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In this paper, an efficient room temperature ethanol sensor device based on p-n homojunction of p-TiO2 nanoparticles (NPs) and n-TiO2 nanotubes (NTs) is reported. p-TiO2 NPs were prepared by low-temperature sol–gel method and coated on n-TiO2 NTs (NPs) grown by electrochemical anodization. Field emission scanning electron microscopy and X-ray diffraction authenticated the formation of stable homojunction between p-type anatase TiO2 NPs and n-type anatase TiO2 NTs. Current–voltage characteristics of the device, in the lower voltage range (0–1.26 V) for 30 °C, followed nonlinear characteristics (Schottky). With increase in voltages (>1.26 V) and temperature (40 °C–100 °C) such nonlinear behavior moves toward more linear ones. The gas sensing performance of the homojunction device was studied at room temperature with alcohols as the test species. The device offered the maximum response magnitude of ~57% (toward ethanol) at 100 ppm with appreciably fast response time and recovery time of ~30 and ~16 s, respectively. Dramatic increase in the effective depletion region area distributed throughout the nanotubular voids and the associated localized electric filed originated from the electrostatic charge separation therein (which helps in easy dissociation of target species) is possibly responsible for such efficient room temperature sensing performance. [ABSTRACT FROM AUTHOR]

In this paper a simple, low-cost, green method for the synthesis of TiO2/CDs (CDT) photocatalyst using kitchen waste product with increased photocatalytic activity under UV–Vis. light has been described. Carbon dots (CDs) are produced from waste tea powder residue by simple carbonization and grafted on TiO2 by sol–gel method to produce nanocomposite with size less than 20 nm. The XRD patterns indicate the presence of anatase TiO2 in all the CDT nanocomposites. TEM images show the size of nanoparticles ranging between 2 and 10 nm. The Ti–O–C vibrations create a band below 1000 cm−1. The UV–Vis spectra show that the CDs absorb the light in the visible region between 400 and 450 nm and the redshift in CDT-2 governing decrease in band gap energy. The surface area of pristine TiO2 and CDT-2 are 66 and 187 m2 g−1, respectively. The CDT-2 composite shows enhanced photocatalytic activity which is double than TiO2. [ABSTRACT FROM AUTHOR]

Antireflective (AR) coatings can suppress the undesired interfacial Fresnel reflections, and they are widely used in optical devices and energy-related instruments. Conventional single-layer AR coatings, which only work at a single wavelength, encounter serious limitations in some practical applications because of their inherent properties. In this paper, λ/4–λ/4 double-layer antireflective (AR) coatings with constant high transmittance in a pre-determined wavelength range was prepared by the sol–gel method via acid-catalyzed and base-catalyzed SiO2 thin films. A double-layer antireflective coating with an almost constant transmittance value of 99.8% in the range of 550–700 nm was obtained, and the transmittance of this coating was higher than 99% in a wider range of 450–850 nm with a fluctuation of less than 1%. The coatings had good environmental stability and maintained constant high transmittance after two weeks of exposure in 50% humidity. The broadband AR coatings may have important applications in fields such as electroluminescent display. [ABSTRACT FROM AUTHOR]

Nanoparticle enhancement has been used as an effective means to improve the performance of biomass adhesives. However, there is an inevitable problem of stress concentration caused by particle agglomeration and thus the adhesive layer is susceptible to damage. Therefore, in this paper, a sol–gel method was used to generate uniformly distributed manganese dioxide (MnO2) nanoparticles on the surface of diatomite (Dia) and used for the modification of soybean meal based wood adhesives. The results showed that MnO2 nanoparticles have been successfully anchored on the surface of Dia during the sol–gel process without agglomeration. MnO2/Dia particles could fill in the adhesive gaps and form hydrogen bonds with soy protein molecules, which ensured that the adhesive wet shear strength was increased by 33% to 0.89 MPa. This study provided an idea for the preparation of highly dispersed nanoparticle reinforced adhesives. [ABSTRACT FROM AUTHOR]

This paper reports a potential and easy method to prepare nickel ferrite nanoparticles with improved dielectric and magnetic properties by doping with zinc. The structural studies and Rietveld refinement of the XRD pattern confirm the cubic spinel structure of the ferrite phase belonging to the Fd3m space group. Morphological and elemental composition analyses of the prepared samples are carried out using scanning electron microscopy and energy dispersive spectroscopy (EDAX). The frequency variation of the dielectric constant and ac conductivity have been studied. The dependence of dielectric constant and ac conductivity on the frequency of the alternating applied electric field is explained by the Maxwell–Wagner model. The zinc doping in nickel ferrite nanoparticles is helpful in modifying the dielectric properties and thereby designing materials matching the application requirements. Magnetic measurements were carried out at 300 K and 5 K points toward an enhanced magnetic property in zinc-doped samples. The saturation magnetization value for zinc ferrite nanoparticles is around 23 emu/g at 300 K and 56 emu/g at 5 K which clearly indicates the superparamagnetic behavior of the samples. The maximum value for Ms is obtained for the Ni0.5Zn0.5Fe2O4 sample which is 74 emu/g and 101 emu/g at 300 and 5 K, respectively. The enhanced dielectric and magnetic properties inherited by Zn doping in nickel ferrite (NFO) nanoparticles suggest the improved potential of these superparamagnetic NZFO nanoparticles for various applications. [ABSTRACT FROM AUTHOR]

Dry desulfurization technology is one of the important means of flue gas desulfurization and SO2 control. In this paper, a series of desulfurizers with zinc oxide as the active component and bentonite as the carrier were prepared by the sol–gel method. The performance of the desulfurizers under different preparation process conditions were studied, and they were characterized by ICP, XRD, FTIR, BET and SEM. The result showed that active component loading, molar ratio to citric acid, calcination time and calcination temperature were all important factors that affected the efficiency of the desulfurizers. The desulfurizer prepared by the sol–gel method had a loading amount close to the theory, and the active components were uniformly loaded on the carrier. [ABSTRACT FROM AUTHOR]

Hydroxyapatite (HA or HAp) is one of the most preferred biomaterials, specifically for bone tissue engineering. HAp is available naturally and is also chemically synthesized. The properties, shape, size and crystalline structure and applications of HAp vary widely depending on the source and extraction methods used. In addition to conventional chemical approaches such as precipitation or sol-gel techniques, newer methods such as microwave synthesis and atomic-layer deposition provide an opportunity to generate HAp with desirable structure and properties. Various methods used for the synthesis of HAp have their own pros and cons. Hence, it is essential to understand the role of specific methods and conditions on the properties and structure of HAps in order to obtain HAp with properties suitable for specific applications. In addition to pure HAp, substantial efforts have been made to dope HAp with various minerals or bioentities to enhance their suitability for medical, environmental remediation and other approaches. In this review, we provide an overview of the various chemical methods used to produce HAp, properties of the HAp produced and its potential applications. Particular focus of this paper is on the co-relation between properties and processes used to synthesis HAp. This review will enable readers to quickly understand the importance of synthesis methods and conditions on the properties of HAp and choose appropriate means to generate HAp with desired properties for specific applications. [ABSTRACT FROM AUTHOR]

Copyright of New Building Materials / Xinxing Jianzhu Cailiao is the property of New Building Materials Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: A series of tin‐nanoparticle/carbon‐nanofiber composites with varied tin content were synthesized by employing natural cellulose (e.g., ordinary laboratory filter paper) as both the structural scaffold and carbon source. The nanocomposites were obtained through hydrogen reduction of nanofibrous tin‐oxide/carbon hybrids that were prepared by a self‐assembly technique based on the surface sol–gel process. The nanocomposite with 16 wt % tin content was composed of fine metallic tin nanocrystallites with sizes of 20–50 nm that were uniformly immobilized on the surface of the cellulose‐derived carbon nanofibers. When employed as an anodic material for lithium‐ion batteries, because of its unique three‐dimensionally hierarchical porous structures and the buffering effect of the carbon matrix, it showed a stable discharge capacity of ca. 430 mAh g−1 after 200 charge/discharge cycles at a current density of 100 mA g−1, which was close to the calculated theoretical capacity of the electrode. In addition, its structural stability upon extensive charge/discharge cycling processes is outstanding. [ABSTRACT FROM AUTHOR]

Nowadays, the poor conductivity and unstable structure have become obstacles for the popularization of Na3V2(PO4)3 (NVP). In the current work, a dual-modified Mn0.1Cl0.3-NVP composite doped with Mn and Cl is prepared by a facile sol–gel method. When Mn2+ with a large ionic radius replaces small V3+, it can improve the stability of the NVP crystal structure. In addition, the replacement of V3+ by Mn2+ in a low valence state can generate redundant hole carriers, which is conducive to the rapid transport of electrons. The substitution of PO43− by Cl−, which is more electronegative, can reduce the impedance and facilitate the movement of Na+. Owing to the synergistic effect of Mn and Cl co-substitution, the structural stability of NVP was systematically enhanced, and the electron transfer and ion diffusion were effectively improved. Consequently, the optimized Mn0.1Cl0.3-NVP sample demonstrated superior electrochemical performance and kinetic properties. It exhibited a high reversible capacity of 109.2 mA h g−1 at 0.1C. Even at 15 and 30C, high discharge capacities of 70.3 mA h g−1 and 68.2 mA h g−1 were observed after 2000 cycles with capacity retention above 80%. Moreover, it delivered remarkable capacities of 77.1 and 73.4 mA h g−1 at 100 and 200C with retained capacity values of 50.3 and 47 mA h g−1, respectively, after 2000 cycles. Furthermore, the assembled Mn0.1Cl0.3-NVP//HC full cell delivered a high value of 94.7 mA h g−1 and lit LED bulbs, indicating its excellent application potential. [ABSTRACT FROM AUTHOR]

Herein, hollow hZrO2/g-C3N4 composite photocatalysts were successfully fabricated using polymethylacrylic acid (PMAA) nanospheres as sacrificial templates via reflux-precipitation polymerization and subsequent ZrO2 layer coating by sol–gel method over PMAA nanospheres, calcining process, and forming composites with g-C3N4 in sequence. The formation mechanism of the unique composites was proved by FESEM, TEM, XPS, XRD, and EDX mapping characterizations. The photodegradation tests of methylene blue (MB) and ciprofloxacin (CIP) were used to investigate the photocatalytic activity. The results revealed that hZrO2/g-C3N4 exhibited significantly boosted photocatalytic activity for degrading 99.7% methylene blue and 81.5% ciprofloxacin in 120 min under simulated sunlight irradiation (Xe lamp, 500 W), which was much better than that of hZrO2 (42.1% for MB and 19.1% for CIP). The enhanced performance is presumably attributed to the synergetic interaction of the two components and the efficient separation of the photoproduced electron–hole pairs between ZrO2 and g-C3N4, which was verified using photocurrent and EIS characterizations. On the basis of the scavenging studies of free radicals (e−, h+, ˙O2−, and ˙OH), the mechanism of the boosted photocatalytic activity was proposed. More significantly, the composites presented excellent reusability confirmed by cyclic photocatalytic degradation experiments, which is crucial for the sustainable and green applications of photocatalysts. [ABSTRACT FROM AUTHOR]

In our present paper, the morphological, structural and electrical properties of chromium-doped BaTiO 3 ceramics were investigated. BaTi 0.5 (Cr 0.33 Mo 0.17)O 3 was prepared by the sol-gel technique. Tetragonal phase with P4mm space group was observed by X-ray diffraction analysis. An excellent agreement between the calculated and the observed model was verified by Rietveld refinement. A polycrystalline compound with a particle size of 1.96 μm was identified using scanning electron microscopy. The electrical conductivity graph is divided into two regions in the frequency interval 102–106 Hz over the temperature range 480–640 K. The Ac conductivity spectrum follows the Jonscher's law. The conductivity mechanism in the studied temperature range can be explained by the Non-overlapping Small Polaron Tunnel (NSPT) model. The imaginary parts of impedance show that the maximum value of Z″ decrease with temperature rise, reflecting the progressive loss of insulating properties. In addition, the peaks of Z″ shifted to higher frequencies, indicating relaxation behaviour. Furthermore, the real part of Z″ decreased with temperature and frequency increase, indicating Negative Temperature Coefficient Resistance (NTCR) behaviour. The complex impedance plot showed large semicircular arcs corresponding to the merging of two semicircles due to grain and grain boundary contribution. Examination of the impedance and modulus normalization curves revealed a shift in both peaks, indicating the existence of a short moving carrier. The exponent "n" increased with temperature increase, which proves the existence of the Non-overlapping Small Polaron Tunnel (NSPT) model in the studied temperature range. [ABSTRACT FROM AUTHOR]

This paper reports the effect of lanthanum addition on the structural and electrical properties of (Pb 1-x La x)(Zr 0.65 Ti 0.35)O 3 (PLZT x/65/35, x = 8%,10%,12%,15%) ceramics near the morphotropic phase boundary. Studies were conducted on the PLZT x/65/35 ceramics synthesized via a combinatorial approach of high-energy ball milling (mechanical activation method) followed by Cold Isostatic Pressing (CIP). Due to the application of CIP, PLZT ceramics exhibited improved density and a closely packed microstructure. The SEM analysis showed that PLZT x/65/35 ceramics exhibited an increase in grain size with higher concentrations of La3+ ions. Room temperature X-ray diffraction results revealed the formation of perovskite PLZT phase. The investigation on temperature-dependent dielectric, ferroelectric properties of PLZT x/65/35 ceramics provided experimental confirmation of structures cited in XRD analysis. Among all the compositions, PLZT 8/65/35 samples showed a well saturated, uniform P–E hysteresis loop with a high remanent polarization (P r). Poled PLZT 8/65/35 samples displayed electric field induced large strains with limited hysteresis. Piezoelectric charge coefficients (d 33), electromechanical coupling factors (k p , k 33 , k 31) were determined for poled PLZT x/65/35 ceramics and it was found that PLZT 8/65/35 ceramics reveal properties superior to other compositions. Furthermore, the unipolar strain, P r , d 33 , k p , k 33 , k 31 values of PLZT 8/65/35 composition exceeded the previously reported ones for the same composition prepared via sol-gel synthesis technique. [ABSTRACT FROM AUTHOR]

Polyanion-type positive electrode active materials such as LiFePO4 are promising materials for high-safety lithium-ion batteries because of their highly stable anion structure. However, polyanion-based positive electrode active materials with high energy densities and good safety features are more desirable than LiFePO4 at present. Among the polyanionic materials, Li2MAO4 (M = Mn, Fe; A = Si, Ge) systems have high theoretical capacities owing to their two-electron redox in many cases, and these materials are synthesized using sol–gel or solid-phase methods. This study provides a more simple and environmentally friendly method for the aqueous synthesis of Li2MAO4via an acid–base reaction. The material could be simultaneously composited with carbonized carbon. Li2MnGexSi1−xO4/C (x = 0, 0.5, 1.0) and metal substituted Li2Mn0.8Fe0.2SiO4/C and Li2Mn0.8Fe0.2GeO4/C were successfully prepared, and showed discharge capacities of 195 mA h g−1 and 178 mA h g−1, respectively, at 0.13 mA cm−2 and 25 °C. Thus, the developed method can be effectively used to fabricate polyanion-type positive electrode active materials. [ABSTRACT FROM AUTHOR]

This paper presents simulation, fabrication, and characterization of single-element ultrahigh frequency (100–300-MHz) needle ultrasonic transducers based on 0–3 composite Pb(Zr0.52Ti0.48)O3 (PZT) films prepared by using composite ceramic sol-gel film and sol-infiltration technique. The center frequency of the developed transducer at 300-MHz was the highest frequency of PbTiO3 ceramic-based ultrasonic transducers ever reported. Furthermore, a brief description of the composite model was followed by the development of a new expression for predicting the longitudinal velocity, the clamped dielectric constant, and the complex electromechanical coupling coefficient kt of these films, which is very important in ultrasonic transducer design. Moreover, these parameters are difficult to obtain by measuring the frequency dependence of impedance and phase angle because of the weak signal of the previous 0–3 composite films transducer (>100 MHz). The modeling results show that the Cubes model with a geometric factor n=0.05 fits well with the measured data. This model will be helpful for developing the 0–3 composite systems for ultrahigh frequency ultrasonic transducer design. [ABSTRACT FROM AUTHOR]

In this paper, we report the synthesis of g-C3N4-TiO2 hybrid photocatalyst by using the simple, cost-effective and eco-friendly process. The development of TiO2 nanoflakes on the surface of g-C3N4 nanosheet was carried out by the in situ sol–gel method. The XRD patterns reveal the anatase phase of TiO2 in the g-C3N4-TiO2 nanocomposite. HR-TEM images confirm the size of the nanoflakes in the range of 15–25 nm. The O–Ti and Ti–O–Ti bridge produces the absorption band from 560 to 710 cm−1 for TiO2; it is due to stretching vibrations and the specific band at 805 cm−1 marks the sym-triazine ring of g-C3N4. UV–Vis spectra show a redshift from 394 to 471 nm in the nanocomposite concerning a decrease in band gap. From BET, it is seen that the surface area of bare TiO2 and g-C3N4-TiO2 are 66 and 146 m2g−1, respectively. The nanoflakes morphology of g-C3N4-TiO2 was confirmed from FE-SEM images. The EDS spectrum confirms C, N, Ti, and O elements which prove the purity of the nanocomposite. The g-C3N4-TiO2 (1:4) acquired a noticeable enhancement of photocatalytic activity which is double for methyl orange degradation than TiO2. [ABSTRACT FROM AUTHOR]

In this paper, Fe-doping TiO2 was introduced into a dielectric barrier discharge (DBD) process for catalytic nonthermal plasma (NTP) degradation of a mode organic pollutant reactive blue (KN-R). Plasma was generated in a DBD reactor; Fe-doping TiO2 was prepared by the sol-gel process. The catalytic-NTP oxidation reactions were studied under various conditions including the examination of the effects of initial pH, KN-R concentrations, and catalyst dose. Typical results indicated the synergy between plasma excitation of KN-R followed by the catalytic action of Fe-doping TiO2, which not only improved the conversion but also increased the mineralization efficiency. The determination of hydrogen peroxide and nitrate ions, and ultraviolet–visible absorption and Fourier transform infrared spectra analyses revealed that catalysts in a plasma system strengthen the mineralization of KN-R. [ABSTRACT FROM PUBLISHER]

High-performance ultraviolet (UV) Schottky photodiodes obtained by growing Pd Schottky contacts on the sol-gel-derived n-ZnO thin films deposited on n-Si substrates have been reported in this paper. The current-voltage ( I – V ) measurements of the as-fabricated Schottky photodiodes show an excellent room temperature contrast ratio (i.e., the ratio of the current under UV illumination to the dark current) of \sim 5.332\times 10^3 and responsivity (i.e., the parameter characterizing the sensitivity of the device to the UV light) of \sim 8.39 A/W at −5 V reverse bias voltage, respectively; when the device is illuminated by an UV source of \sim 650~\mu \textW output power at $\sim 365$ nm. The measured room temperature contrast ratio and responsivity are believed to be the highest among the reported values in the literature for ZnO thin film-based Schottky photodiodes using sol-gel method. [ABSTRACT FROM AUTHOR]

The (Pd, Fe)-modified SnO2 (S1) and Pt-loaded SnO2 (S2) are synthesized via a sol-gel method. As S1 has better selectivity to CO against H2 while S2 to H2 against CO at 400 °C. Thus S1 and S2 can be used to detect the concentration of CO and H2, respectively. However, neither S1 nor S2 can detect the concentration of CO and H2 when they coexist. In this paper, S1 and S2 sensors are used simultaneously for mixed gas of CO and H2 detection, and the respective concentration of CO and H2 is calculated. The calculation process is explained as follows: the response of S1 (R1) and S2 (R2) to a fixed concentration of mixed gas of CO and H2 is obtained in experiment, respectively. So we can calculate the concentration of CO and H2 by using simultaneous equations with the independent variable R1 and R2. Contrast real values with calculated values of CO and H2 concentration, the error margin are all less than 5%, which indicates that this method may be a promising candidate for enhancing the selectivity of semiconductor-based gas sensor to two or more gases. [ABSTRACT FROM AUTHOR]

In this paper, a thorough study is dedicated to the manipulating of nanostructured zirconia thin films prepared by a sol-gel process with the focus on the wetting properties. It is observed that by engineering the amount of cetyltrimethylammonium bromide [[N(CH3)3] Br] (CTAB) and polyethylene glycol (PEG) in zirconium chloride precursor solution, the novel agar-like morphology with random orientation can be grown. Different morphologies are observed by changing the amount of PEG in the solution. All the prepared samples in this method show tetragonal phase after annealing at 500 °C for 1 h. The crystallite sizes have a direct correlation with the ratio of lattice parameters. The optical band gap is estimated by Kubelka-Munk method. Modified ZrO2 thin films at an optimum ratio of PEG to CTAB annealed at 500 °C and present water contact angle lower than 3° (without UV illumination) which indicates their superhydrophilic properties. The analytical results of SEM images of samples annealed at 500 °C are also reported. Spreading and wicking of liquid through the nanochannels which are formed in the vacant spaces between nanorods lead to superior wetting property. Annealing temperature also strongly affects the wettability of agar-like zirconia thin films. Agar-like ZrO2 thin films are obtained with superhydrophilic behavior by annealing at 500 °C. Similar agar-like morphology is also observed with hydrophobic character by annealing at 200 °C. The introduced preparation method in this paper provides an easy route to fabricate superhydrophilic agar-like ZrO2 thin films without further processing. [ABSTRACT FROM AUTHOR]

In this paper, the crystal orientations of Pb(Zr0.52Ti0.48)O3 (PZT) thin films prepared by sol-gel method were investigated by using various initial annealing temperature in the modified annealing process. The films were put directly into the muffle furnace when the temperature reached at 300-500 °C, it’s clear that this modified annealing process made the PZT films presented better (111)-orientation. A PtxPb intermetallic metastable phase was observed by X-ray diffraction, which is considered to be connected with the promotion of the (111) preferred orientation. The PZT thin film with 400 °C initial annealing temperature has the maximum (111) diffraction intensity, remanent polarization and dielectric constant. [ABSTRACT FROM AUTHOR]

This paper presents a new preparation method of SiO2 and Al2O3via a sol–gel route with CO2 as a pH regulator. The influence of carbon dioxide as a pH moderator on the textural parameters is demonstrated. The properties of the oxide xerogels were investigated using SEM, TEM, FT-IR, thermal analysis techniques, and low temperature nitrogen adsorption measurements to describe their structural evolution. The results illustrate differences in the final textural properties of the systems obtained depending on the pH regulator used in the synthesis. The method proposed is doubly beneficial as it eliminates the use of (organic or inorganic) acids and represents an interesting and new application of carbon dioxide. [ABSTRACT FROM AUTHOR]

This paper reports the coexistence of room-temperature ferroelectricity and ferromagnetism in double perovskite Bi2CoMnO6 ceramics synthesized by using the sol–gel combustion technique. X-ray diffraction analysis shows that the pure phase formation of Bi2CoMnO6 takes place in the sample calcined at 600 °C. XRD data is refined using Rietveld analysis. The morphology of the as-prepared ceramics was studied using SEM micrographs. The origin of multiferroic configuration in this compound is due to coupling of the long-range electric field of Bi 6s2 lone pair electrons with long-range spin order of Co–O–Mn, Co–O–Co and Mn–O–Mn orbitals. Ferroelectricity is also confirmed by positive-up and negative-down measurements. A remanent magnetization of Mr 7.4 × 10−3 emu/g and remanent polarization 2Pr = 0.33 μC/cm2 were observed. [ABSTRACT FROM AUTHOR]

This paper describes the fabrication of heteromorphic microlens arrays in the polymethyl methacrylate/titanium/organically modified siloxanes photosensitive hybrid films by UV nanoimprint technique and the applications of the prepared microlens arrays on the organic light-emitting diode. The hybrid films were obtained by combining a sol–gel technique and spin coating method. UV–visible spectroscopy and atomic force microscope are used to characterize the properties of the hybrid films, and the results indicate that the hybrid films have high transmittance and small surface roughness. Scanning electron microscope and surface profile results show that the heteromorphic microlens arrays formed in the hybrid films are uniform and well defined. Optical microscopy results show that the hexagonal microlens arrays have the relatively strong focusing ability and excellent imaging performance. Finally, the microlens arrays are applied to the organic light-emitting diode, the luminous properties of the organic light-emitting diode is enhanced, and there is a maximum improvement of about 43.9% in current efficiency for OLEDs with hexagonal microlens arrays. All the results above indicate that it is a simple and low-cost process to fabricate hybrid film microlens arrays by UV nanoimprint technique, and the prepared microlens arrays have potential applications in the organic light-emitting diode. [ABSTRACT FROM AUTHOR]

This paper demonstrates write-once-read-many-times (WORM) behavior of an Ag/CuO/n+-Si memory device. The CuO resistive switching layer with a thickness of 9.7 nm was prepared using a sol–gel process. The device shows a low conduction current of 10−10 A at a read voltage of 1 V. A sudden current increase is observed when the voltage increases to ∼3 V, corresponding to a resistance switching from a high-resistance state (HRS) to a low-resistance state (LRS). After that, the device remains in the LRS. Degradation of the HRS and the LRS is not observed for 104 read cycles. The HRS/LRS resistance ratio is 106, and the data retention time is over 105 s. The abrupt current increase cannot be triggered by a negative bias. The formation of Ag conductive bridges in the CuO layer is responsible for the resistance switching. Statistical analyses are performed to study the distributions of the set voltages and the resistances in the HRS and LRS. The effect of the compliance current on the operating current of the Ag/CuO/n+-Si WORM memory is also investigated. The carrier transport mechanisms are found to be dominated by Schottky emission, Ohmic, and SCLC conductions. The energy barrier is 1.066 eV, which is extracted by Schottky emission analysis. [ABSTRACT FROM AUTHOR]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The effects of annealing temperature on properties of YBCO films deposited on (100) LaAlO3 single crystal substrates derived from a water-based sol-gel process were investigated. In this paper, the in-plane texture is improved at higher temperatures but the out-of-plane texture follows an opposite trend. YBCO films annealed at 789 °C with homogeneous and smooth surface as well as Jc = 1. 7 MA/ cm² at 77 K and 0 T was obtained. Particles and holes observed on the other films could result in bad connections between superconducting grains and decrease the superconducting current in the films. Strain in these films is likely to enhance the pinning force and improve the transport properties under applied field. [ABSTRACT FROM AUTHOR]

In this paper, undoped and Pb-doped ZnO thin films have been prepared by sol gel method and deposited on glass substrate using dip-coating technique. The structural, morphological, and optical properties of the films were investigated as a function of Pb doping. The results of the structural tests showed that these films are of a polycrystalline hexagonal structure with a preferred orientation in the (002) direction. The grain size values of Pb-doped films were lower than that of pure ZnO, but the strain and the dislocation density values inecrease with increase Pb doping ratio. The atomic force microscopy (AFM) images showed that the particle size and Root Mean Square (RMS) of ZnO decrease with increasing Pb doping. The optical band gap values were found to increase from (3.19 to 3.30 eV) and the Urbach energy decrease from (322 to 313 meV). PL spectra exhibit an increased amount of defects with increasing Pb, which leads to a red shift in the UV region. [ABSTRACT FROM AUTHOR]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

CaO-doped γ-Al2O3 beads were prepared by an alginate assisted sol–gel method, followed by grafting with alkyl groups and impregnation of NbCl5 to construct multi-functionalized γ-Al2O3 beads for efficient catalytic conversion of glucose to 5-hydroxymethylfurfural (5-HMF). Doping with CaO improved the binding capacity of the catalyst with glucose and increased the Lewis acid amount. However, a high CaO content would cover the Lewis acid sites of γ-Al2O3, resulting in a lower isomeric conversion of glucose to fructose. When the C8–Ca(10%)–γ-Al2O3 catalyst was loaded with Nb2O5, intermediate fructose was consumed rapidly resulting in complete conversion of glucose, which indicated that conversion of glucose to 5-HMF involved the isomeric conversion of glucose to fructose followed by dehydration of fructose to 5-HMF. This was necessary to balance hydrophilic isomerization reactions with restraining the rehydration of 5-HMF by hydrophobic modification. This is similar to the reaction in which a medium with a certain amount of water was beneficial for glucose isomerization. Under the synergistic effect of Lewis acid provided by γ-Al2O3 and Brønsted acid offered by Nb2O5, C8–Ca(10%)–γ-Al2O3–Nb(3%), a glucose conversation rate of 100% and the highest yield of 5-HMF (68.4%) were achieved in the reaction medium with a dimethylsulfoxide/H2O (V/V) ratio of 4 : 1, a catalyst amount of 33 mg, a reaction temperature of 140 °C and a reaction time of 4 h. [ABSTRACT FROM AUTHOR]

Spinel materials are gradually becoming high infrared radiation materials with the most potential because of their special crystal structure. However, it is still difficult to design the microstructure reasonably and synthesize it at low temperature. In this paper, the honeycomb-like CuMn 2 O 4 spinels were prepared via a facile sol-gel method with a subsequent low-temperature sintering treatment. Therefore, the CMO samples with numerous pores are conducive to improving absorptivity and emissivity. Moreover, the optimum experimental conditions for high infrared emissivity were acquired by detailed investigation of the synthesis parameters including the molar ratio of trimonium citrate to metal ions, the molar ratio of urea to metal ions and the sintering temperature. Under the synergistic effect of internal factors such as, a suitable amount of impurities, abundant oxygen vacancy, small band gap, and good crystallinity, the obtained sample CMO-800 achieved excellent infrared radiation performance. Its infrared emissivity values at the test temperature of 30 °C and 600 °C separately reached 0.801 and 0.965 in the wavelength range of 3–5 μm. More significantly, this work provides significant guidance for the design and preparation of spinel materials with excellent infrared emissivity. [ABSTRACT FROM AUTHOR]

Current commercial lithium ion battery (LIB) anodes comprising graphite and Li4Ti5O12 inevitably suffer from safety risk and low energy density. Hence, a novel anode material of Ti0.95Nb0.95O4/C hybrid nanotubes was developed via a modified sol-gel method combined with subsequent calcination. The hybrids consist of Ti0.95Nb0.95O4 quantum dots that are homogeneously embedded in the walls of porous bamboo-like CNTs. The high capacity feature of multiple redox couples of Ti-Nb-O based anodes is demonstrated by ex situ XPS in the hybrids. With the advantages of stimulative lithium storage, increased conductivity and robust mechanical properties due to the unique hybrid structure, the hybrids exhibit a high capacity (516.8 mA h g-1 at 0.2 A g-1), superior long-term cycling stability (142.7 mA h g-1 at 5 A g-1 after 3000 cycles) and an ultra-high rate capability (234.6 mA h g-1 at 1 A g-1 and 125 mA h g-1 at 8 A g-1). Meanwhile, the hybrids showed superior electrochemical performance compared with the reported Li4Ti5O12 and Ti-Nb-O based anodes. Furthermore, the GITT measurements revealed the fast Li+ transport for the charge-discharge processes of the hybrids. Such prominent merits of the Ti0.95Nb0.95O4/C hybrid nanotubes make them more likely candidates that can replace graphite and Li4Ti5O12 anodes in LIBs. [ABSTRACT FROM AUTHOR]

In this paper, LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NMC811) thin films were prepared by the sol-gel method based on different parameter conditions, and the microstructure and electrochemical properties of the films were compared to obtain the film sample under the best preparation parameters. In order to explain the formation mechanism of cell battery performance based on the NMC811 cathode at the nano scale, electrochemical strain microscopy, conductive atomic force microscopy and Kelvin probe force microscopy are specifically utilized to study the changes of NMC811 thin film in electrochemical deformation, conductivity, and potential distribution under different electrical and thermal fields. The results indicate that the local amplitude, conductivity, and electrical potential of thin film in the scanning region increases with the voltage from 0 V to 3 V and the temperature from 25 °C to 150 °C. However, the electrochemical deformation, conductivity, and potential of the film decrease significantly when the voltage is applied to 4 V or the temperature rises to 200 °C. These results provide visual evidence for the influence of external field on the phase structure change and lithium-ion diffusion behavior of NMC811 thin film. [ABSTRACT FROM AUTHOR]

In this study, CoSb3 and Ba filled CoSb3 skutterudites are synthesized by a convenient self-reduction sol–gel method using a mixed-acid (citric acid & oxalic acid) as a coordination and reduction agent at 500 °C in N2. The influence of the mixed-acid ratio and the heat treatment conditions on the sample phases is discussed. The results show that single phase BaxCoSb3 (0 ≤ x ≤ 0.15) are synthesized successfully at 500 °C for 30 min in N2, and a ratio from 3 : 1 to 5 : 1 for citric acid/oxalic acid is necessary. The reaction mechanism can be described as the citric acid coordinating well with Co2+ and Sb3+ and producing a stable gel, while oxalic acid plays a role in tight binding and fully reducing particles in the reaction system. Furthermore, the maximal filling fraction of Ba filled CoSb3 is 0.15 in this sol–gel method, which is slightly higher than that of Ba0.51Co4Sb12 synthesized by the high pressure synthesis method. [ABSTRACT FROM AUTHOR]

An easy and effective method to prepare superhydrophobic thin film has been developed. The film with optically transparent and low refractive index was composed by one-step coating with modified silica nanoparticles. The silica nanoparticles were prepared by sol-gel process of hydrolysis and condensation of alkoxysilane compounds and then surface modification silica nanoparticles, 50 ± 10 nm, were accomplished using methoxytrimethylsilane (MOTMS). Water contact angle of film increased with the weight of MOTMS of silica sol. When the weight of MOTMS was optimized, the water contact angle and sliding angle of film were 152.8° and less than 10°, respectively. The transmittance of film was also increased as compared to the un-coated microscope glass slide, from 91 to 93.5 %. The refractive index of the film was approximately 1.09 as measured by ellipsometer. The superhydrphobic thin film was also successfully made by using spray coating and the water contact angle of this film was more than 160°. Surface morphology of difference coating methods, dip and spray, were studied. Our result suggests that the film can be applied for superhydrophobicity and optical applications. [ABSTRACT FROM AUTHOR]

In this paper, we report the synthesis, phase formation, and basic characterization of polycrystalline Bi2Fe4O9, Bi1.98Ba0.02Fe4O9, and Bi1.98Ce0.02Fe4O9 samples prepared by the sol-gel technique. The crystal structure of the prepared samples has been characterized by means of X-ray diffraction and Raman scattering spectroscopy. All the obtained XRD peaks can be indexed to the orthorhombic Pbam structure and reveal the formation of Bi2Fe4O9. The Raman spectrum identifies Ag, B2g, and B3g active optical phonon modes. The crystallite size and morphology of the nanoparticles have been analyzed using scanning electron microscope (SEM). Dielectric constant (ε′) decreases as the frequency increases, and it is constant at the higher frequency region which can be explained based on the ionic conduction phenomenon in the low frequency region. The ε′ values of Bi2Fe4O9(650–850), Bi2Fe4O9(800–850), Bi1.98Ba0.02Fe4O9, and Bi1.98Ce0.02Fe4O9 samples at 10 Hz frequency are about 37, 75, 90, and 393, respectively. The observed properties signify that these materials are very useful in advanced technological and practical applications. [ABSTRACT FROM AUTHOR]

In this paper, the boron‐containing mesoporous bioactive glass (MBG) nanospheres have been successfully synthesized by modified sol‐gel method assisted by surfactant, and the effect of boron substitution on structure and bioactivity was evaluated by combining experiments and ab initio molecular dynamics (AIMD) simulations. All of the samples exhibit regularly uniform mesoporous spherical microstructure with an average size of about 60 nm, and the boron‐containing MBGs show higher specific surface area with the value up to 416.20 m2/g. The simulated body fluid (SBF) immersion test confirms that the deposited hydroxyapatite (HA) evidently increases with the increasing of boron content, indicating that the biological behavior has been significantly improved resulting from incorporation of boron. Additionally, our results also reveal that B2O3 substitution has positive impact on cell proliferation of human periodontal ligament cells (hPDLCs) at lower extracted concentration. Furthermore, AIMD simulation is employed to understand the relationship between structural changes and in vitro bioactivity in terms of structural information, especially the boron coordination number. The results illustrate that the boron‐containing MBG nanospheres with excellent bioactivity are great potential for biomedical applications. [ABSTRACT FROM AUTHOR]

The effect of Cerium on the properties of the multi-functional SiO2 -TiO2:Ce3+ nanocomposite films are shown in this paper. The multi-functional SiO2-TiO2:Ce3+ nanocomposite film was synthesis by a sol-gel method and coated several layers on a glass substrate by a spin-coating technique. The bonding was indicated in the obtained film that Si-O-Si and Si-O-Ti bonding, which are characteristics that bonding in the SiO2-TiO2 matrix by the FT-IR spectrum. The TiO2 crystal in the anatase phase and SiO2 in the amorphous phase of the nanocomposite film was determined by X-ray Diffraction. When increased doping of Ce3+, the prepared films have a high transmittance in the visible light (from 84.5 to 88.3%, 400 - 800 nm), the red-shifted of the absorbance edge in UV(A) region (from 355 to 390 nm), and the optical bandgap is narrowed. Particularly, the SiO2-TiO2:6%Ce3+ film has the transmittance by 88.3% in the visible light (400 - 800 nm), absorbance in the UV(A) light (390 nm), and performance the super-hydrophilic with/without thermal and UV(A) light. Thus, the multi-functional SiO2-TiO2:6%Ce3+ nanocomposite film could have a potential to use as the protective high transmittance film to avoid the UV-A light and exhibits a super-hydrophilic on the material surface such as glasses, photovoltaic devices, window panels. [ABSTRACT FROM AUTHOR]

The high degradation rate limits the clinical applications of calcium silicate bioceramics. In this paper, Ca2MgSi2O7 and Ca2ZnSi2O7 were successfully prepared using sol-gel method by incorporating magnesium and zinc into Ca–Si-based system. The results showed that the obtained ceramics presented the macroporous structure and the incorporation of zinc obviously reduced the samples specific surface area. Compared with CaSiO3 (24.8%), the weight loss of Ca2ZnSi2O7 was the lowest (8.4%) and Ca2MgSi2O7 was the middle (12.1%) after 28 days soaking in Tris-HCl buffers. Meanwhile, the formation of apatite was also confirmed after soaking in SBF. Through above investigations, the incorporation of magnesium and zinc should be one of the effective ways to adjust the degradation and apatite formation of Ca–Si-based bioceramics, which would meet the various clinical demands. [ABSTRACT FROM AUTHOR]

Ga- doped ZnO films and Ga-Al co - doped ZnO films were prepared on glass and Si substrates by sol - gel spin coating. The crystal structure of the sample film was characterized by X-ray diffractometer (XRD), the surface morphology of the film was measured by scanning electron microscope (SEM), the optical properties were investigated by UV-vis spectrophotometer, and the luminescence properties were analyzed by photoluminescence spectrum (PL spectrum).In the experiment on the effect of Ga doping amount on ZnO thin film, Ga doping did not change the structure of ZnO hexagonal wurtzite. A proper amount of Ga will make the grain of the film grow optimally along the c-axis, the grain size becomes smaller, and the film surface becomes smoother and smoother. When Ga doping amount is 3 at%, the film has the best preferred orientation, the most uniform grain growth, and the highest transmittance in the visible region. The effect of Al doping amount on Ga-Al co—doped ZnO thin films was investigated in this paper. The doping amount of Ga was controlled as 3at%, and the doping amount of Al was 0.5 at%, 1.0 at%, 1.5 at%, 2.0 at%, and 2.5 at%. It was found that the addition of an appropriate amount of Al ion would make the grain grow along the horizontal direction, reduce the grain gap on the surface of the film, make the surface smooth and smooth, and improve the crystallization and optical properties of the film. When Ga doping amount is 3.0 at% and Al doping amount is 2.0 at%, the average transmittance of the film in the visible light region is the highest (92%) and the forbidden band width is the largest (about 3.95 ev). At this time, the near-band emission peak of the film is the strongest and the defect luminescence peak is the weakest. [ABSTRACT FROM AUTHOR]