Structural Properties Research Articles

Effect of Ga doping on the structural, optical, and electrical properties of ZnO nanopowders elaborated by sol-gel method

Nanostructured ZnO has received a considerable amount of interest, owing to its unique physical and chemical characteristics, as well as its remarkable performance in the fields of electronics, optics, and photonics. This work aims to study the influence of Ga dopant on the structural, optical, and electrical properties of ZnO nanopowders. Undoped and Ga-doped ZnO (GZO) nanopowders were successfully synthesised with the soft chemical sol-gel method. The solution was prepared using zinc acetate dihydrate and gallium (III) nitrate hydrate as precursors. The ethylene glycol is used as solvent. The X-ray diffractometer, scanning electronic microscope (SEM), UV–Vis, FTIR, and four-point probe method are used to analyse the properties of the synthesised powders. XRD and FTIR measurements show the growth of pure and Ga-doped ZnO crystals, which have a hexagonal wurtzite structure, and the average crystallite size varies from 9.09 nm to 24.8 nm. The nanospherical morphology of the nanopowders synthesised can be seen in the SEM images. The UV–visible spectroscopy shows that the optical gap energy increases with Ga concentration, from 3.59 eV to 3.67 eV. The I-V electrical measurements indicate that the breakdown voltage and the non-linear coefficient increase with Ga doping. This study will open the way for the investigation of a relationship between the electrical and nanostructural features of ZnO-based varistors for future device applications.

Fenugreek seed mucilage-based active edible films for extending fresh fruit shelf life: Antimicrobial and physicochemical properties

Trigonella foenum-graecum, known as fenugreek, belongs to the leguminous family of wild growth in Western Asia, Europe, the Mediterranean, and Asia; its ripe seeds contain a pool of bioactive substances with great potential in the food industry and medicine. In this study, fenugreek seed mucilage (FSM) was extracted and characterized in its structural properties by X-ray diffraction, nuclear magnetic resonance, and high-performance liquid chromatography. Then, the applicability of FSM as an antimicrobial agent was demonstrated via the development of novel, active, edible FSM-based biofilms containing carboxymethyl cellulose and rosemary essential oil (REO). Incorporating REO in the biofilms brought about specific changes in Fourier-transform infrared spectra, affecting thermal degradation behavior. Scanning electron microscopy and atomic force microscopy morphography showed an even distribution of REO and smoother surfaces in the loaded films. Besides, the solubility tests evidenced a reduction in water solubility with increasing REO concentration from 1 to 3 wt%. The biological assay evidenced the antimicrobial activity of REO-loaded biofilms against Staphylococcus aureus and Escherichia coli. Finally, whole apples were dip-coated with FSM-based solutions to showcase future edible systems. The REO-loaded biofilms extended the shelf life of apples to 30 days, demonstrating their potential for sustainable and active coatings.

Characterization Of Black Phosphorous Synthesized Via Ball-Milling Technique for The Effect of Milling Media and Time

Black phosphorus (BP), a unique arm-chair structure 2D material named for its distinctive black colour has been known to have intriguing properties include high energy storage and energy band-gap capabilities. BP is synthesized from the red phosphorus by using the ball-milling technique as an alternative to the existing complicated method which involves hazardous white phosphorus, high-temperature, and high-pressure conditions. Hence, we investigated and compared the effects of using alumina, stainless steel, and agate media on BP's physical and structural properties. The effects of milling time were performed afterward by using stainless-steel media for 1 h to 5 h. The ball-milling process at 450 rpm for 5 h in stainless steel media has transformed the coarse red powder into a dark black colour fine powder. The XRD analysis on the as-prepared powder revealed the existence of pure and crystalline black phosphorus. The Raman analysis indicated the apparent existence of BP structure synthesized. Observation of the FESEM images showed the BP existed with nanosized and flaky-shaped microstructure.

The Functional Role of Disordered Metal Oxides from Active Catalysis to Biological Metabolism

AbstractIt has been observed by many authors that highly active electrocatalysts are frequently “disordered” or “amorphous” in nature. The correlation between this lack of order and functionality is highly debated, with researchers still questioning if this structural property is a simple coincidence of the material preparation method, or if this lack of order has an important functional role for these catalysts. Using metal oxides as an example, how amorphous and disordered metal oxides can react by fundamentally different pathways are explored from more ordered forms with very similar bonding and redox states. The distinction between amorphous, disordered, and crystalline materials is reviewed in different characterization methods and suggests how these material characteristics fundamentally change the reactivity of these materials beyond surface area effects. How disorder can change the underlying thermodynamic stability of a material is explored, which in turn impacts redox potential, proton‐transfer, and electron‐transfer properties. It is these fundamental properties that govern the electrocatalytic activity and microbial metabolism of these materials. It is further argued that understanding the amorphous and disordered state of materials may be key to understanding a range of catalytic reactions; from clean energy reactions to the biological systems that underpin life's existence.

Adsorption dynamics of per- and polyfluoroalkyl substances (PFAS) on activated carbon: Interplay of surface chemistry and PFAS structural properties

Using activated carbon (AC) to adsorb per- and polyfluoroalkyl substances (PFAS) is highly practical for environmental remediation. However, examining the surface chemistry of carbonaceous material with regard to the removal of various PFAS has been limited, as the focus has often solely been on perfluorooctanoic acid and perfluorooctane sulfonic acid. Consequently, this study systematically explores the role of AC surface chemistry in the adsorption of PFAS with various structural properties using ACs that have been modified for different degrees of acidity, basicity, and hydrophobicity. Batch adsorption studies have demonstrated that the affinity of PFAS for the AC surface is negatively correlated with surface acidity. The removal performance at an adsorbent dose of 2 mg/L and an initial PFAS concentration of 600 ng/L is 27.4–91.4 %, 57.2–95.6 %, 92.4–99.2 %, and 89.1–99.6 % for an AC with an acidic surface, unmodified AC, defunctionalized AC, and AC with basic surface, respectively. Analyses of the adsorption isotherms, kinetics, and removal performance of the four types of ACs and 14 PFAS in water at different pH and ionic strengths reveal that hydrophobic, electron donor–acceptor, and electrostatic interactions, as well as negative charge-assisted hydrogen bond formation are necessary to describe the key adsorption characteristics observed in the experiments. The relative significance of the adsorption mechanisms depends on the PFAS structural properties, AC surface chemistry, and water composition. This extensive discourse contributes substantially to the design of an efficient carbonaceous adsorbent with specific surface moieties for removing PFAS from water.

Hot-Injection Synthesis of Cesium Lead Halide Perovskite Nanowires with Tunable Optical Properties

Metal halide perovskite semiconductors have emerged as promising materials for various optoelectronic applications due to their unique crystal structure and outstanding properties. Among different forms, perovskite nanowires (NWs) offer distinct advantages, including a high aspect ratio, superior crystallinity, excellent light absorption, and carrier transport properties, as well as unique anisotropic luminescence properties. Understanding the formation mechanism and structure–property relationship of perovskite NWs is crucial for exploring their potential in optoelectronic devices. In this study, we successfully synthesized all-inorganic halide perovskite NWs with high aspect ratios and an orthorhombic crystal phase using the hot-injection method with controlled reaction conditions and surface ligands. These NWs exhibit excellent optical and electrical properties. Moreover, precise control over the halogen composition through a simple anion exchange process enables the tuning of the bandgap, leading to fluorescence emission, covering a wide range of colors across the visible spectrum. Consequently, these perovskite NWs hold great potential for efficient energy conversion and catalytic applications in photoelectrocatalysis.

3D printing with a 3D printed digital material filament for programming functional gradients

Additive manufacturing, or 3D printing attracts growing attention as a promising method for creating functionally graded materials. Fused deposition modeling (FDM) is widely available, but due to its simple process, creating spatial gradation of diverse properties using FDM is challenging. Here, we present a 3D printed digital material filament that is structured towards 3D printing of functional gradients, utilizing only a readily available FDM printer and filaments. The DM filament consists of multiple base materials combined with specific concentrations and distributions, which are FDM printed. When the DM filament is supplied to the same printer, its constituent materials are homogeneously blended during extrusion, resulting in the desired properties in the final structure. This enables spatial programming of material properties in extreme variations, including mechanical strength, electrical conductivity, and color, which are otherwise impossible to achieve with traditional FDMs. Our approach can be readily adopted to any standard FDM printer, enabling low-cost production of functional gradients.

Electronic Properties of DNA Origami Nanostructures Revealed by In Silico Calculations.

DNA origami is a pioneering approach for producing complex 2- or 3-D shapes for use in molecular electronics due to its inherent self-assembly and programmability properties. The electronic properties of DNA origami structures are not yet fully understood, limiting the potential applications. Here, we conduct a theoretical study with a combination of molecular dynamics, first-principles, and charge transmission calculations. We use four separate single strand DNAs, each having 8 bases (4 × G4C4 and 4 × A4T4), to form two different DNA nanostructures, each having two helices bundled together with one crossover. We also generated double-stranded DNAs to compare electronic properties to decipher the effects of crossovers and bundle formations. We demonstrate that density of states and band gap of DNA origami depend on its sequence and structure. The crossover regions could reduce the conductance due to a lack of available states near the HOMO level. Furthermore, we reveal that, despite having the same sequence, the two helices in the DNA origami structure could exhibit different electronic properties, and electrode position can affect the resulting conductance values. Our study provides better understanding of the electronic properties of DNA origamis and enables us to tune these properties for electronic applications such as nanowires, switches, and logic gates.

Free-standing ultrathin silicon wafers and solar cells through edges reinforcement

Crystalline silicon solar cells with regular rigidity characteristics dominate the photovoltaic market, while lightweight and flexible thin crystalline silicon solar cells with significant market potential have not yet been widely developed. This is mainly caused by the brittleness of silicon wafers and the lack of a solution that can well address the high breakage rate during thin solar cells fabrication. Here, we present a thin silicon with reinforced ring (TSRR) structure, which is successfully used to prepare free-standing 4.7-μm 4-inch silicon wafers. Experiments and simulations of mechanical properties for both TSRR and conventional thin silicon structures confirm the supporting role of reinforced ring, which can share stress throughout the solar cell preparation and thus suppressing breakage rate. Furthermore, with the help of TSRR structure, an efficiency of 20.33% (certified 20.05%) is achieved on 28-μm silicon solar cell with a breakage rate of ~0%. Combining the simulations of optoelectrical properties for TSRR solar cell, the results indicate high efficiency can be realized by TSRR structure with a suitable width of the ring. Finally, we prepare 50 ~ 60-μm textured 182 × 182 mm2 TSRR wafers and perform key manufacturing processes, confirming the industrial compatibility of the TSRR method.

Structural, Morphological and Optical and Electrical Properties of Ba0.4Cu0.6-xLaxTiO3 (x = 0.2, 0.4, 0.6) Nanoparticles

the structural, morphological, optical and electrical properties of Ba0.4Cu0.6-xLaxTiO3 (x = 0.2, 0.4, 0.6) nanoparticles are discussed. It begins with the preparation followed by characterization of the materials. The sample material is synthesized by hydrothermal technique and then the structure of the present sample is confirmed by diffraction pattern and compared with the respective standard JCPDS pattern. In addition, the structural parameters such as the lattice constant (a), average crystallite size (Dp), theoretical density (ρx), porosity (P), dislocation density (ρd) and strain (ε) are evaluated. In this study, morphology is analyzed using the SEM and TEM measurements. The optical properties such as A, B-site wave numbers, force constants and optical band gap energies (Eop) are studied by FTIR and UV-Visible spectrometers respectively. Electric and dielectric properties have been studied over a frequency range of 100 Hz – 1 MHz and in the temperature range from 40oC to 100oC.

Structural and mechanical properties of monolayer amorphous carbon and boron nitride

Structural and mechanical properties of monolayer amorphous carbon and boron nitride

Growth of L asparagine monohydrate doped potassium dihydrogen phosphate semiorganic crystals and its structural, thermal and optical properties

A novel semiorganic crystal is harvested by doping organic amino acid L asparagine monohydrate (LAM) with inorganic compound Potassium dihydrogen phosphate (KDP) by adopting slow evaporation method. Rietveld refinement of the XRD data was performed and the structural study exhibits single phase nature of the LAM doped KDP (LAM-KDP) crystals with a slight decrease in c-axis of the unit cell parameters. Other crystallographic parameters such as crystallite size and strain were also evaluated. The interaction of LAM with KDP was studied from FT-IR analysis by detecting functional groups. The constituting elements of the crystal were identified by energy dispersive X-ray (EDX) analysis. Etching study has been employed to study surface morphology of these crystals. From UV–vis transmittance data, optical band gap and different optical constants like Urbach energy, dielectric constants, electrical and optical conductivities were evaluated. Optical transparency of the LAM-KDP crystals is observed to increase. The third order nonlinear susceptibility χ(3) and nonlinear refractive index n2 of the grown crystals have been predicted using empirical Miller's rule. The value of χ(3) has increased from 1.87 × 10−13 esu to 4.29 × 10−13 esu due to LAM doping. Change in enthalpy (ΔH), change in Gibb's free energy (ΔG) and activation energy Ea during chemical reaction were calculated by thermogravimetric analysis (TGA). Thermal decomposition characteristics of the crystals were analyzed by differential scanning calorimetry (DSC). The high transparency of LAM-KDP crystals in the entire visible spectrum and larger values of nonlinear susceptibility χ(3) and nonlinear refractive index n2 make the synthesized crystal applicable for NLO and optoelectronic devices applications.

Investigation of the Influence of Alloy Atomic Doping on the Properties of Cu-Sn Alloys Based on First Principles

In order to design Cu-Sn alloys with excellent overall performance, the structural stability, mechanical properties, and electronic structure of X-doped Cu-Sn alloys were systematically calculated using first-principles calculations. The calculation results of the cohesive energy indicate that the Cu-Sn-X structures formed by X atoms (X = Ag, Ca, Cd, Mg, Ni, Zr) doping into Cu-Sn can stably exist. The Cu-Sn-Ni structure is the most stable, with a cohesive energy value of −3.84 eV. Doping of X atoms leads to a decrease in the bulk modulus, Possion’s ratio and B/G ratio. However, doping Ag and Ni atoms can improve the shear modulus, Young’s modulus, and strain energy of the dislocation. The doping of Ni has the highest enhancement on shear modulus, Young’s modulus, and strain energy of the dislocation, with respective values as follows: 63.085 GPa, 163.593 GPa, and 1.689 W/J·m−1. The analysis of electronic structure results shows that the covalent bond between Cu and X is the reason for the performance differences in Cu-Sn-X structures.

Sustainable and efficient oil-water separation using bio tin oxide-based superhydrophobic membrane

IntroductionSuperhydrophobic materials are considered an ideal method for oil-water separation. However, existing oil-water separation methods have the problem of manufacturing complex and toxic chemical reagents. To address the limitation, we proposed a novel approach to sustainable and efficient oil-water separation using a superhydrophobic membrane based on the Bio Tin oxide nanoparticles (Bio-SnO2 NPs).MethodsThe study involves synthesizing Bio-SnO2 NPs from the sunflower leaf extract which was natural and non-toxic and modifying textile fabric with a superhydrophobic coating (S.T.F.). Characterization techniques including SEM, FTIR, and BET analysis are employed to assess the structural and textural properties of the modified membrane.Results and DiscussionThe textile fabric was modified with a superhydrophobic coating (S.T.F.), demonstrating enhanced wettability, oil absorption capacity, and oil-water separation performance. The Bio-SnO2 NPs exhibited crystalline structures with a length of 90 nm and a diameter of 20 nm, as confirmed by SEM analysis. FTIR results revealed characteristic peaks at 3410 cm-1 and 642 cm-1, indicating the presence of hydroxyl group and Sn-O bonds confirming the successful synthesis of Bio-SnO2 NPs. BET analysis showed a substantial specific surface area of 413 m2/g and a pore volume of 0.19 cm3/g, emphasizing the textural properties. The FTIR and SEM techniques were used to study the characteristics of the textile fabric before and after modification with the superhydrophobic coat. The S.T.F. exhibited remarkable superhydrophobicity with a water contact angle of 152° and a water sliding angle of 4°. Absorption capacities for coconut oil, diesel, and hexane were found to be 70.4 g/g, 63.5 g/g, and 49.6 g/g, respectively, with excellent cyclic stability. Separation efficiency for hexane, diesel, and coconut oil was found to be 99.5, 97.1%, and 96.3%, respectively, with excellent cyclic stability. Mechanical stability test revealed superhydrophobicity retention even after an abrasion length of 200 mm. The chemical stability test indicated that the superhydrophobicity was maintained in the pH range of 3-11. Moreover, the flux for hexane, diesel, and coconut oil was 9400 L m−2 h−1, 8800 L m−2 h−1, and 8100 L m−2 h−1, respectively, highlighting the membrane’s efficient oil-water separation capabilities. These results collectively position the developed S.T.F. as a promising and sustainable solution for diverse oil-water separation applications.

First-principles Investigations of Structural, Thermodynamic, Optoelectronic and Thermoelectric Properties of Rb2CuMF6 (M = As3+, Bi3+) Eco-friendly Halide Double Perovskites: Materials for Green Energy Applications

First-principles Investigations of Structural, Thermodynamic, Optoelectronic and Thermoelectric Properties of Rb2CuMF6 (M = As3+, Bi3+) Eco-friendly Halide Double Perovskites: Materials for Green Energy Applications

An Enhanced Optical Response and Interfacial Charge Separation Of rGO Supported Cu2+ Doped Co3O4 Heterojunction For Photo‐Fenton‐Like Activity

AbstractIn recent years, clean water and increasing the usage of renewable energy have been the two main goals to be focused on in developing a sustainable living environment. These goals can also be fulfilled by using photocatalytic processes which is a promising direction, photocatalyst is quite effective for water purification and sustainable energy resources. For the first time, we report a visible‐light‐driven photocatalyst of rGO/Cu−Co3O4 nanocomposite for photo‐Fenton‐like degradation activity. The structural, morphological, surface chemical and optical properties of the samples were deeply analysed. The Cu2+ replacement reduces the crystalline size of the Co3O4 nanoparticle and rGO addition enhances the active surface area and charge mobility towards the better catalytic activity. The effect of operating parameters such as pH, catalyst dose, dye concentration, and H2O2 was also investigated for methylene blue (MB) dye degradation: kinetic studies, active radicals finding, and percentage of total organic carbon removal were also discussed in detail.

Deposition time dependent structural and optical properties of polycrystalline [formula omitted] films

Sputtering-derived InGaZnO4 (IGZO) thin films were grown on quartz substrates and undergone post-deposition annealing at 700 °C for 2hr in N2 ambient. The influence of deposition time or film thickness on the morphological, structural and optical properties of polycrystalline IGZO thin films has been systematically investigated by means of characterization from field-emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), high resolution X-ray diffraction (HRXRD) and ultraviolet–visible–near infrared (UV–Vis–NIR) spectrophotometer. Results of AFM have shown that the root-mean-square (RMS) surface roughness of the IGZO films increases from 0.888 to 2.640 nm as the deposition time is extended from 50 to 250min. Analysis of XRD indicates that all the films are in polycrystalline phase, with crystallites growing into larger size accordingly to increasing deposition time. Appealingly and scarcely ever reported, the XRD diffraction planes can be separated into three domains, such as (0 0 l), (1 0 l) and (1 1 l) with different growth thicknesses. Optical measurement suggests that the optical bandgap have redshifted from 3.55 to 3.31eV at longer deposition time. Related mechanics about the change in physical properties against deposition time have been elaborated in detail. The validity of Swanepoel method, 1983 in deriving the refractive index of thick IGZO films has also been discussed.

Effect of Triton X-100 surfactant on structural, morphological, and optical properties of ZnS thin films deposited by spin coating method

Effect of Triton X-100 surfactant on structural, morphological, and optical properties of ZnS thin films deposited by spin coating method

The Optimal Doping Ratio of Fe2O3 for Enhancing the Electrochemical Stability of Zeolitic Imidazolate Framework-8 for Energy Storage Devices

This paper aims to discover a novel composite material that has great potential for manufacturing high-performance supercapacitors suitable for diverse applications, such as electric vehicles, portable electronics, and stationary energy storage systems. Zeolitic imidazolate framework-8 (ZIF-8) doped by different concentrations up to 5 wt.% of nanosized Fe2O3 have been prepared (ZIF-8/Fe2O3). The effect of doping ratio 1, 3, and 5 wt.% on the structural and electrochemical properties of ZIF-8/Fe2O3 has been investigated. The structural characterization has been carried out using TGA, BET, XRD, and FTIR. The XRD analysis revealed that the crystalline size of our sample increased by approximately 16% as a result of doping ZIF-8 with 5 wt.% of Fe2O3. The structural analysis of the doped samples revealed that the material exhibited enhanced thermal stability and porosity, with an increase of approximately 105 m2/g. The introduction of doped nanometal oxides improved the capacitance value of ZIF-8 by significantly increasing its surface area. Additionally, the electron transport efficiency within ZIF-8/5 wt.% Fe2O3/electrode is increased. The Nyquist plot decreases as the doping of Fe2O3 increases. This indicates a decrease in the charge transfer resistance at the electrode–electrolyte interface, which is desired in applications such as batteries, fuel cells, or electrochemical sensors where faster electron transfer is needed for improved performance.

Synthesis‐structure‐catalysis relations in CHA zeolites applied for selective catalytic reduction of NOx with ammonia

Microporous aluminosilicate zeolites are useful industrial catalysts. However, their hydrothermal synthesis is a multistep process with complicated and unclear reactions, limiting their rational functional design. Herein, we compare the formation pathway and the structural and catalytic properties of several CHA zeolites to obtain fundamental knowledge for intentionally controlling the catalytic function of zeolites. Three CHA zeolites were synthesized using different starting silica/alumina sources in the presence of tetraethylammonium hydroxide as an inexpensive organic structure‐directing agent. FAU zeolite and an amorphous synthesis gel prepared using two different methods were used as starting materials. The obtained CHA zeolites were applied for exhaust gas purification (selective catalytic reduction of NOx with ammonia, NH3‐SCR), and their structural characteristics and formation pathways were investigated using a combination of analytical methods. Stepwise gel preparation (SGP), which divides the compositional control of the amorphous synthesis gel, promotes the decomposition of the initial additive (zeolite seed), resulting in the formation of CHA zeolites with abundant micropores and paired Al sites. This structural feature obtained using the SGP method improves the catalytic durability of the NH3‐SCR reaction. The present relationship, including different crystallization phenomena, structures, and catalytic abilities, provides useful insights into rational zeolite synthesis and its application.