Titanate Layer Research Articles

Development of a biosensor based on a surface plasmon resonance structure comprising strontium titanate, graphene and affinity layers for malaria diagnosis

This paper investigates the numerical analysis of a highly performed surface plasmon resonance (SPRE)-based sensor employing a hybrid structure of SrTiO3 (STO) and graphene for rapid detection of malaria. The investigation is performed using the angular interrogation technique and transfer matrix method. The SPRE device has a glass prism, silver (Ag), STO, graphene, affinity layer and sensing medium (SGM). Four coupling prisms are examined and we found the prism N-FK51A corresponds to the highest sensitivity. The sensitivity of the structure N-FK51A/Ag/STO/graphene/affinity layer/SGM is found to be 205.405, 222.222 and [Formula: see text]/RIU for Schizont, Trophozoite and Ring malaria stages. The layer thicknesses are then optimized and it is found that the proposed SPRE sensor can achieve a sensitivity of 278.378, 227.027 and [Formula: see text]/RIU for Schizont, Trophozoite and Ring malaria stages with 30 nm (silver), 1[Formula: see text]nm (STO), mono-sheet of graphene and 5[Formula: see text]nm of the affinity layer. These findings demonstrate that the proposed method and structure can be used efficiently for biomedical applications.

Photoactive nano-confined Pt in titania nanotubes (Pt-TiNT) via microwave-assisted flow synthesis

Pt-TiNT with PtO nanoparticles dispersed within the lumen and interlayer spaces of titania nanotubes (TiNT) were prepared by a new process involving titanate nanosheets (TiNS) synthesis in an optimized microwave-assisted flow reactor, followed by ion-exchange with a Pt precursor, before triggering the titanate layer rolling to trap the Pt precursor clusters inside the titania nanotubes, followed by a thermal treatment. TEM, XRD, and Raman analyses confirm the total conversion of TiO2 into TiNS in 15 min at 120 °C and 4 bar, and the TiNS transformation into 181 nm-long TiNT with 10 and 6 nm outer and inner diameter, respectively. The 2% Pt-TiNT comprises 0.7 nm PtO clusters (according to XPS), causing slight distortions of the interlayer spaces, while a few larger 2–3 nm Pt clusters reside within the lumen. As a result, Pt-TiNT is 14-fold more active than TiNT for visible light (400–780 nm) photocatalytic oxidation of diclofenac under 2136 μW·cm−2 irradiation, and>1000-fold better than the uncatalyzed photoconversion reaction under 100 mW·cm−2 artificial solar lighting. In addition, nano-confinement of PtO clusters narrowed the bandgap of the TiNT, which, combined with its excellent absorptivity to harvest light, allowed a broader spectral range of photon energies to activate the photocatalyst.

Магнитоимпеданс в планарной магнитоэлектрической гетероструктуре аморфный ферромагнетик-пьезоэлектрик: модуляция электрическим полем

The magnetoimpedance effect and the converse magnetoelectric effect in a planar heterostructure consisting of mechanically bonded layers of amorphous ferromagnet FeBSiC and piezoelectric lead zirconate titanate are studied. Magnetoimpedance was observed in the frequency range of 0.1-40 MHz and bias dc magnetic field of 0-300 Oe; the maximum magnitude of the effect at a frequency of 10 MHz reached 12%. The converse magnetoelectric effect was observed in magnetic fields of 0-50 Oe; the maximum value of the effect at the structure acoustic resonance frequency of 40 kHz was 1.45 G/(V/cm). Amplitude modulation of the magnetoimpedance by an electric field at the resonance frequency of the structure with a coefficient of ~1∙10─2 is found. Modulation occurs as a result of a combination of the piezoelectricity and magnetostriction of the layers, which leads to a change in the transverse magnetic permeability and the thickness of the skin-layer of the ferromagnet.

Conferring Antioxidant Activity to an Antibacterial and Bioactive Titanium Surface through the Grafting of a Natural Extract.

The main unmet medical need of bone implants is multifunctional activity, including their ability to induce rapid and physiological osseointegration, counteract bacterial biofilm formation, and prevent in situ chronic inflammation at the same time. This research starts from an already developed c.p. titanium surface with proven bioactive (in vitro hydroxyl apatite precipitation) and antibacterial activities, due to a calcium titanate layer with nano- and micro-scale roughness and loaded with iodine ions. Here, antioxidant ability was added to prevent chronic inflammation by grafting polyphenols of a green tea extract onto the surface, without compromising the other functionalities of the surface. The surface was characterized before and after functionalization through XPS analysis, zeta potential titrations, ion release measurements, in vitro bioactivity tests, SEM and fluorescence microscopy, and Folin-Ciocalteu and biological tests. The presence of grafted polyphenols as a homogeneous layer was proven. The grafted polyphenols maintained their antioxidant ability and were anchored to the surface through the linking action of Ca2+ ions added to the functionalizing solution. Iodine ion release, cytocompatibility towards human mesenchymal stem cells (hMSC), and antibacterial activity were maintained even after functionalization. The antioxidant ability of the functionalized surface was effective in preserving hMSC viability in a chemically induced pro-inflammatory environment, thus showing a scavenger activity towards toxic active species responsible for inflammation.

Surface competition between osteoblasts and bacteria on silver-doped bioactive titanium implant

The rapid integration in the bone tissue and the prevention of bacterial infection are key for the success of the implant. In this regard, a silver (Ag)-doped thermochemical treatment that generate an Ag-doped calcium titanate layer on titanium (Ti) implants was previously developed by our group to improve the bone-bonding ability and provide antibacterial activity. In the present study, the biological and antibacterial potential of this coating has been further studied. In order to prove that the Ag-doped layer has an antibacterial effect with no detrimental effect on the bone cells, the behavior of osteoblast-like cells in terms of cell adhesion, morphology, proliferation and differentiation was evaluated, and the biofilm inhibition capacity was assessed. Moreover, the competition by the surface between cell and bacteria was carried out in two different co-culture methods. Finally, the treatment was applied to porous Ti implants to study in vivo osteointegration. The results show that the incorporation of Ag inhibits the biofilm formation and has no effect on the performance of osteoblast-like cells. Therefore, it can be concluded that the Ag-doped surface is capable of preventing bone bacterial infection and providing suitable osseointegration.

Nd3+-Ion-Sensitized PZT:Er3+/Yb3+ Gradient Luminescent Layers Using Pulsed Laser Deposition as Alternative to Microlens Array Arrangement for Improving Efficiency of Si Solar Photovoltaic

Using the pulsed laser deposition (PLD) technique via Nd:YAG laser ablation, a transparent luminescent phosphor thin film of homogeneous thickness was created that could effectively absorb both near-infrared (NIR) and ultraviolet (UV) light while simultaneously upconverting and downconverting it to visible light. In single-junction microcrystalline silicon solar photovoltaics (SPV), the use of the gradient luminous phosphor Nd3+-sensitized Er3+/Yb3+ codoped zirconate titanate (PZT) layer was examined. The addition of an Nd3+/Er3+/Yb3+ doped PZT luminescent layer to the back of the solar cell could dramatically extend the lifetime of the device when compared to that of a reference Si solar cell. The proposed model’s light motion was also examined using a theoretical simulation (COMSOL). An attempt was made to find an alternative to existing luminescent solar cell concentrators, i.e., microlens array (MLA) configuration, that functions as spatial light modulators in solar cells in this work. The reported gradient phosphor three-layer design is unique and works as an efficient light-trapping design following the phenomena of total internal reflection in multimode optical fibers. The proposed solar photovoltaics was also created with a nanomirror configuration employing semiconductor nanoparticles for effective light absorption in the back reflector layer. When compared to Si-SPV without the luminescent layer, the frequency upconverted visible emissions can be reabsorbed by the SPV and boost the photocurrent, which increases the overall fill factor from 5.30 to 5.99%. The current methodology offers a simple approach for a high-performance luminescent SPV design.

Epitaxial bilayer La0.7Sr0.3MnO3/Ba0.7Sr0.3TiO3 thin films obtained by polymer assisted deposition

In this work bilayer structures, composed of ferromagnetic manganite and ferroelectric titanate layers, were obtained by solution deposition technique. The first step in preparation of the bilayer thin films was deposition of manganite (LaMnO3 or La0.7Sr0.3MnO3) layer by water-based polymer assisted deposition (PAD). Polycrystalline structures were obtained when manganite films were deposited by spin coating on commercial Pt/TiO2/SiO2/Si type substrate, whereas epitaxial films were grown on a single crystal SrTiO3 with (001) orientation substrate. The second ferroelectric titanate (BaTiO3 or Ba0.7Sr0.3TiO3) layer was deposited by spin coating using sol-gel method. The obtained bilayer structures have thickness below 100 nm, and epitaxial growth of the Ba0.7Sr0.3TiO3 film on the La0.7Sr0.3MnO3 surface was obtained, due to the similar lattice parameters between these two crystal structures.

Contribution of the lamellar morphology to the photocatalytic activity of alkaline-hydrothermally treated titania in rhodamine B photodegradation.

TiO2 particles with a specific morphology are essential for their accessibility and photoactivity. The present study shows that NH4OH-based alkaline-hydrothermal treatment affects the transformation of their particle morphology. We investigated the effect of NH4OH by varying the synthesis route. We observed that the TiO2 particles with an open channel pore structure only resulted in the alkaline-hydrothermally treated and calcined samples. Based on Raman and XRD analyses, we figured out the titanate layers as an intermediate phase resulting from the alkaline-hydrothermal treatment of the amorphous particles. The hydrothermal treatment changed the particle surface morphology into a lamellar structure with a high specific surface area. These are the anatase precursors with {200} planes that transform into the anatase phase after calcination. The calcination followed by alkaline-hydrothermal treatment converted the crystallinity without significantly changing their morphology. We found that the morphology of TiO2 particles can be modified via hydrothermal treatment using NH4OH as long as the particles remain uncrystallized. We suggested the modification of particle morphology through the swelling and phase segregation process by alkaline-hydrothermal treatment. All final products have been used for the photodegradation of rhodamine B. S-HT-500 and A-HT-500 show the best photocatalytic activity with their rate constants (k) of 47.9 and 30.9 × 10-2 min-1, and their surface area-normalized rate constants (ksa) of 6.5 and 2.6 × 10-3 L m-2 min-1, respectively, and have a photocatalytic efficiency of 90.93% and 67.78%, respectively, after 10 minutes of UV irradiation. This activity is approximately 3.5 times and 1.5 times higher than that of Degussa P25; 30 times and 20 times higher than that without a photocatalyst.

Nanostructured, Alkaline Titanate‐Converted, and Heat‐Treated Ti6Al4V Microspheres via Wet‐Chemical Alkaline Modification and their ORR Electrocatalytic Response

AbstractThis study describes the chemical conversion and heat treatment of Ti6Al4V microspheres (Ti6_MS), and the resulting effects on their electrocatalytic properties. The wet‐chemical conversion (5.0 m NaOH, 60 °C, 24 h; Sample label: Ti6_TC) converts the top surface of the Ti6_MS powder into an ≈820 nm thick sodium titanate surface. Heat‐treatment (Ti6_TC_HT) at 450 °C increases the stability of the surface, through partial titanate crystallization, while mitigating excess rutile formation. All samples are analyzed chemically (XPS, EDX, Raman, EELS), structurally (XRD and TEM), and morphologically (SEM, TEM), demonstrating the characteristic formation of sodium titanate dendritic structures, with minimal chemical, structural, and morphological differences due to the 450 °C heat‐treatment. The effect of the preparation methodology on oxygen reduction reaction (ORR) electrocatalytic performance is also tested. The introduction of the sodium titanate layer changes the mechanism of the ORR, from a mixed 4 electron/2 electron pathway to a predominantly 2‐electron pathway. By maintaining the microspherical nature of the material while also tuning the surface of the material toward different reaction mechanisms, a design strategy for new electrocatalyst materials is explored.

TiO2/HA and Titanate/HA Double-Layer Coatings on Ti6Al4V Surface and Their Influence on In Vitro Cell Growth and Osteogenic Potential.

Hydroxyapatite (HA) layers are appropriate biomaterials for use in the modification of the surface of implants produced inter alia from a Ti6Al4V alloy. The issue that must be solved is to provide implants with appropriate biointegration properties, enabling the permanent link between them and bone tissues, which is not so easy with the HA layer. Our proposition is the use of the intermediate layer ((IL) = TiO2, and titanate layers) to successfully link the HA coating to a metal substrate (Ti6Al4V). The morphology, structure, and chemical composition of Ti6Al4V/IL/HA systems were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectrometry (EDS). We evaluated the apatite-forming ability on the surface of the layer in simulated body fluid. We investigated the effects of the obtained systems on the viability and growth of human MG-63 osteoblast-like cells, mouse L929 fibroblasts, and adipose-derived human mesenchymal stem cells (ADSCs) in vitro, as well as on their osteogenic properties. Based on the obtained results, we can conclude that both investigated systems reflect the physiological environment of bone tissue and create a biocompatible surface supporting cell growth. However, the nanoporous TiO2 intermediate layer with osteogenesis-supportive activity seems most promising for the practical application of Ti6Al4V/TiO2/HA as a system of bone tissue regeneration.

A microstructural study on the alkali-treated titanium subjected to induction heating

Alkali-treated titanium and its alloys (with or without heat treatment) have been paid more attention in the biomaterial field for the formation of a nanoporous layer that can induce apatite deposition and improve bone-implant integration. In this work, a hierarchical micro-nano structure was fabricated by alkali treatment and subsequent induction heating at different temperatures. The surface morphology, phase composition, microstructure, and elemental binding state were investigated using scanning electron microscopy (SEM), X-ray diffractometer (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS), respectively. As the induction heating temperature increases, the porous structure of the outmost sodium titanate layer is maintained with increased anatase TiO2 and decreased wetting angle from 21.8° to 11.8°. At a relatively high temperature (700 °C), the composite layer is composed of a porous sodium titanate layer with a thickness of around 1 μm and a titanium oxide layer of about 2 μm thickness with nanopores. Importantly, the amorphous structure with the oxygen vacancy that exists on the sample surface is conducive to apatite deposition. The assessment of the in-vitro bioactivity performed in 1.5 simulated body fluid shows that the ability to induce apatite deposition increases with the increasing induction heating temperature from 500 to 700 °C. These results are helpful to understand the microstructure of the alkali and induction heating treated titanium that may be responsible for its bioactivity.

The influence of biological active layer to titanium alloy biocompatibility in vitro

we can obtain porous netshaped conformation after activate treatment, such conformation will make area of the sample surface increase, surface energy increase. Reticular conformation and nanometer hole structure increase the combination intensity with the bone. As implanted material, for human bone tissue through the mesh-like surface of the conditions of the exchange offer. Therefore, bionic activation layer/titanium biomedical materials may become the optimization implant materials for its excellent biological properties. In the course of simulated body fluid (SBF) cultivation, Titanate gel layer in simulated body fluid absorpt calcium ion, hydroxyapatite in titanate layer of porous network structure form nuclear and grow up and induced deposition a certain orientation of the bone-like apatite.

Detection of glucose concentration using a surface plasmon resonance biosensor based on barium titanate layers and molybdenum disulphide sheets

Diabetes is rapidly becoming a serious and life-threatening disease. It affects 415 million persons worldwide and is a leading cause of death among those aged 20 to 59. It is essential to develop a rapid-detection, accurate and sensitive glucose detector. In this work, a biosensor based on surface plasmon resonance (SPR) is proposed theoretically for the detection of glucose concentration. To realize higher sensitivity, the proposed SPR sensor contains a barium titanate layer placed between the metal (Ag) thin film and the molybdenum disulphide layer. Barium titanate material shows notable dielectric properties, such as low loss and a high index of refraction. It is expected to give a large shift in the resonance angle caused by a tiny change in the analyte refractive index. By optimizing the thicknesses of barium titanate and Ag and the number of molybdenum disulphide layers, the proposed biosensor can exhibit an ultra-high sensitivity of 307.36 deg RIU−1. The extremely high sensitivity makes the proposed SPR-based biosensor encouraging to be used in many fields of biosensing.

An Electromechanical Model for Clamped-Edge Bimorph Disk Type Piezoelectric Transformer Utilizing Kirchhoff Thin Plate Theory.

In this paper, an analytical solution for a clamped-edge bimorph disk-type piezoelectric transformer with Kirchhoff thin plate theory is proposed. The electromechanical equations for transient motions are first derived, and coupled expressions for mechanical response and voltage output are obtained. For the case of excitation around the first resonant frequency, the resulting equations are further simplified. There are analytical solutions for a mechanical response, voltage, current, and power outputs. According to the analytical model, the output voltage is affected by the inner radius of the input and output electrodes, the radius of the piezoelectric transformer (PT), and the thickness ratio between the lead zirconate titanate (PZT) layer and the substrate. When the inner radius of the input electrode approaches zero (electrode becomes circular shape), it achieves maximum output voltage at the first resonance frequency excitation. On the contrary, when the inner radius of the output electrode approaches zero, the output voltage reaches its minimum value. Voltage ratios remain constant as the disk radius changes, and the first resonance frequency is inversely proportional to the square of the disk radius. The voltage ratio is fixed even with the miniaturization of the PT.

Atomic-resolution investigation of structural transformation caused by oxygen vacancy in La0.9Sr0.1TiO3+ titanate layer perovskite ceramics

• The formation process, migration behavior, and microstructure effects of oxygen vacancies on overlapping layered structure perovskite La 0.9 Sr 0.1 TiO 3+δ were investigated systematically. • New discoveries enhance the understanding of lattice defects in layered perovskite oxides and the lattice transformation mechanism caused by oxygen vacancies on atomic-resolution scale. • Providing an approach to reveal how oxygen vacancy disables lower optical property in layer perovskite functional materials. Perovskite functional ceramics have been widely applied for thermal protection owing to their unique physical properties. However, formation of oxygen vacancies under external stimuli usually limits their performance in practical applications. Therefore, the mechanism of the effect of oxygen vacancy on the layer structure of perovskite La 0.9 Sr 0.1 TiO 3+ δ was investigated by experiments and first-principles simulations. The experimental results showed that the lattice distortion occurred in oxygen-deficient environment to give a longer c -axis, along with a significant adjustment in the modes of A/B–O bond vibration, resulting in lower reflectivity. Advanced transmission electron microscopy studies revealed that oxygen vacancies induced localized atomic rearrangements via [TiO 6 ] layer movements to adapt to the lattice distortion. This eventually restructured a part of the layer interfaces by expanding the overlapping projection of atoms in the c -axial direction. The specific transformation process was described as a compendious process, while geometric phase analysis effectively clarified how oxygen vacancies can inhibit reflectivity on the layer structure. Thus, this study provides effective approaches for researching the effects of oxygen vacancy on the physical properties of orthorhombic layer perovskite structures, which may facilitate the development of perovskite-based functional devices.

Study of the Layer-Type BST Thin Film with X-ray Diffraction and X-ray Photoelectron Spectroscopy

In the present paper, results of X-ray photoelectron studies of electroceramic thin films of barium strontium titanate, Ba1−xSrxTiO3 (BST), composition deposited on stainless-steel substrates are presented. The thin films were prepared by the sol-gel method. A spin-coating deposition of BST layers with different chemical compositions was utilized so the layer-type structure of (0-2) connectivity was formed. After the deposition, the thin-film samples were heated in air atmosphere at temperature T = 700 °C for 1 h. The surfaces of BST thin films subjected to thermal treatment were studied by X-ray diffraction. X-ray diffraction measurements confirmed the perovskite-type phase for all grown thin-film samples. The oxidation states of the elements were examined by the X-ray photoelectron spectroscopy method. X-ray photoelectron spectroscopy survey spectra as well as high-resolution spectra (photo-peaks) of the main metallic elements, such as Ti, Ba, and Sr, were compared for the layer-type structures, differing in the deposition sequence of the barium strontium titanate layers constituting the BST thin film.

Nanostructured Strontium Titanate Perovskite Hyperbolic Metamaterial Supported Tunable Broadband THz Brewster Modulator

The investigation was made of nanostructured intensity and phase modulators, the designs of which are based on Brewster angle manipulation. The configuration consists of thin indium tin oxide, strontium titanate and quartz layers embedded on silicon substrate. The structure exhibits elliptical and hyperbolic metamaterial kinds, which can be manipulated by varying the ambient temperature. The design yields broadband intensity and phase modulator with 99.8% modulation depth and perfect phase shift (i.e., 180°), respectively, at the room temperature. This would find potentials in active polarization switches, modulators and tunable phase shifters operating in the THz regime.

Effect of electrochemical modification of titanium hydride fraction on oxygen content in surface and deep layers

The paper presents a study of the microstructure and oxygen concentration in the surface and deep layers of fractions of unmodified titanium hydride and titanium hydride modified by electrodeposited layers of Ti and Cu at temperatures of 300 °C–900 °C. The composition of the oxide layer and the concentration of titanium and oxygen atoms are estimated. It is shown that an increase in the thickness and compaction of the oxide layer with increasing temperature prevents the penetration of oxygen into the deep layers of the unmodified fraction of titanium hydride. Modification of titanium hydride by electrochemical deposition of metallic titanium at a temperature of 700 °C reduces the oxygen concentration in titanium hydride at a layer depth of 50 μm from 35 wt% to 12.5 wt%. Electrodeposition of coatings based on titanium and copper at 700 °C reduces the oxygen concentration to 9.2 wt%, which may be due to the protective mechanism of the formed copper titanate layer. At 900 °C, in the modification layer based on titanium and copper, due to the eutectoid transformation of the β-phase of titanium, the process of contact melting occurs and a multiphase zone is formed. The oxygen concentration at a layer depth of 50 μm is no more than 12.4 wt%.

Low cost, contamination-free, and damage-free fabrication of PZT MEMS on SOI substrate

This paper reports a generalised process flow for the fabrication of lead zirconate titanate based piezoelectric micro electromechanical system devices. The optimised process can be used to realise several devices with different 1D and 2D geometries on a single wafer. All the state-of-the-art fabrication methods introduce some damage to the active piezoelectric material. This damage entails the need for an additional step of recovery anneal in the fabrication process. Our process was designed and optimised to avoid any such damage to the Lead Zirconate Titanate (PZT) layer. Remnant polarisation and effective transverse piezoelectric coefficient (e 31, f ) were used as metrics to quantify the damage to the PZT layer. It is shown that our process does not damage the PZT thin film during the fabrication, and hence no recovery anneal is required. We observe a ∼3× improvement in remnant polarisation and ∼2× improvement in e 31, f of PZT thin film compared to the PZT thin film subjected to our previous fabrication process. Moreover, the process explained here uses only wet chemical methods for patterning of contaminating agents (PZT and platinum), making it a cost-effective process.

Influence of graded doping on the long-term reliability of Nb-doped lead zirconate titanate films

Niobium doped lead zirconate titanate (PNZT) films show potential in piezoelectric microelectromechanical systems (piezoMEMS); their long-term reliability is important for successful application. This work describes how variations in the doping profile through the film depth can significantly increase the long-term reliability of PNZT films, while retaining excellent piezoelectric properties. Chemical solution derived {100} textured PNZT films were prepared with a Mn-doped lead zirconate titanate (PMZT) layer at the film top or bottom surface (PNZT + x mol% PMZT, or x mol% PMZT + PNZT). No significant differences were found in the baseline dielectric, ferroelectric and piezoelectric properties of the films. As the Mn-doping concentration increased, the medium time to failure (t50) of PNZT + x mol% PMZT and x mol% PMZT + PNZT films gradually increased from 14.4 h to 93.9 hours, and from 27.7 to 94.6 hours, respectively, under aggressive test conditions (200°C, 300 kV/cm) where the Mn doped layer served as the cathode. Current – voltage measurement on pristine PNZT + 2 mol% PMZT films showed Schottky emission-controlled conduction. After a 23 hours degradation period at 200°C, 300 kV/cm (field up), Poole-Frenkel conduction became dominant. The trap energy level increased from 0.45 ± 0.01 eV for PNZT to 1.27 ± 0.03 eV for the PNZT + 2 mol% PMZT film. Furthermore, Ti4+ reduction was found in degraded PNZT near the top electrode, but not in degraded PNZT + 2 mol% PMZT, as recorded by electron energy loss spectroscopy data. Electron trapping by Mn ions showed strong contributions to suppression of the conduction and improvement of long-term reliability for the PNZT film with a PMZT (top or bottom) layer.