Raman Spectroscopy Research Articles

Isolation of seawater microplastics from biologically rich samples using an alkaline K2S2O8 method

In recent years, microplastics, especially marine microplastic pollution, have received global attention as a new type of environmental problem. The establishment of accurate and efficient methods for the detection of microplastics is the basis for in-depth research on the transport, transformation, fate, and ecotoxicological effects of microplastics in the environment. Microplastics in seawater frequently mix with biological tissues, resulting in challenges when identifying samples. However, commonly used pretreatment protocols for microplastics often suffer from long digestion times, inadequate digestion, and the risk of potentially damaging microplastics. This study compared the digestion efficiencies of five digestion reagents and provided further insights into two advanced oxidation methods involving Fenton’s reagent and an innovative alkaline K2S2O8 protocol based on sulfate and hydroxyl radicals. Using Raman spectroscopy, scanning electron microscopy-energy dispersive spectroscopy (SEM−EDS), and carbonyl index (CI) analyses, the status of microplastics after pretreatment was evaluated. The results revealed that the alkaline K2S2O8 method could enhance the reaction efficiency while reducing the potential for functional group damage during microplastic pretreatment. Moreover, the proposed K2S2O8 method was applied to the pretreatment of field seawater samples, and field microplastics were effectively separated from biologically rich samples. Thus, a digestion protocol based on alkaline K2S2O8 provides an effective way to isolate seawater microplastics from biologically rich samples. This study contributes to the development of efficiently microplastic monitoring and provides valuable insights into access to reliable data for fate and inventory of oceanic microplastics.

Mitigating infections in implantable urological continence devices: risks, challenges, solutions, and future innovations. A comprehensive literature review.

Stress urinary incontinence is a growing issue in ageing men, often following treatment for prostate cancer or bladder outflow obstruction. While implantable urological devices offer relief, infections are a significant concern. These infections can lead to device removal, negating the benefits and impacting patient outcomes. This review explores the risks and factors contributing to these infections and existing strategies to minimize them. These strategies encompass a multifaceted approach that considers patient-specific issues, environmental issues, device design and surgical techniques. However, despite these interventions, there is still a pressing need for further advancements in device infection prevention. Faster diagnostics, such as Raman spectroscopy, could enable early detection of infections. Additionally, biocompatible adjuncts like ultrasound-responsive microbubbles hold promise for enhanced drug delivery and biofilm disruption, particularly important as antibiotic resistance rises worldwide. By combining advancements in diagnostics, device design, and patient-specific surgical techniques, we can create a future where implantable urological devices offer men a significant improvement in quality of life with minimal infection risk.

Degradation of dye through mechano-catalysis using BaBi4Ti4O15 catalyst

Ferroelectric BaBi4Ti4O15 was prepared using solid-state calcination at 950 °C for four hours. X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy were utilized to understand its microstructure and other structural aspects. Particle size was around < 1.5 µm. This oxide is able to demonstrate piezocatalysis and tribocatalysis as reflected in its dye degradation performance. This oxide showed piezocatalytic activity around 40% in 2 h and tribocatalytic activity around 90% in 12 h. The rate constant for the piezocatalytic reaction is 0.003 min−1 and for tribocatalytic reaction is 0.169 h−1. The rotation speed also affected the tribocatalytic activity of the oxide. Oxide showed 25%, 90%, and 94% tribocatalytic activity at 300, 500, and 700 rpm respectively. This material has demonstrated notable performance of catalysis under different types of mechanical energy sources and under different mechanisms.

Electric-Field-Driven Localization of Molecular Nanowires in Wafer-Scale Nanogap Electrodes.

As integrated circuits continue to scale toward the atomic limit, bottom-up processes, such as epitaxial growth, have come to feature prominently in their fabrication. At the same time, chemistry has developed highly tunable molecular semiconductors that can perform the functions of ultimately scaled circuit components. Hybrid techniques that integrate programmable structures comprising molecular components into devices however are sorely lacking. Here we demonstrate a wafer-scale process that directs the localization of a conductive polymer, Mw = 20 kg mol-1 polyaniline, from dilute solutions into 50 nm vertical nanogap device architectures using electric-field-driven self-assembly. The resulting metal-polymer-metal junctions were characterized by electron microscopy, Raman spectroscopy and transport measurements demonstrating that our technique is highly selective, assembling conductive polymers only in electrically activated nanogaps. Our results represent a step toward scalable hybrid nanoelectronics that seamlessly integrate established lithographic top-down fabrication with bottom-up synthesized molecular functional circuit components.

Interphase-Controlled Inkjet Printing of MicroInlaid OLEDs: Effects of Solvent- and Solute-Polymer Interactions.

Inkjet printing, a highly promising technique for the cost-effective fabrication of large-scale organic light-emitting devices (OLEDs), typically necessitates the intricate alignment of precisely patterned insulating layers. Recently, we introduced a unique single-step inkjet printing process that produces well-patterned microinlaid spots of functional compounds through insulating polymer layers. This approach exploits lateral phase separation between the solute of functional compounds and the polymer, allowing the simultaneous spatial etching of the polymer and the infilling of the solute using a single inkjet-printed sessile droplet. Here, we demonstrate that the interaction between the solvent and polymer, as well as the solute and polymer, critically determines the precision and efficiency of printing. This is particularly evident when using either the insulating poly(vinylpyridine) isomer of poly(4-vinylpyridine) (P4VP) or poly(2-vinylpyridine) (P2VP) with chloroform as a solvent, which allows for a detailed examination of these interactions based on certain solubility parameters. Micro-Raman spectroscopy reveals that the self-organizing capability of the microinlaid spots with P4VP is superior to that with P2VP. This is due to the fact that P2VP shows higher affinity to the solvent and causes imperfect phase separation as compared to P4VP. As a result, a performance evaluation demonstrates enhanced device performance for inkjet-printed green micro-OLEDs with P4VP, exhibiting a higher external quantum efficiency of 3.3% compared to that of 2.3% achieved with P2VP. These findings elucidate the important roles of solvent-polymer and solute-polymer interactions in the inkjet printing process, leading to interfacial control of inkjet printing technique for the cost-effective production of high-performance and high-resolution micro-OLEDs.

Visualization of Electrooxidation on Palladium Single Crystal Surfaces via In Situ Raman Spectroscopy.

The electrooxidation of catalyst surfaces is across various electrocatalytic reactions, directly impacting their activity, stability and selectivity. Precisely characterizing the electrooxidation on well-defined surfaces is essential to understanding electrocatalytic reactions comprehensively. Herein, we employed in situ Raman spectroscopy to monitor the electrooxidation process of palladium single crystal. Our findings reveal that the Pd surface's initial electrooxidation process involves forming *OH intermediate and ClO4- ions facilitate the deprotonation process, leading to the formation of PdOx. Subsequently, under deep electrooxidation potential range, the oxygen atoms within PdOx contribute to creating surface-bound peroxide species, ultimately resulting in oxygen generation. The adsorption strength of *OH and the coverage of ClO4- can be adjusted by the controllable electronic effect, resulting in different oxidation rates. This study offers valuable insights into elucidating the electrooxidation mechanisms underlying a range of electrocatalytic reactions, thereby contributing to the rational design of catalysts.

Efficient Charge Transfer in Graphene/CrOCl Heterostructures by van der Waals Interfacial Coupling.

Due to the large volume of exposed atoms and electrons at the surface of two-dimensional materials, interfacial charge coupling has been proven as an efficient strategy to engineer the electronic structures of two-dimensional materials assembled in van der Waals heterostructures. Recently, heterostructures formed by graphene stacked with CrOCl have demonstrated intriguing quantum states, including a distorted quantum Hall phase in the monolayer graphene and the unconventional correlated insulator in the bilayer graphene. Yet, the understanding of the interlayer charge coupling in the heterostructure remains challenging. Here, we demonstrate clear evidences of efficient hole doping in the interfacial-coupled graphene/CrOCl heterostructure by detailed Raman spectroscopy and electrical transport measurements. The observation of significant blue shifts and stiffness of graphene Raman modes quantitatively determines the concentration of hole injection of about 1.2 × 1013 cm-2 from CrOCl to graphene, which is highly consistent with the enhanced conductivity of graphene. First-principles calculations based on density functional theory reveal that due to the large work function difference and the electronegativity of Cl atoms in CrOCl, the electrons are efficiently transferred from graphene to CrOCl, leading to hole doping in graphene. Our findings provide clues for understanding the exotic physical properties of graphene/CrOCl heterostructures, paving the way for further engineering of quantum electronic states by efficient interfacial charge coupling in van der Waals heterostructures.

Studying on the in vivo pathological evolution of spinal cord injury with the rat model by the method of integrated multispectral imaging and Raman spectroscopy

Spinal cord injury (SCI) is a debilitating neurological and pathological condition that results in significant impairments in motor, sensory, and autonomic functions. By integrating multispectral imaging (MSI) with Raman spectroscopy, a label-free optical methodology was developed for achieving a non-invasive in vivo understanding on the pathological features of SCI evolution. Under the guidance of captured the spectral imaging data cube with a rigid endoscope based MSI system, a special designed fiber probe passed through the instrumental channel for acquiring the finger-print spectral information from compression rat SCI models. After identifying the main visual features of injured spinal cord tissue in all Sham, 0-, 3- and 7-days post injury (0 DPI, 3 DPI, and 7 DPI) groups, the blood volume and oxygen content were visualized to describe hemorrhage, hypoxia and inflammatory state after acute injury. The averaged reflectance spectra, which were deduced from MSI data cubes, were utilized for describing oxygen saturation and hemoglobin concentration in living tissue. The results of Raman spectroscopy addressed complex compositional and conformational phenomena during SCI progression, correlated with the well-known event like neuronal apoptosis, hemorrhage, demyelination, and even the upregulation of chondroitin sulfate proteoglycans (CSPGs). A principal component analysis and linear discriminate algorithm (PCA-LDA) based discriminate model was introduced for categorizing spectral features in different injury stages, which was applicable for intraoperative interpretations on the complex pathological courses of SCI and therapeutic outcomes.

Structural and biophysical insights into the interactions of anisotropic gold nanoparticles with human telomeric G-quadruplex DNA: Spectroscopic and calorimetric approach

We are reporting curcumin-induced synthesis of anisotropic citrate capped Gold nanoparticles (ctGNPs). The techniques such as UV–visible spectroscopy, Raman spectroscopy, FT-IR, X-ray diffraction (XRD), and Transmission Electron Microscopy (TEM) were used to characterize the nanoparticles. The synthetic route shows the formation of an anisotropic gold nanostructure consisting of spherical, triangles, hexagonals, and a low-yield rod with an aspect ratio ranging from 4.2 to 8.5. Curcumin-derived ctGNPs shows stability at different physiological conditions and better biocompatibility. Synthesized nanoparticles are found non-toxic towards eukaryotic cells but more effective against the cancer cell lines HeLa and MCF-7. The interaction of these synthesized nanoparticles with human telomeric G-quadruplex (GQ) DNA was studied using different physiochemical methods. The spectroscopic studies show that synthesized nanoparticles have stronger binding affinity towards telomeric GQ as compared to ds DNA through Van der Waals and H-bonding interactions. Thermodynamic interpretation reveals that the formation of the complex between the telomeric GQ and ctGNPs are enthalpy driven and entropy unfavourable process, resulting in motion freezing and, eventually, AuNP aggregation. Thus, our study shows a new approach to understand the interaction of telomeric G-quadruplexes with gold nanoparticles generated via the green route.

Catalytic particles formation from thin nickel films for the synthesis of multi-walled carbon nanotubes

We have investigated the formation of a catalyst for the synthesis of multi-walled carbon nanotubes (MWCNT) using nickel-on-titanium thin films. Nickel decomposes into nanoparticles in the synthesis setup prior to MWCNT growing through the plasma enhanced chemical vapor deposition method. Oxidation and reduction of the catalyst are conducted to control the morphology of the formed nanoparticles array. In this case, the redox treatments required preventing the formation of silicides and Ti–Ni alloys are combined with the well-known effect of low-temperature disintegration (dewetting) of thin films. Detailed studies using a combination of Auger, atomic force, scanning (SEM), and transmission electron microscopy (TEM) show the interaction of metals on a silicon substrate, the influence of treatments parameters on the catalyst's state. The features and morphology of MWCNT synthesized on the obtained catalysts were studied via Raman spectroscopy, SEM and TEM. Overall, showing a link between the catalyst formation process and MWCNT growth, we demonstrate a technological and versatile method for controlling of nanotube growth for various applications.

Wafer-scale Te thin film with high hole mobility and piezoelectric coefficients

p-type semiconductors are significant for integrated nanoelectronics. Tellurium (Te), a mono-elemental material, is a p-type semiconductor with high mobility. Its outstanding performance renders it widely applicable in the fields of electronics and optoelectronics. However, the wafer-scale fabrication of Te thin films is challenging. In this study, we reported an ion-bean sputtered Te thin film and investigated the effects of annealing temperatures. Annealing-induced crystallization kinetics were assessed through Raman spectroscopy, x-ray diffraction, and atomic force microscopy. After annealing, the film's conductivity increased from 10−5 to 10−4 S and mobility from 18 to 53 cm2 V−1 s−1. Dual AC resonance tracking switching spectroscopy piezoelectric force microscopy is used to investigate piezo/ferroelectric properties. The coercive voltages are −2 and 4 V respectively, and the effective piezoelectric coefficient (d33) is 40 pm/V. Butterfly and phase-switching loops demonstrate its possible ferroelectricity. The Te thin film has potential applications in optoelectronics, nonvolatile memory devices, and neuromorphic computation.

Synthesis Method Comparison of N-Doped Carbons for Electrochemical Energy Storage

This study investigates nitrogen-doped carbon synthesis and electrochemical properties as electrode material for energy storage devices, an additional focus of the work is on the electrochemical exfoliation synthesis of nitrogen-doped carbon using various precursors and doping methods. The physical properties of the synthesized sample are characterized using X-ray photoelectron spectroscopy, scanning electron microscopy, and Raman spectroscopy. The electrochemical properties of the N-doped carbons are studied using cyclic voltammetry and galvanostatic charge-discharge cycling. Finally, the work explores the potential application of the N-doped carbons as electrode material for energy storage devices, such as supercapacitors. The results show that N-doped carbons exhibit electrochemical performance superior to that of graphene oxide, with higher electrical capacitance. The results demonstrate the potential of N-doped carbons as high-performance electrode materials for electrochemical energy storage applications. This paper aims to explain the advantages of N-doping in carbon materials more precisely in graphene and the use of these materials in creating electrodes for application in supercapacitors and batteries.

Fabrication, structural, morphological, and mechanical behaviour of fly ash doped clay ceramics based CO2 gas sensor

Various attempts have been made to fabricate fly ash-doped clay composites via solid state reaction method. Additionally, to investigate the structural, mechanical, surface morphology, and CO2 gas sensing behavior, the fabricated clay composites were sintered at three different temperatures 1000, 1100, and 1200 °C (COF1, COF2, COF3) for 4 h. The green and sintered densities of the fabricated composites were found to be in the range of 2.17–2.13 g cm−3 and 1.38 to 1.30 g cm−3. Further, various characterization techniques such as x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, universal testing machine (UTM) and scanning electron microscopy (SEM) with energy-dispersive x-ray spectroscopy (EDAX) were carried out. Moreover, to determine the compressive strength and Young’s modulus values, a universal testing machine (UTM) was used. The fracture toughness of the fabricated composites, COF2 and COF3 were found to be 7.84 MPa-m1/2 and 2.22 MPa-m1/2. The COF3 composite exhibited a sensing response, response time, recovery time of 3.39 at 1200 ppm CO2, 16.95 s and 18.05 s respectively. Consequently, this porous clay composite can be fabricated in a cost-effective and eco-friendly manner, hence beneficial for CO2 gas sensing applications.

The oxygen vacancies induced local surface plasmon resonance for NIR shielding in titanium-tungsten oxide doped borosilicate glasses

The global energy demand is going to increase manifold in coming years. To meet future energy requirements, we need to save energy by all the means. The main perspective of the present work is to synthesize cost-effective borosilicate glasses which were synthesised for NIR-shielding application. NIR shielding energy saving glass system was prepared by conventional melt quenching method. The chosen chemical composition is xWO3+(27−x)Na2O+38.7B2O3+34SiO2+0.3TiO2 (where x= 0, 1, 2, 3, 4 and 5 mol%). The X-ray diffraction (XRD), UV–Vis-NIR and Raman spectroscopy were employed to evaluate the structural and optical properties of titanium-tungsten oxide doped borosilicate glasses, respectively. X-Ray Photoelectron spectroscopy (XPS) confirmed the chemical states of the tungsten in the glasses. The glass having x=3 mol% of WO3 and 0.3 mol% of TiO2 borosilicate glass (BSG 3) is found to have good NIR shielding ability (Tmin ∼ 77.3 % at 2217 nm) with acceptable visible light transmittance (Tmax ∼ 90.4 % at 772 nm), and hence proposed for applications in NIR-shielding energy-saving windows. The present study emphasizes on tunable NIR-shielding performance of synthesised energy-saving glasses. The optimized glass composition can be taken from lab to industrial application and many more endeavors for the manufacturing of energy saving glasses. The glass having x=3 mol% of WO3 and 0.3 mol% of TiO2 borosilicate glass (BSG 3) is found to have good NIR shielding ability (Tmin ∼ 77.3 % at 2217 nm) is attributed to titanium-tungsten oxide incorporation in glass network. The energy saving glasses, transparent to visible light and having NIR shielding, can be used in glass windows of industry buildings, houses and motor vehicles to reduce the load on air conditioners.

Influence of Mg+2 on the structure, microstructure, and magnetic interactions of zinc ferrite nanoparticles synthesized via co-precipitation route

Evolution of the structural, morphological and magnetic properties of Zn1-xMgxFe2O4 (X = 0.00, 0.10 and 0.20) nanoparticles are discussed in detail and relation between cation disorder and magnetic interactions are prospected. The synthesized samples sintered at 500 °C temperature under examination display cubic crystal structure possesses Fd-3m as space group. The average crystallite size and lattice parameter shows variation as revealed from scherrer equation with the addition of Mg dopant at zinc site. Rietveld refinement presented single phase formation. Raman spectroscopy was utilized to convey different Raman modes and their associated vibrations. Scanning electron microscopy was utilized to survey the morphological attributes. Magnetization studies reveal weak ferromagnetism at low temperature (5 K) due to cation disorder for all samples. Zero field cooled and field cooled curves from magnetization vs temperature reveal the blocking temperature and its dependence on cation disorder and particle size. These results provide information about the possible applications of zinc ferrite nanoparticles in magnetic sensors, nanomedicine, optoelectronics, and memory devices.

Polyelectrolyte mixture enables electrowetting liquid lens with large optical power tuning range

Electrowetting liquid lenses have aroused considerable interest among researchers in a variety of industrial applications and wetting sciences. However, conventional electrowetting liquid lenses face significant limitations in their optical power tuning range due to contact angle saturation. To address this issue, our research introduces a polyelectrolyte mixture (PM) composed of ammonium polyphosphate and potassium chloride, which enables a broad optical power tuning range for electrowetting liquid lenses. Through a comprehensive analysis involving viscosity, Raman spectrum, and contact angle measurements, we offer additional insights into the interdisciplinary mechanism of the PM in enhancing the electrowetting effect. Our investigation elucidates how the conformation of the polyelectrolyte and the formation of hydrogen bonds at varying concentrations can impact the electrowetting gain. By optimizing the electrowetting concentration of the PM (12.5 wt. % ammonium polyphosphate and 7.5 wt. % potassium chloride), we achieve a liquid lens with an extensive tuning range (−37.97 to +18.71 D) at 0–45 V, featuring a substantial aperture (6.4 mm) and a low threshold voltage (10 V). This PM formulation effectively mitigates contact angle saturation, thereby offering promising applications and paving the way for the development of liquid lenses with a significantly enhanced optical power tuning capacity.

Co-melting mechanisms for municipal solid waste incineration fly ash with fine slag from coal gasification and coal gangue

Vitrification is a promising treatment for municipal solid waste incineration fly ash (MSWI-FA); however, high energy consumption due to the high MSWI-FA fusion temperature limits the development and application of this technique. In this study, fine slag ash (FSA) derived from coal gasification and coal gangue ash (CGA) were mixed with MSWI-FA to reduce the ash fusion temperature. The transformation of minerals in ash during thermal treatment was examined via X-ray diffraction and thermodynamic equilibrium calculations. The ash flow behaviour was observed using a thermal platform microscope, and the silicate structure was quantified using Raman spectra. The co-melting mechanisms for the mixed ash were systematically investigated. Results indicate that the flow temperature (FT) of the mixed ash exhibited an initial decrease and subsequent increase as a function of the addition ratio of FSA or CGA. Lowest ash FT of 1215 °C and 1223 °C were recorded for addition of 50% FSA and 50% CGA, respectively; further, these temperatures were lowered by > 285 °C and >277 °C respectively, relative to FT of the MSWI-FA. The transformation of minerals and silicate structure during mixed ash heating was responsible for the variation in the ash fusion temperature. CaO in MSWI-FA tended to react with mullite, quartz and haematite in FSA and CGA, forming minerals such as anorthite, gehlenite, and andradite with relatively low melting points. The addition of FSA or CGA caused changes in the silicate network structure of the mixed ash. In particular, 50% FSA incorporation caused the transformation of Q4 and Q3 to Q2, whereas 50% CGA introduction resulted in the conversion of Q4 and Q2 into Q3 and Q1 + Q0, respectively. The silicate network depolymerised, causing reduction in the ash fusion temperature and increasing the melting rate.

Biosynthesis of microrubble-shaped nanoporous Co3O4/rGO NCs using leaves extract of Neolamarckia cadamba and its antibacterial/antioxidant performance

Nowadays, the whole globe is paying great attention for the sustainable development, eco-friendly and economical production of nanostructures materials. With this motivation, the present work portrayed one-step ‘in-situ’ bioinspired green fabrication of Co3O4–reduced graphene oxide nanocomposites (Co3O4–rGO NCs) for the first time utilizing an aqueous leaf extract of Neolamarckia cadamba. As-fabricated NCs were characterized by several analytical and electron microscopic techniques viz. X-ray diffraction (XRD), Fourier Transform-Infrared (FT-IR), Energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), BET (Brunauer-Emmett-Teller), Scanning electron microscopy (SEM), and Transmission electron microscopy (TEM) to evaluate their phases, structure, shape, composition, chemical state, porosity, optical and morphological aspects. The XRD study revealed a cubic spinel symmetry of NCs, while crystallite size estimated around 25 nm. TEM spectroscopy exposed an average particle size 8–10 nm of Co3O4 grown on the surface of reduced graphene oxide (rGO NCs), whereas SEM analysis showed sharped microrubble-shaped morphology. The formation of NCs by doping metal oxide with rGO through in-situ method were confirmed by XRD, EDS, Raman, and XPS spectroscopy. The BET study estimated the specific surface area and pore size of NCs as 98 m2/g and 8.9 nm respectively. The Co3O4–rGO NCs demonstrated an effective bactericidal activity against S. aureus, E. coli, K. pneumoniae, and B. subtillis. Prominently it was found that, a significant antibacterial activity seen against E. coli and S. aureus at a concentration 0.1 mg/100 µL may be due to scaffold morphology, nanoscale-structures and nanoporosity of the NCs. Due to receiving significant antibacterial activity, material’s molecular docking was assessed. Furthermore, an antioxidant activity of leaf extract and NCs was evaluated by DPPH method. An outstanding biological study of bioinspired NCs revealed that material could be used as a potent antimicrobial agent.

Impact of Bismuth (Bi2O3) on physical and spectroscopic studies ZnO–Li2B4O7 glasses modified with Gd3+ ions

The manuscript is to provide information about the preparation, identification of the glassy nature, primary physical parameters and structural studies of Bi2O3 – ZnO – Li2B4O7 – GdF3 glasses. The glasses of thickness around 1 mm were obtained by quenching the molten viscous material onto the moulds. These glasses are transparent enough to recognize them into glassy species but their amorphous nature was scientifically identified with peak free XRD spectra. Several properties like density, molar volume, optical absorption, FTIR, Raman and EPR spectra were measured, analyzed and discussed in detail. Density drastically increased from 2.7715 gm/cc (BZLG-0) to 4.9352 gm/cc (BZLG-40) nearly the increment is (Δρ = 2.1637 gm/cc) is attributed to the presence of bismuth. Molar volume declined to reach from 57.9366 (BZLG-0) to 56.5949 (BZLG-40) glass sample. Optical absorption spectra are flat with no absorption bands except edge transitions. With the concentration of bismuth going from low to high the optical band gap energy 3.281 eV (BZLG-0) shrinks to 2.825 eV (BZLG-40). The band gap decrement is associated with the formation of non-bridging oxygens. FTIR and Raman studies combinedly reveal the existence of certain structural groups and the domination of few borate modes. Observed EPR spectra have shown characteristic resonance signals of the so-called U spectrum typical for Gd3+ ions in disordered systems. In addition to the U-spectrum, an unexpected high crystal field resonance signal is also present.

Structural phase transition, relaxor behavior, and ultra-low strain hysteresis in BaTiO3 ceramics modified by BiYO3

In this study, the structural properties, phase transition, relaxor behavior, and strain properties of (1−x)BaTiO3‒xBiYO3 (x= 0.02‒0.15 mol) ceramics were investigated. The room temperature x-ray diffraction and Raman spectroscopy results reveal that (1−x)BaTiO3‒xBiYO3 ceramics undergo phase transition from tetragonal to pseudo-cubic structure with x increasing. The curves of dielectric constant and loss tangent as a function of temperature and frequency show that the dielectric constant was changing from being dependent on temperature to being independent of it upon increasing BiYO3 amount, which is induced obvious dielectric relaxation behavior. Slimmer polarization–electric field (P–E) loops and lower remnant polarization (Pr ) were observed for samples with x ⩾ 0.08. The transition between the ferroelectric and relaxor states leads to the narrow strain–electric field (S–E) loops, which exhibit a high electric field-induced strain of 0.192% and an ultra-low strain hysteresis of 10.4% at an electric field of 70 kV cm−1 for x= 0.04. This excellent performance indicates that 0.96BaTiO3‒0.04BiYO3 ceramic may be promising lead-free materials for high-precision displacement actuators applications.