fibers sample is mainly related to the formation of inter-zone electron-hole pairs. it was found that the electrical conductivity increased significantly due to the photogeneration of charge carriers. The long-term relaxation of photoconductivity was determined, which is related to the localization of electrons to Et2=Ec-1,5 eV levels.

Computational exploration of oxide-based double perovskites Sr2MgWO6 and Ba2BiVO6 for photocatalysts for sustainable degradation processes

First-principles calculations have been utilized to investigate the photocatalytic degradation, structural properties, electronic properties, population inversion, effective mass, redox potential, and optical properties of oxide-based double perovskites Sr2MgWO6 and Ba2BiVO6. The calculated value of τG is 0.83 for Sr2MgWO6 and 0.97 for Ba2BiVO6. The electronic properties indicate the semiconducting behavior of studied materials, which enable the efficient formation of electron-hole pairs upon photon absorption. The photocatalytic efficiency of perovskite materials was determined by studying the effective mass ratio. The optical parameters exhibit a strong correlation with the underlying electronic band structure. The electronegativity values were computed to be 5.292 eV and 5.206 eV for Sr2MgWO6 and Ba2BiVO6, respectively. The conduction band edges value are found to be −0.523 eV for Sr2MgWO6 and 0.146 eV for Ba2BiVO6. Based on their redox potentials, the Sr2MgWO6 and Ba2BiVO6 oxide perovskites have a high potential for use in photocatalytic applications, specifically in the generation and degradation of organic pollutants. These perovskites degrade organic pollutants with high efficiency and can effectively contribute to environmental treatment. Their strong capacity for reduction and oxidation reactions gives them an advantageous capability to degrade organic pollutants.

Enhanced Photocatalytic Degradation of Organic Pollutants Using Iron Lanthanum Oxide Nanoparticles

This study investigates the synthesis, characterization, and photocatalytic performance of iron lanthanum oxide nanoparticles (FeLO NPs) tailored for environmental remediation applications. The nanoparticles were synthesized using a co-precipitation method involving ferrous and lanthanum nitrates, followed by pH adjustment and calcination. Characterization techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR) were employed to analyze the structural and morphological properties of the nanoparticles. XRD confirmed the crystalline nature of FeLO NPs with peaks corresponding to standard indices, while SEM images revealed a heterogeneous surface topology conducive to catalytic activity. FTIR analysis detected functional groups and bonding interactions indicative of the complex molecular composition of the nanoparticles. The Brunauer-Emmett-Teller (BET) method determined a surface area of 2.43 m²/g. Photocatalytic testing using methylene blue (MB) under UV and visible light showed that FeLO NPs achieved up to 90% degradation of the dye, highlighting their effectiveness in pollutant breakdown. The degradation mechanism involved the formation of electron-hole pairs, facilitating radical generation and subsequent pollutant decomposition. This study underscores the potential of FeLO NPs as efficient and sustainable photocatalysts for the treatment of dye-polluted wastewater.

Enhancing the Photocatalytic Activity and Luminescent Properties of Rare-Earth-Doped CeO2 Nanoparticles

Our study is focused on the structural and morphological characteristics, optical behaviour and photocatalytic properties of undoped and 5 at% Eu3+-, Gd3+- and Y3+-doped CeO2 nanoparticles prepared by a green hybrid sol-gel combustion method. Several techniques such as X-ray diffraction powder (XRD), Transmission Electron Microscopy (TEM), UV-Vis spectroscopy, Photoluminescence spectroscopy (PL) and Electron Paramagnetic Resonance (EPR) have been used to investigate the obtained samples. Moreover, the correlation between the characteristics and properties has been studied. The nanoparticles observed by TEM exhibit a pseudo-spherical shape, except for Y3+-doped CeO2, which presents an acicular shape. The average size of undoped and rare-earth-doped CeO2 nanoparticles is below 10 nm, in good agreement with the calculations performed based on XRD analyses. From UV-Vis analyses it has been deduced that with doping the band gap energy decreases, which shows that additional levels are introduced by doping into the CeO2 band gap. The EPR spectra evidence similar behaviour for all doped samples. The photocatalytic activity was evaluated by the degradation of rhodamine B (RhB) under UV light irradiation. The photodegradation mechanism has been studied in depth based on the formation of electron-hole pairs, and to evidence the reactive oxygen species, ESR coupled with spin-trapping experiments was performed. In the case of Y-doped CeO2 nanoparticles, the generation of both •OOH and •O2− radicals involved in RhB photodegradation was highlighted.

Highly efficient ZnFe2O4 decorated g-C3N4/GO with biomedical and photocatalytic activities

In this work, a novel magnetic composite was synthesized using graphene oxide (GO), graphitic carbon nitride(g-C3N4), and zinc ferrite (ZnFe2O4) for photocatalytic and biomedical functions. The synthesized nanocomposite (g-C3N4/GO/ZnFe2O4) was characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray (EDX), UV–Vis diffuse reflectance spectra (DRS), vibrating sample magnetometer (VSM), Brunner-Emmett-Teller theory (BET), and photoluminescence (PL) techniques. Decorating g-C3N4 and GO by ZnFe2O4 as a multi-component photocatalyst with a simple and cost-effective method in our work shows high efficiency, antibacterial, and anticancer activity. The outcome of using the nanocomposite as a novel heterojunction structure, in comparison to other individual photocatalysts, has shown great activity in degrading methylene blue (MB) due to the formation of electron-hole pairs. GO improved the photocatalyst adsorption capacity and life of charge carriers, facilitating the transfer of electrons. Also, ZnFe2O4 increased the separate charges and reusability process by making heterojunction structures. The dye degradation process attained 98 % promising efficiency in only 60 min and just 3.7 % degradation after 30 min in dark conditions. The Plausible mechanism shows the Z-scheme route. Also, practical factors such as pH, concentration, dosage, and scavenger were obtained, and the optimal values were 10, 20 mg/L, 0.3 g/L, and EDTA (Ethylenediamine tetraacetic acid), respectively. The reusability of nanocomposite was also analyzed in 6 cycles. Finally, the nanocomposite made the area of inhibition on Pseudomonas aeruginosa (Gram-negative bacteria) and Bacillus cereus (Gram-positive bacteria) about 18 ± 0.5 mm and 14 ± 0.2 mm, respectively. Also, the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) tetrazolium assay was examined. The MTT assay for breast cancer cell lines showed the survival percentage of cells is between 99.2 % and 61.4 %, so it can be applied as a carrier.

Structural, optical, and thermoluminescence characterizations of 1 mol% Dy3+ion-activated Fluro Boro-phosphate glass for photonic devices

A novel Fluro boro-phosphate host matrix doped with the 1 mol% of Dy3+ ions (50B2O3 + 20P2O5 + 10TiO2 + 10SrCO3 + 4BaF2 + 5BaCO3 + 1Dy2O3) was prepared using a conventional melt-quenching mechanism, and its structural characteristics were explored through the Powder-XRD, FT-IR, FT-Raman, EDAX and SEM spectroscopic analysis. The XRD spectrum of the glass confirmed its non-crystalline or amorphous structure. FT-IR and FT-Raman spectrum studies revealed that various borate and phosphate groups present with a variety of stretching and bending vibrations. Scanning Electron Microscope (SEM) and Energy Dispersive X-ray analysis (EDAX) analysis have been used to examine the surface morphology and the presence of elements, respectively in the prepared glass. The optical absorption spectrum was used to explore the electronic band structure through the measurements of optical band-gap energy and Urbach energy. The luminescence spectrum reveals the emission characteristics of Dy3+ ions due to the electric-dipole and magnetic-dipole transitions. It is found that the decay time of the 4F9/2 excited level at a concentration of 1 mol% Dy3+ in the glass matrix is tri-fit non-exponential. The CIE chromaticity coordinates and the concentration influence on Y/B intensity ratios were computed for the creation of white light from the luminescence spectrum. The present work also discusses the findings after figuring out the correlated color temperature associated (CCT) with the color purity (Pe). The Thermoluminescence (TL) characteristics and the kinetic parameters of the glass were studied after the γ-irradiation with a dose of 2 kGy. EPR investigation revealed the paramagnetic characteristics through the hyperfine structure of Dy3+ ions and the electron-hole pair formation upon irradiation in the glass matrix.

Photocatalytic Th(IV) removal: Unleashing the potential of amidoxime-modified graphitic carbon nitride photocatalyst

g-C3N4-AX photocatalyst was synthesized using a hydrothermal approach, with urea as a precursor, for the removal of Th(IV) in aqueous solution. The results of the experiment indicated that the addition of amidoxime to g-C3N4 altered its photocatalytic characteristics, resulting in a narrower band gap reduced from 2.75 eV to 2.7 eV, and faster formation of electron-hole pairs. The g-C3N4-AX photocatalyst exhibited remarkable uptake capacity with 71.09 mg.g−1 within 120 min. The excellent performance of g-C3N4-AX was mainly attribute to its effective absorption of visible light, facilitated by the narrow band gap. Therefore, this study proposes the potential of g-C3N4-AX can be efficiently adapted as a visible light-responsive catalyst for the application in radioactive effluent treatment.

Piezopotential and vacancies co-enhanced sonodynamic response of a ZnO-TiO2-x heterojunction array for osteointegration in MRSA-infected osteomyelitis

Preventing multidrug-resistant bacteria-related osteomyelitis and simultaneously improving osseointegration are in great demand for orthopedic implants. Herein, an ultrasound (US)-responsive array of nanorod-like core–shell heterojunctions is developed on Ti substrate, in which oxygen vacancies (OVs) and residual compressive stresses are respectively introduced into TiO2 shells and ZnO cores via annealing in argon and ice cooling. The OVs narrow TiO2 band gap to enhance the formation of US-excited electron-hole pairs, while the ZnO-generated piezoelectric field by the residual compressive stress efficiently separates these electron-hole pairs. The combination of these two effects in the array leads to much more generation of reactive oxygen species than either under US irradiation, in which the piezoelectric field-derived separation of electron-hole pairs plays a crucial role. Consequently, the array exhibits high bacteria-killing and biofilm-eradicating efficacy of methicillin-resistant Staphylococcus aureus (MRSA), possessing strong osseointegration in MRSA-infected osteomyelitis of rat.

Facile synthesis of silver chloride-polyaniline nanocomposites and its photocatalytic activity for the degradation of methylene blue

Herein, we report a green and an effective strategy for the synthesis of polyaniline-silver chloride (AgCl@PANI) nanocomposites by using facile in-situ chemical oxidative polymerization method in the presence of as-synthesized silver nanoparticles (Ag NPs) for the study of their photocatalytic activity towards the photodegradation of methylene blue (MB) under UV irradiation. The contents of Ag NPs varied from 2% to 6% during polymerization reaction to get AgCl@PANI nanocomposites. These synthesized polymer nanocomposites were characterized for their structural and optical properties, thermal stability, dc conductivity and photocatalytic activity by FT-IR spectroscopy, XRD, UV–Vis spectroscopy, TGA, SEM, standard four probe method and the photodegradation activity of MB, respectively. XRD analysis confirm the successful formation of AgCl@PANI nanocomposites without the presence of additional phases. TGA shows that AgCl@PANI nanocomposites have excellent thermal stability due to the barrier effect of AgCl moieties bounded with in the polymer chain and the strong physiochemical interactions between PANI and AgCl as inferred from FT-IR and UV–vis analysis. Under UV irradiation, the AgCl@PANI nanocomposite, with 4 wt% of Ag NPs (AgCl@PANI-4%), demonstrated excellent photocatalytic activity for MB degradation with the photodegradation percentage of ∼ 99 % in 20 min. The experimental findings illustrate that the superior photocatalytic activity of AgCl@PANI nanocomposites is owing to incorporation of AgCl moieties in the polymer structure, less needed energy for the formation of electron-hole pairs in the quinoid ring of PANI in the UV-region, enhanced light absorption owing to smaller grain size morphology, high surface area of the nanocomposite and high electrical conductivity (128 mS.cm−2). These results suggest the potential of these synthesized conjugated polymer-based nanocomposites as a photocatalyst for cost-effective and efficient wastewater treatment for the industrial applications.

Toward Ga‐Free Wavelength Extended 2.6 µm InAsP Photodetectors with High Performance

AbstractShort‐wavelength infrared (SWIR) photodetectors are of great interest owing to their unique advantages of SWIR imaging such as better penetration ability and improved sensitivity that allow high‐resolution imaging. Commercially, extended InxGa1‐xAs heterojunction detectors with cut‐off wavelengths beyond λc = 1.7 µm are incorporated into SWIR imagers. However, their large dark current and limited cut‐off wavelength tunability prevent their widespread use in SWIR imaging. Herein, a novel InAs0.85P0.15 homojunction detector with λc = 2.6 µm is achieved through lattice and bandgap engineering with well‐designed InAsyP1‐y metamorphic buffers. Compared to conventional In0.83Ga0.17As/InP detectors with a lattice mismatch of f = 2.0%, the InAs0.85P0.15 detector with f = 2.7% exhibits full strain relaxation and lower surface roughness (2.4 nm due to its superior crystallinity). Photocarrier generation in the InAsP detector is more efficiently supported by a smaller entropy for electron–hole pair formation. The lower trap density and longer carrier lifetime of the InAsP detector decrease the dark current, leading to high uniform detectivities of ≈1.0 × 109 cm Hz1/2 W−1 over a wider voltage range at 300 K. Such an InAsP metamorphic detector with excellent photodetection capabilities is expected to find applications in the implementation of large‐format focal plane arrays for extended SWIR imaging.

An ab-initio investigation of structural, electronic, optical and elastic properties of novel double Vacancy-ordered perovskite Cs2MoI6 for photocatalytic application

Manipulation of appropriate photocatalyst is a core issue for applications in photocatalytic degradation of contaminants. In this context, the double perovskite Cs2MoI6 exhibit encouraging photocatalytic properties, suggesting it may be useful for photocatalytic water-splitting and contaminants degradation. Here, we have analyzed the structural, electrical, optical, and elastic characteristics of Cs2MoI6 employing first-principles density functional theory computations. According to structural property studied compound is cubic with 7.75Å lattice constant. There have determined through research that the perovskite Cs2MoI6 has mechanical stability and anisotropic elastic characteristics. Upon inspection of its electronic band structure, Cs2MoI6 is originating to be a semiconductor with direct bandgap energy of 1.33eV. With a small effective mass of hole carriers and a narrow bandgap, electrons can easily move to the surface, boosting the photocatalytic rate. The formation of electron-hole pairs upon photon absorption, as predicted by the relevant band edge potential, indicates the substance's capability to splitting water into its constituent H2 and O2 molecules. Our results are predictable to subsidize the improvement of efficient photocatalytic devices for use in degradation of ecological contaminants. Based on the achieved tunable moderate bandgap and noble optical absorption in the UV region, the Cs2MoI6 proposed for utilization in various thermoelectric, electrical, optical and optical applications, particularly in novel energy generation applications.

Development of an electron track-structure mode for arbitrary semiconductor materials in PHITS

Abstract Optimizing the design of semiconductor detector requires an electron track-structure code that can trace an incident electron motion with energies down to a few eV and simulate the production process of excited electrons in semiconductors. We therefore developed an Electron Track Structure mode applicable to ARbitrary Targets (ETSART) and implemented it into Particle and Heavy Ion Transport code System (PHITS). ETSART can simulate the electrons’ motion in arbitrary semiconductor materials using their bandgap energies. The accuracy of ETSART was validated by comparing the calculated electron path lengths in semiconductor materials with the corresponding data in the ICRU Report 37. Using ETSART, we also computed the mean energy required to produce an electron–hole pair (epsilon value) in various semiconductors and found that the epsilon value varies nonlinearly with the bandgap energy. Thus, ETSART can be useful for initial and mechanistic evaluations of electron–hole pair formation in new materials.

Construction of novel an in-situ m-BiVO4/t-BiVO4 isotype heterojunction photocatalyst for improved visible light-dependent degradation of dye

In this article, we have studied the photocatalytic characteristics of isotype heterostructure Bismuth vanadate BiVO4 (m-BiVO4/t-BiVO4). The isotype Bismuth vanadate m-BiVO4/t-BiVO4 (MTBV) was formed by a facile hydrothermal method. It was observed that the crystalline phase of isotype MTBV could be controlled by modifying the pH values of the precursors in the hydrothermal method. The isotype MTBV heterojunction was investigated for its physicochemical features by different techniques including X-ray powder diffraction (XRPD), Field emission scanning electron microscopy (FESEM), Energy dispersive microscopy (EDS), Fourier transfer infrared (FTIR) spectroscopy, UV–visible diffuse reflectance spectroscopy (UV–Vis DRS), Photoluminance (PL), and Electrochemical impedance spectroscopy (EIS). Photocatalytic degradation of Congo red (CR) dye under visible light irradiation was used to determine the photocatalytic activity of a well-developed MTBV heterostructure. The isotype MTBV phase resulted in an increased response due to a faster electron-hole pair formation rate by reducing charge recombination processes, a reduction in optical energy band gap (2.52 eV), and good compatibility between Preston t-BiVO4 and m-BiVO4 photocatalyst. In 1 hr, the optimized isotype MTBV heterojunction showed a CR degradation of 98%. According to the results of the PL, EIS, and UV–Vis studies, isotype MTBV might be an excellent option for a blue/green visible light-dependent optical photocatalyst. A feasible photocatalytic mechanism was suggested and discussed in particular to relate the physiochemical properties and photocatalytic properties; furthermore, kinetics decomposition process study, scavenger effect, dye concentration, catalyst dose effect, reusability and stability were checked, respectively.

Suppression of ferromagnetism due to N co-doping in Cr(II)-doped ZnS nanowires and their optical properties: Insights from density-functional calculations

Spin-related optical properties will be the main basis for future information technology, but they require microscopic ferromagnetic and anti-ferromagnetic couplings between the d-states of the transition metal ions or magnetic interaction between excitons and magnetic ions, all of which remain unclear in these diluted magnetic semiconductors.In this work, we studied the influence of Cr doping and co-doping of Cr with N on the electronic, optical, and magnetic properties of ZnS nanowires using spin-polarized density functional theory. According to our findings, Cr(II) doping induces a half-metallic state with a magnetic moment of 4 μB per Cr(II) ion. The ferromagnetic behaviors and high Curie temperature in undoped Cr(II)-doped ZnS nanowires were suppressed due to the hole-carriers introduced by N co-doping. The band-coupling model was used to explain ferromagnetic (FM) stability in Cr(II)-doped nanowires with and without N co-doping. The optical properties of undoped ZnS nanowire, doped, and co-doped wires have been computed, and it is found that the bandgap (3.49 eV) exhibits a red shift upon Cr(II) doping, with the energy bandgap falling from 3.49 to 3.20 eV, and the bandgap being further decreased to 3.05 eV upon N co-doping. Compared with pure ZnS nanowires, mono- and co-doped nanowires have a higher electron-hole pair formation rate and better optical properties. The d-state to d-state transitions of the Cr(II) ion in the wire occur in the mid-infrared and near-infrared red regions and are shifted to the high energy side by N co-doping. Furthermore, we correlated the optical band gap of ZnS nanowire and the d-d transition peak of Cr ions under different modes of magnetic coupling, and we found that the optical band gap and d-state to d-state transition peaks of Cr(II) ions shift to lower and higher energies in FM and AFM configurations, respectively. Such a shift in bandgap and d-d transition peaks of Cr(II) ions in the FM and AFM states of the far configuration was not observed.

Single-layer ZnGaInS4: Desirable bandgap and high carrier separation efficiency for optoelectronics

Two-dimensional optoelectronic materials with desirable bandgaps and high carrier separation efficiency are in urgent need. Herein, single-layer ZnGaInS4 is designed and thoroughly studied by first-principles calculations. Our calculations reveal the excellent stability of single-layer ZnGaInS4, and the small cleavage energy demonstrates the feasibility to exfoliate single-layer ZnGaInS4 from bulk counterparts. At the HSE06 level, single-layer ZnGaInS4 has a moderate bandgap of 2.05 eV, and its valence band maximum and conduction band minimum are spatially separated, thus impeding the electron-hole pair formation and enhancing the photoelectronic performance. In the visible region, single-layer ZnGaInS4 exhibits an optical absorption coefficient of ∼ 105 cm−1. Notably, single-layer ZnGaInS4 possesses high electron carrier mobility and low hole carrier mobility, further affirming the effective carrier separation. Another attractive characteristic is that single-layer ZnGaInS4 has anisotropic hole mobility. The desirable bandgap and high separation efficiency of generated carriers, together with abundant optical absorption, promise single-layer ZnGaInS4 is a hopeful candidate in atomic-thick optoelectronic devices.

Modelling and numerical simulations of eco-friendly double absorber solar cell “Spiro-OmeTAD/CIGS/MASnI3/CdS/ZnO” and its PV-module

A broad study for design of higher efficiency modules based on low-cost, non-toxic Au/Spiro-OmeTAD/CIGS/MASnI3/CdS/ZnO/FTO tandem configuration solar cells has been conducted using solar cell capacitance simulator package “SCAPS-1D”. For the cause of highly efficient device performance, the selection of suitable layer materials such as “ZnO” as electron transport layer “ETL”, “CIGS” and “MASnI3→CH3NH3SnI3” as absorber, “Spiro-OmeTAD” as hole transport layer “HTL”, and CdS as active buffer layer material have been developed. The structural layout of the recommended composition was enhanced by variation in thickness of the specified layers, different back contact layers and temperature. The power conversion efficiency “PCE” was found to be 36.38%, along with other electrical parameters such as short-circuit current density “Jsc” of 48.28 mA/cm2, open-circuit voltage “Voc” of 1.38 V, and fill factor of 54.24% for optimized layer thickness of 0.084 μm for “HTL”, 0.051 μm for ETL”, 0.028 μm for buffer layer, 2.10 μm and 1.51 μm for CIGS and CH3NH3SnI3 absorber layers respectively. The overall device performance in perspective of charge carrier generation and recombination was investigated in depth. The improvement of diffusion length has increased the charge carrier's generation around 3.69 μm and the recombination rate was found at a lower value of 2.2 μm which overall enhance the device performance. At standard conditions, the formation of supplementary electron-hole pairs by varying the absorber layers thickness shows the maximum extent for Jt, FF% and PCE% during optimized investigation. A module of dimensions (2.2 × 1.1) m consisting of 72 cells in series was configured in PVsyst software to get the panel performance. Input parameters obtained through solar capacitance simulator were incorporated to evaluate module performance and output power by variation in solar irradiation and temperature. Yearly performance ratio for home location has been explored and reported.

The effect of Cobalt-60 gamma irradiation on dielectric parameters and junction features of the Al/Orange G/p-Silicon diode

In this study, an Al/Orange G (OG)/p-Si device was constructed using a solution processing method. The electronic and interfacial features of the Al/OG/p-Si structure under 60Co gamma radiation were determined using the Cheung and Norde techniques. The barrier height (ϕ b), ideality factor (n), and series resistance (Rs) of the Al/OG/p-Si diode were computed from the current-voltage (IV) measurements. Then, the n and ϕ b parameters were extracted as n = 2.65 ± 0.07 and ϕ b = 0.76 ± 0.05 eV from the IV results for the irradiated Al/OG/p-Si structure. It has been seen that these parameters were higher than those of the non-irradiated sample. In addition, it was observed that the rectification ratio of the diode decreased after irradiation, particularly in the wide voltage region. Moreover, the capacitance-voltage (CV) measurements showed that the capacitance values of the irradiated Al/OG/p-Si device increased, and the conductance (G) values in the inversion section for low frequencies increased because of the formation of electron-hole pairs or crystalline changes after irradiation. Furthermore, the irradiated and non-irradiated samples were evaluated by X-ray diffraction (XRD), and shifts in the diffraction angles and traces of microstructural changes were observed in the irradiated samples. Thus, it has been found that the radiation has remarkable effects on the dielectric parameters and the electronic and microstructural features of the Al/OG/p-Si structure.

Study on Electrophysical Properties in KMnO4-Doped Grade "Xorazm-150" Cotton Fibers

The main objective of the research was to identify the semiconducting characteristics of mature medium-thick (diameter 14, 15 µm) "Xorazm-150" cotton fibers both undoped and doped with 1.5% aqueous solution of KMnO4, including current versus voltage and temperature dependence, temperature dependence of electrical conductivity, the influence of doping time on conductivity, and photoconductivity. The research was conducted in the temperature range (296-360 K) and the voltage range (0-100 V). The infrared spectra of the undoped and KMnO4-doped samples were studied (Both samples were mercilized with NaOH). It was found that the cotton fibers sample doped with KMnO4 had considerably higher electrical conductivity than the undoped sample. It was determined that the cotton fibers sample doped with KMnO4 obeys the law of Ohm when current flows through it. Also, it was analyzed that the formation of photoconductivity of the cotton fibers sample doped with KMnO4 under the influence of ultraviolet radiation indicates that the photoconductivity is mainly related to the formation of band electron-hole pairs. The deep surface created by doping cotton fibers with a 1.5% solution of KMnO4 in water was found to have an activation energy that was determined from the results.

Synthesis of nanostructured gadolinium doped mixed ferrite: A novel catalyst for the mineralization of textile dyes

Herein, cobalt-nickel mixed ferrite (Co0·5Ni0·5Fe2O4, CNFO) and gadolinium doped cobalt-nickel mixed ferrite (Co0·5Ni0.5Gd0.1Fe1·9O4, G-CNFO) materials have been synthesized at the nanoscale via the microemulsion technique. The physicochemical features of the CNFO and G-CNFO materials were examined by advanced structural (PXRD and FTIR), morphological (FESEM), elemental (EDX), and optical (UV/Vis and transient photocurrent) studies. Under visible light, the catalytic activity of CNFO and G-CNFO materials was compared using Congo red and Aniline blue dyes as model textile pollutants. The G-CNFO material showed better photocatalytic activity than CNFO material, as it eliminated almost 21% more dye than CNFO material under the same experimental conditions. In order to find the optimal parameter for the experiments, the variables affecting the catalytic properties of the G-CNFO material were investigated in considerable detail. These variables included pH, catalyst dosage, dye concentration, temperature, and irradiation time. Scavenging and transient photocurrent experiments were also carried out in order to determine the key reactive oxygen species and the formation of electron-hole pairs. The G-CNFO mineralized the Congo red dye almost three times faster than its counterpart and showed a negligible loss in its catalytic activity even after five successive catalytic cycles. The combined effects of the G-CNFO material's tuned band structure, high light harvesting abilities, reduced electron-hole recombination, and nanostructured morphology resulted in its enhanced photocatalytic activity.

Photocatalytic Decomposition of Azo Dyes and Phenols Using Polymer Composites Containing Nanostructured Poly(Titanium Oxide) Doped with Gold or Silver Nanoparticles under Light Irradiation in a Wide Wavelength Range

The photocatalytic properties of poly(titanium oxide) (PTO) dispersed in optically transparent polymeric matrices of different natures under the action of both UV and visible light on aqueous solutions of azo dyes and phenols were investigated. PTO in materials forms clusters of mixed polymorphic modification—anatase and rutile—with an average size ~12 nm. With a one-electron transition Ti4+ + e− → Ti3+ accompanied by a reversible break of the Ti-O bond, the formation of electron-hole pairs and, consequently, active oxygen species occurs in PTO under UV irradiation. The PTO band gap in nanocomposites is 3.11–3.35 eV. Its doping with gold and silver nanoparticles with sizes from ~10 to ~30 nm reduces the PTO band gap by up to 2.11 eV, which leads to the operating wavelength range extension of the materials. It provides the enhancement of nanocomposites’ photocatalytic properties under UV irradiation and is the reason for their high activity under visible light action. It was found that azo dyes decompose by ~90% in this case. A phenol and para-nitrophenol conversion of 80–90% was proven at ~60 min upon their aqueous solutions’ visible-light irradiation at the nanocomposite concentration in a solution of 0.5 g/L.