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  • Tailoring the luminescent properties of Ca 9 La(PO 4 ) 5 (SiO 4 )F 2 :1 mol%Eu 3+ phosphor via doping of chloride, molybdate, vanadate, sulfate, and tungstate ions
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-21
    Chaitali M. Mehare, Yatish R. Parauha, Vibha Chopra, Sudeshna Ray, N. S. Dhoble, Chandan Ghanty, S. J. Dhoble

    Abstract We report here, the Ca9La(PO4)5(SiO4)F2:1 mol%Eu3+ phosphor via doping of chloride, molybdate, vanadate, sulfate, and tungstate ions that were synthesized by high-temperature solid-state reaction method. The phase formation was confirmed by X-ray diffraction (XRD) measurements. Morphological studies were performed using scanning electron microscopy. Photoluminescence and thermoluminescence properties of the synthesized phosphors were systematically studied. The PL excitation spectra of host material show peaks at 395 nm and 466 nm corresponding to 7F0 → 5L6 and 7F0 → 5D2 transitions of Eu3+, respectively. Further photoluminescence properties also studied after doping of molybdate, vanadate, sulfate, and tungstate ions in host material. When excited at 395 nm and 466 nm, PL emission spectra show emission band at around 595 nm and 616 nm, which attributes to 5D0 → 7F1 and 5D0 → 7F2 transitions, respectively. Further TL glow curves of all the synthesized phosphors were studied when exposed to γ-rays.

    更新日期:2020-01-22
  • Frequency selective absorbing property of nanoring-shaped polyaniline with broadband absorption
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-21
    Yunan Shi, Jiali Chen, Ji Dai, Jun Qiu

    Abstract Frequency selective absorbing property (FSAP) is a key to realize radar frequency selective surfaces' stealth technology, which has great application prospects in national military industry. Different from traditional metal materials, herein, through the design of polyaniline microstructure as well as doping modification of the polymerization, polyaniline nanorings (PANI NRs) with certain electrical conductivity have been constructed. By constructing nanoring-shaped morphology, PANI NRs achieve strong reflection and great absorption of electromagnetic waves (EMWs) in different frequency ranges. These two properties are vital for realizing high-efficient FSAP. PANI NRs demonstrate negative permittivity within 50–1000 MHz frequency range where they can show strong EMWs reflection, and the negative permittivity is attributed to the plasma-like behavior of conductive network formed by plenty of overlapping nanorings. In addition, this porous structure also contributes to increase reflection and refraction of incident EMWs and then continuously consuming their energy, ensuring outstanding EMWs absorption property during 2–18 GHz frequency bandwidth.

    更新日期:2020-01-22
  • Synthesis, characterization, magnetic and antimicrobial properties of silver chromite nanoparticles
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-21
    Asmaa A. H. El-Bassuony, H. K. Abdelsalam

    Abstract A novel nanostructured silver chromite with the chemical formula Ag2Cr2O4 was synthesized at 400 °C by simple, cost effective, flash auto-combustion method. The average crystallite size was found to be 76.6 nm by crystallographic study of X-ray analysis (XRD) which also showed single-phase formation with spinel cubic structure. The formation of the sample was assured by measuring the Fourier transform infrared (FTIR) spectrum and the elemental study using energy dispersive X-ray (EDX) measurement. The field emission scanning electron microscopy (FESEM) and the atomic force microscopy (AFM) were studied which showed a spherical interlinked behavior with aggregations of the grains. The M–H curve showed an exchange bias which gave a slight horizontal shift in the curve. The obtained data extracted from the magnetic properties recommended the suitability of Ag2Cr2O4 nanoparticles to be applied in information storage devices, MRAM, and sensor devices. Moreover, this is the first study to synthesize and analyze the characterization and antimicrobial properties of Ag2Cr2O4 nanoparticles at 400 °C. A fascinating behavior appeared by studying the antimicrobial properties which gave a strong antibacterial efficacy against S. aureus and B. subtilis (G +) and also against P. aeruginosa (G −) bacterial species. Also, it gave a strong antifungal efficacy against A. flavus (Aspergillus) and C. albicans (Candida) fungal species. Thus, Ag2Cr2O4 nanoparticles at 400 °C could be an attractive and an alternative antifungal and antibacterial nanomaterial that open new paths for new alternative nanomaterial chemotherapy against different bacteria and fungi.

    更新日期:2020-01-22
  • Resistive- and capacitive-type humidity and temperature sensors based on a novel caged nickel sulfide for environmental monitoring
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-21
    Muneeb-ur-Rahman, Ghani Shah, Amir Ullah, Zia-ur-Rahman, Mehwish Arshad, Rajwali Khan, Zulfiqar, Burhan Ullah, Iftikhar Ahmad

    Abstract In this work for the first time, a new bis(4-benzylpiperazine-1-carbodithioato-k2S,Sʹ)nickel(II) complex (hereafter caged nickel sulfide) has been used to fabricate the capacitive-type and resistive-type sensor. The surface consisted of 2D plates, pores and pore-channels of various shapes and size. These 2D plates and pores played a pivotal role in the sensing mechanism of the sensor. The conduction mechanism is based on Von Grotthuss mechanism. In the relative humidity (RH) range 30–90%, the resistance of the sensor was decreased by two orders of magnitude (from 2.94 × 108 Ω at 30%RH to 2.34 × 106 Ω at 90%RH at operational frequency of 120 Hz). While at applied frequency of 120 Hz, capacitance of the sensor was increased from 15.95 pF to 38.1 pF in the range of 30–90%RH. At higher frequency (10 kHz) the capacitance of the sensor is reduced to 6.285 pF. The maximum hysteresis of 1.54% is noted which is less than the reported in the literature. The response and recovery time of the sensor were 25 and 30 s, respectively, which are either far smaller or greater than the response and recovery time of the various sensors reported in the literature.

    更新日期:2020-01-22
  • Multistate resistance switching in Bi/PMN–PT(111) heterostructures by electric and magnetic field
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-20
    Zhi-Xue Xu, Jian-Min Yan, Meng Xu, Hui Wang, Lei Guo, Guan-Yin Gao, Ren-Kui Zheng

    Abstract Bi thin films were grown on (111)-oriented 0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3 (PMN–PT) single-crystal substrates by pulsed laser deposition. Resistance of Bi/PMN–PT could be modulated by asymmetrical bipolar electric field in a reversible and nonvolatile manner at 300 K. By tuning asymmetrical bipolar electric field, different nonvolatile strain states could be generated in PMN–PT and transferred to Bi thin film, which leads to different nonvolatile resistance states. Furthermore, different resistance states of the Bi films could be achieved under different magnetic field at 300 K. The ferroelastic strain- and magnetic-field-modulated resistive properties in Bi/PMN–PT suggest a promising approach for multistate resistive memories.

    更新日期:2020-01-21
  • Heterostructure device based on Brilliant Green nanoparticles–PVA/p-Si interface for analog–digital converting dual-functional sensor applications
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-20
    Ahmed M. Nawar, Ahmed M. El-Mahalawy

    Abstract Owing to the growing development of electronics manufacturing in tandem with the need for integration of electronic devices in the smallest size available, the need for multifunctional detectors becomes an insisted demand. Hence, the present research reports the enhancement of the optical and photoelectrical properties of polyvinyl alcohol, PVA, in ultraviolet and visible light regions by incorporating brilliant green dye, BG, nanoparticles of particle size 67.5 nm in PVA matrix. The molecular and crystal structure studies of PVA-BG spin-coated films are performed for verification of the influence of the embedded BG-dye molecules in the PVA matrix. The surface morphology and roughness of PVA-BG films are inspected and revealed a smooth nature of the film with average roughness ~ 4.157 nm. Significant enhancement of PVA optical properties is detected after adding BG nanoparticles using UV–Vis–NIR spectrophotometry, where a strong absorption in the visible region has resulted. Four exciting transitions are estimated with energies ~ 1.69, 2.31, 2.96, 3.29 and 4.64 eV. These enhanced properties are exploited in fabricating MIS structure based on Ag/PVA-BG/p-Si/Al as a dual-functional detector for sensing temperature and light intensity. The sensitivity of fabricated architecture as a temperature sensor is examined in the temperature range (293–373 K) and achieved an optimized sensitivity ~ 6.67 mV/K with a coefficient of determination ~ 99.30801 at driving current ~ 100 μA. The performance of the fabricated device as a light sensor is examined under the influence of halogen lamb light in light intensity range (20–80) mW/cm2. The performance evaluation of the fabricated device as a photodetector is examined in terms of spectral responsivity, specific detectivity, linear dynamic range, signal-to-noise ratio, and ON/OFF switching behavior. The resulted values of these figures of merit parameters confirm the validity of Ag/PVA-BG/p-Si/Al to be utilized as a dual-functional sensor for light and temperature in many microelectronic circuits with stable, reliable and linear performance.

    更新日期:2020-01-21
  • Enhancement of photoluminescence properties of Y 0.95 (P 0.6 V 0.4 )O 4 :Eu 0.05 phosphors by doping Al 3+ ions
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-20
    Shakir Ullah, Yuanquan Feng, Chao Dou, Shijia Sun, Huilin Kong, Fei Zheng, Jie Tang, Degao Zhong, Bing Teng

    Abstract This paper reports an approach for improving the photoluminescence characteristics of red-emitting Y0.95(P0.6V0.4)O4:Eu0.05 phosphors, with the incorporation of Al3+ ions, using a chemical co-precipitation process. In this paper, structural, scanning electron microscopic (SEM), photoluminescence properties, infrared spectroscopy, and CIE of the Y0.95−x(P0.6V0.4)AlxO4:Eu0.05 (x = 0.0, 0.005, 0.01, 0.015, 0.02, 0.025, 0.03, 0.035) phosphors are reported. The doping of a small amount of Al3+ ions to Y0.95−x(P0.6V0.4)AlxO4:Eu0.05 phosphors significantly enhanced the emission intensity up to x = 0.025%. The most dominant red emission intensity peak of Eu3+ for 5D0 → 7F2 transition of the Y0.975(P0.6V0.4)Al0.025O4:Eu0.05 phosphor is located at 622 nm, which is stronger than that of the free Al3+ Y0.95(P0.6V0.4)O4:Eu0.05 phosphor. The result shows that this phosphor has a certain amount of the application prospect of the white LED.

    更新日期:2020-01-21
  • Photocatalytic degradation of 2,4-dichlorophenol on ZrO 2 –TiO 2 : influence of crystal size, surface area, and energetic states
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-20
    Diana Guerrero-Araque, David Ramírez-Ortega, Próspero Acevedo-Peña, Rodolfo Zanella, Ricardo Gómez

    Abstract ZrO2–TiO2 heterostructure with 5 mol% of ZrO2 was synthesized by the sol–gel method and calcined at different temperatures (300–600 °C). The photocatalysts were characterized by thermal analysis, X-ray diffraction, physisorption of N2, diffuse reflectance spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. The photocatalytic activity was tested for the removal of 2,4-dichlorophenol under ultraviolet irradiation, being the materials exhibiting the best performance those calcined at 400 °C and 500 °C with 99% and 98% of degradation, respectively, after 150 min under irradiation. This behavior was related to a smaller crystallite size, higher surface area, and significant hydroxyl radicals produced. The (photo)electrochemical study showed that temperatures of 400 °C and 500 °C also generated an optimum amount of energetic states that act as electron traps and decrease the electron–hole pair recombination, favoring the oxidation of 2,4-dichlorophenol. However, at 300 °C and 600 °C, these energetic states act as an energy barrier that reduces the effective charge transfer and therefore decreases the photocatalytic activity of the materials.

    更新日期:2020-01-21
  • Regulation of Ni–Si intermetallics in Cu–Ni–Si alloys and its influence on electrical breakdown properties
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-20
    Hui Xie, Lei Jia, Shiping Tao, Xin Wei, ZhenLin Lu

    Abstract Microstructure of Cu–Ni–Si alloys, especially morphology, amount and size of Ni–Si intermetallics, was controlled by heat and thermal–mechanical treatment, and then its influence on electrical breakdown behavior was investigated systematically. Results show that first breakdown is prior to occur on the Ni3Si phase at the grain boundary and δ-Ni2Si in the inner of Cu matrix in Cu–Ni–Si alloys. The decrease of Ni3Si size by using thermal–mechanical treatment can significant enhance the breakdown behavior of Cu–Ni–Si alloys since it can change the total area of preferred phase within the action area of cathode spot. As a result, the chopping current and erosion depth decrease but arc life, breakdown field and erosion area increase with the decrease of Ni3Si size, while the precipitation δ-Ni2Si phase has limited effect on breakdown properties. On the whole, Cu–Ni–Si alloy by solution, hot forging and aging treatments in sequence has the best breakdown properties due to the uniform dispersion of Ni3Si phase.

    更新日期:2020-01-21
  • Novel hyper branched polyaniline nanocomposites for gamma radiation dosimetry
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-20
    Noha Elhalawany, Ahmed R. Wassel, Ahmed E. Abdelhamid, Azza Abou Elfadl, Samir Nouh

    Abstract Novel hyperbranched poly aniline nanocomposites have been successfully prepared. Aniline monomer has been polymerized in presence of Mn+2 ions and/or mixed Mn+2/Zn+2 ions under high shearing effect homogenizer at 10,000 rpm. The prepared nanocomposites have been characterized via scanning electron microscopy SEM, transmission electron microscopy TEM, UV–Visible spectrometry UV–VIS, gel permeation chromatography GPC, Fourier transform infrared spectroscopy FT-IR and thermo gravimetric analysis TGA. The morphological studies revealed that the nanocomposites have superior morphologies and are highly branched. The optical as well as electrical properties of the formed nanocomposites have been investigated. The ac conductivity measurements showed that the conductivities of the prepared nanocomposites are frequency dependent and follow up hopping conduction mechanism. Furthermore, the formed nanocomposites in the form of powder have been incorporated into polymethyl methacrylate PMMA matrix to form transparent sheets or films with light green color for dosimetric applications. The formed sheets or films have been exposed to different gamma radiation doses ranging from 20 to 200 kGy. Upon irradiation by different doses, the films showed visually a change in color and became darker. These color changes have been measured via UV–VIS spectrometry in transmission mode as a function of gamma irradiation dose. Structural changes upon irradiation have been also investigated via X-ray diffraction as a function of gamma radiation dose. As far as we know, these novel highly branched PANI nanocomposites have not been reported yet in the open literature nor their applications in the field of gamma radiation dosimetry.

    更新日期:2020-01-21
  • Influence of double current injection annealing on anti-LID effect in mono-like cast silicon PERC solar cells
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-20
    Zehui Wang, Honglie Shen, Dongli Hu, Qingzhu Wei, Zhichun Ni, Yufang Li, Luanhong Sun, Hongqiang Qian

    Abstract Mono-like cast silicon (ML C-Si) passivated emitter and rear cell (PERC) solar cells with high performance and low price are becoming popular in the modern PV market. In this work, mono-like cast silicon PERC solar cells with B and Ga co-doping were treated by single current injection annealing (CIA) process and double CIA process. According to Light-induced degradation (LID) effect analysis, it was found that both single CIA process and double CIA process would enhance the electrical properties of the solar cells. After a light soaking treatment for 60 kWh, the efficiency of the solar cells treated by single CIA process decreased by 1.96% comparing with that before the CIA process. In contrast, the efficiency of the solar cells treated by double CIA process decreased by only 1.13%. All the results, including changes in other electrical properties of solar cells, showed that double CIA process would effectively enhance the anti-LID effect of ML C-Si PERC solar cells.

    更新日期:2020-01-21
  • Gd-doped soft Mn–Zn nanoferrites: synthesis, microstructural, magnetic and dielectric characterizations
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-20
    Kamar Tanbir, Mritunjoy Prasad Ghosh, Rakesh Kumar Singh, Samrat Mukherjee

    Abstract Nanocrystalline Gd-doped soft Mn–Zn spinel ferrites with a generic formula Mn0.5Zn0.5Fe2−xGdxO4 (x = 0.00, 0.04, 0.08 and 0.12) were synthesized using standard chemical co-precipitation technique. The powder X-ray diffractograms confirmed the phase purity of all the prepared samples along with average crystallite sizes in the range of 3 ± 1 nm. All the prepared nanoferrites displayed superparamagnetic behavior at room temperature as ensured by the room temperature hysteresis curves. The Néel temperature of all the prepared nanoferrites were below 50 K as seen from the M(T) curves. The indirect optical band gaps for all the Gd-doped nanoferrites were found in the range of 1.86 ± 0.02 eV. The variation of AC conductivity with applied electric field frequencies revealed that the hopping of electrons is the charge conduction mechanism of the nanoferrites.

    更新日期:2020-01-21
  • Dielectric characteristics of La(Mg 0.5−x Ni x Sn 0.5 )O 3 ceramics at microwave frequency for application in sub-6 GHz patch array antenna
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-20
    Yih-Chien Chen, Yu-Cheng You

    Abstract The series of La(Mg0.5−xNixSn0.5)O3 microwave ceramics were investigated for application in sub-6 GHz patch array antenna. The microwave dielectric characteristics of La(Mg0.5−xNixSn0.5)O3 ceramics are determined using X-ray diffraction patterns, Rietveld refinement, and Raman spectra. As the degree of substitution of Ni2+ increases, the position of the A1g(O) Raman mode shifts toward a higher frequency. The La(Mg0.45Ni0.05Sn0.5)O3 exhibits a minimum full width at half maximum for the A1g(O) Raman vibration mode. At x = 0.05, a permittivity of 19.8 and a quality factor (Q × f) of 104,000 GHz were achieved with a temperature coefficient at the resonant frequency (TCF) of − 87.9 ppm/°C. The proposed sub-6 GHz 2 × 2 patch array antenna has frequencies cover sub-6 GHz band, LTE band 42, and LTE band 43. A 10 dB return loss with bandwidth 848 MHz (3114–3962 MHz) was successfully achieved.

    更新日期:2020-01-21
  • Synthesis and dielectric spectroscopic study of lead-free ferroelectric ceramic K 0.5 Bi 0.5 TiO 3 -NaNbO 3
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-20
    S. K. Mohanty, Debi Prasad Datta, B. Behera, Hari Sankar Mohanty, Biswajit Pati, Piyush R. Das

    Abstract We report the synthesis and promising electrical properties of a new lead-free ferroelectric ceramic K0.5Bi0.5TiO3-NaNbO3 (KBT-NN), which can be a candidate of choice for future sensors, FeRAM etc. Mixed-oxide method has been employed to prepare the compound comprising of uniformly distributed grains. Detailed structural analysis revealed its orthorhombic structure with space group Pmc21. In-depth analysis of the electrical characterization data revealed a band-gap of 3.11 eV and presence of defects in the bands. Further, ferroelectric phase transition is observed to occur at 395 °C. The dielectric properties of the material, investigated over a wide range of frequencies and temperatures, indicate that its ac conductivity depends upon frequency according to Jonscher’s power law.

    更新日期:2020-01-21
  • Structure and microwave dielectric properties of BaAl 2−2x (CuSi) x Si 2 O 8 ceramics
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-20
    Xinkan Yan, Shihua Ding, Yun Zhang, Tianxiu Song, Long Huang, Xiaoyun Zhang

    Abstract The sintering behavior, phase composition, microstructure and dielectric properties of BaAl2−2x(CuSi)xSi2O8 (x = 0, 0.01, 0.015, 0.02, 0.04, 0.06, 0.08) ceramics prepared via solid-state reaction route were investigated. Deviation between theoretical and experimental permittivity of BaAl2Si2O8 ceramics was discussed, and the theoretical and experimental temperature coefficient of resonant frequency (τf) was also compared. The results showed that substituting (Cu0.5Si0.5)3+ for Al3+ in matrix of hexacelsian could lower the sintering temperature from 1400 to 1200 °C and greatly promote the transformation of hexacelsian-to-celsian. And the single celsian phase was obtained for the compositions with x ≥ 0.02. The bulk densities, microstructure and dielectric properties of BaAl2−2x(CuSi)xSi2O8 ceramics were improved by doping a small quantity of (Cu0.5Si0.5)3+ ions in the BaAl2Si2O8. The BaAl1.96(CuSi)0.02Si2O8 ceramics sintered at 1300 °C obtained good microwave dielectric properties: εr = 6.7, Q × f = 31,276 GHz, τf = − 17.17 × 10−6 °C−1.

    更新日期:2020-01-21
  • The structural, dielectric, and magnetic properties of GdMnO 3 multiferroic ceramics
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-20
    Fengjiao Ye, Haiyang Dai, Manman Wang, Jing Chen, Tao Li, Zhenping Chen

    Abstract GdMnO3 (GMO) ceramics were prepared by solid-state reaction method, the structure, defects, dielectric, and magnetic properties of GMO ceramics sintered at different temperatures have been studied. Characterization by XRD indicates that impurity phase-free GMO can be synthesized at 1350 °C. SEM measurements show that the grain size of GMO increases and the microstructure becomes denser with increasing sintering temperature. Positron annihilation results reveal that the vacancies concentration decreases when sintering temperature increases from 1300 to 1350 °C, and then increases when sintering temperature increases from 1350 to 1400 °C. Dielectric measurements indicate that the GMO ceramic sintered at 1350 °C presents higher dielectric constant and smaller dielectric loss. Magnetic properties measurements show that the magnetic properties of GMO can be modulated by sintering temperature. The relation between structure and properties implies that the cation vacancy defect has remarkable effects on the dielectric and magnetic properties of GMO.

    更新日期:2020-01-21
  • Highly bright and sensitive thermometric LiYF 4 :Yb, Er upconversion nanocrystals through Mg 2+ tridoping
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-20
    Xueshuang Deng, Meidong Yu, Xin Zhou, Zhetao Xia, Xiaohong Chen, Sumei Huang

    Abstract A new strategy is reported to enhance the upconversion (UC) luminescence emission of LiYF4:Yb, Er nanocrystals (NCs) using magnesium as a dopant. We carried out systematic experimental studies on the crystal structure, grain size, and UC emitting property of the tetragonal LiYF4:Yb, Er with varied concentrations of Mg2+. The UC luminescence properties were examined under 980 nm laser illumination with various excitation power densities. At a proper doping concentration, co-doping of Mg2+ ions into LiYF4:Yb, Er is found to result in efficient reinforcement in both the green and red upconverted emissions. Remarkably, the maximum green and red luminescence intensities were reinforced by sevenfold and fivefold, respectively, when 7 mol% Mg2+ was co-doped into tetragonal LiYF4. The possible origin and mechanism for boosting UC emission were explained according to the alteration of the cell volume and the local crystal field surrounding the Er3+ ions by co-doping of Mg2+. Moreover, the emission-optimized LiYF4 UCNCs were further investigated to understand thermal-sensing behaviors employing the fluorescence intensity ratio (FIR) approach from the two neighboring thermal coupled states (2H11/2/4S3/2). The optimization of Mg2+ co-doping in LiYF4:Yb, Er allowed the resultant UCNCs to be an excellent luminescent thermometer over a wide range of temperature. Applying the optimized UCNCs as an optical thermometer, a maximum thermal sensitivity (S) of 5.43 × 10–2 K−1 was achieved at room temperature and a low-power excited upconversion (1 W cm−2). The achieved S value is more advanced than most of the Er-based nanophosphors reported heretofore. This paper provides a perspective scheme to design and grow high-quality upconversion nanomaterials for achieving the preconditions of the pragmatic application in temperature sensing, optically heating, and color display devices.

    更新日期:2020-01-21
  • Effect of synthesis route on structural, morphological, Raman, dielectric, and electric properties of La 0.8 Ba 0.1 Bi 0.1 FeO 3
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-20
    E. M. Benali, A. Benali, M. Bejar, E. Dhahri, M. P. F. Graca, M. A. Valente, B. F. O. Costa

    Abstract Two compounds with the formula La0.8Ba0.1Bi0.1FeO3 have been prepared by the sol–gel (LBBFO-SG) and the auto-combustion (LBBFO-AC) preparation methods. The effect of the preparation method on structural, morphology, vibrational, electrical, and dielectric properties have been carried out using the X-ray diffraction (XRD), Scanning electron microscopy (SEM), and Raman and impedance spectroscopy. The Rietveld refinement of the XRD diffractograms confirms the crystallization of both compounds through the Pnma space group. Furthermore, the nano-size scale of the prepared compounds was verified by the XRD and the SEM microscopy. From the Raman study, we conclude that the vibration modes are similar to those of the pure LaFeO3 with a slight shape change in some modes. The relaxation processes were analyzed with the Bergmann formalism to validate the presence of two relaxation processes corresponding to grains and boundary grains contributions. These relaxations have been confirmed by studying the dielectric constant also the dielectric loss tangent is used to study the ferroelectric–paraelectric phase transition at around room temperature. The activation energy for both contributions has been calculated from the impedance, the modulus, and the dielectric loss tangent and they have almost the same values. The Nyquist plots (Z″ vs. Z′) have been adjusted using two circuits in series containing each one a resistance in parallel to a CEP capacitance.

    更新日期:2020-01-21
  • Structure, ferroelectric and magnetic characteristics of SmFeO 3 and BaTiO 3 co-modified BiFeO 3 ceramics
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-20
    Juan Liu, Miaomiao Niu, Lejiang Wang, Guorong Chen, Dong Xu

    Abstract BiFeO3 is the most important single-phase room temperature multiferroic materials. In this work, the structure, ferroelectric and magnetic properties of ternary SmFeO3 and BaTiO3 co-substituted BiFeO3 ceramics prepared by standard solid-state reaction method were investigated. The phase composition and structural transformation were characterized by X-ray diffraction and Raman spectrum analysis. The substitution of BaTiO3 leads to the phase transformation from rhombohedral R3c to pseudocubic, and the pseudocubic phase is obtained at BF008-017 ceramic. Meanwhile, the orthorhombic Pbnm phase content gradually increases with the addition of SmFeO3. According to differential scanning calorimetry (DSC) analysis results, the magnetic transition temperature TN decreases linearly with increasing B-site substitution content. The P–E hysteresis loops measured with Positive-Up-Negative-Down (PUND) method showed the enhanced ferroelectricity at BF008-01, and the maximum piezoelectric coefficient d33 obtained was 17.3 pC/N. The magnetic properties were significantly enhanced, and the best magnetic properties were achieved at BF017-008 sample, where the maximum magnetization ~ Mmax = 0.99 emu/g and remnant magnetization ~ Mr = 0.44 emu/g. The origin of the enhanced magnetism of BiFeO3-based ceramics is complex, and the substitutions of A and B sites would affect magnetic properties.

    更新日期:2020-01-21
  • Development of CuInSe 2 thin films by SELD method for photovoltaic absorber layer application
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-18
    Rajesh Niranjan, Arun Banotra, Naresh Padha

    Abstract CuInSe2 (CIS) films were obtained on annealing of 280 nm and 775 nm thick Cu/In/Se stacks deposited on corning glass substrate. The stacked elemental layer deposition (SELD) technique was used for the deposition of the films of Se, In and Cu layers. The as-deposited and annealed samples were found to possess polycrystalline structures. The films provided dominating CIS phase along with secondary phases of Cu11In9, CuSe and Se. The secondary phases present in the films vary with change in annealing temperatures. Moreover, single CuInSe2 phase is observed in the 280 nm films at 523 K. The scanning electron microscopic images of the samples show nano-rod type structures of CIS grains. The elemental composition of Cu:In:Se approaches 1:1:2 in 280 nm thick samples. The ratio, however, deviates in the 775 nm thick films. The Raman spectra of these samples give A1 mode at 173 cm−1 and confirm the presence of CIS phase. The films exhibit slow increase in the band gap (Eg) values from 1.09 to 1.22 eV for 775 films. However, comparatively higher band gap (Eg) values from 1.25 to 1.90 eV are observed for 280 nm films with high absorption co-efficient (α ~ 105 cm−1) values. The films present more useful electrical parameters for 280 nm thick samples as compared to 775 nm samples due to dominated CIS phase. Thus, obtained CIS thin films of 280 nm thickness provide viable alternative as an absorber layer in solar cell structure.

    更新日期:2020-01-21
  • Influence of CuS powder concentration on the construction of hybrid PVA/CuS thin films for polymer light-emitting applications
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-18
    Fayroz A. Sabah, Ibrahim Abdul Razak, E. A. Kabaa, M. F. Zaini, A. F. Omar

    Abstract In this study, copper sulfide (CuS) semiconductor material is combined with a polyvinyl alcohol (PVA) polymer to synthesize a hybrid organic/inorganic thin film, due to their respective intrinsic properties and extensive array of applications in optical and electrical devices. The PVA organic polymer was mixed with three different concentrations of CuS powder (0.002 g, 0.02 g, and 0.2 g), to determine the thickness of emissive layer for light-emitting applications. The structural, morphological, electrical, optical, and photoluminescence (PL) properties of the thin films were examined. The PVA/CuS thin films synthesized from CuS concentration of 0.2 g exhibited the largest grain size (37.3 nm), the highest thickness (17.48 μm), surface roughness (94.6 nm), conductivity (2.8 Ω cm, 7.55 × 103 cm2/V s, and 1.48 × 1014/cm3), the lowest bandgap (3.59 eV) and the strongest emission bands. Thus, concentration of the precursor CuS material influences the structural, morphological, electrical, optical, and photoluminescence properties of organic/inorganic thin films. In addition, FTIR and PL spectra confirmed the miscibility/bonding of PVA polymer with CuS semiconductor material and exhibited the emission bands of the films, respectively.

    更新日期:2020-01-21
  • Hierarchical Ni/Co-LDHs catalyst for catalytic oxidation of indoor formaldehyde at ambient temperature
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-18
    Tingting Jiang, Xi Wang, Jiazhi Chen, Yuliang Mai, Bing Liao, Wei Hu

    Abstract Catalytic oxidation of formaldehyde (HCHO) at ambient temperature is an effective method for indoor HCHO removal. In this study, Ni/Co-Layered double hydroxides (LDHs) with different molar ratios were successfully synthesized via a one-step hydrothermal method. Their structure and morphology were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET)-specific surface area, X-ray photoelectron spectroscopy (XPS), and H2 temperature-programmed reduction (H2-TPR), respectively. The catalytic activity results show that Ni/Co-LDHs with the Ni/Co ratio of 1:2 exhibited enhanced activity for HCHO decomposition. The removal efficiency of indoor HCHO was up to 99.7% at ambient temperature, and it remained highly stable without any obvious deactivation even after a reaction time of 800 min. The abundant hydroxyl groups were favorable for catalytic activity, which could not only enrich the adsorption of HCHO on the surface of catalysts, but also directly react with HCHO to obtain CO2 and H2O. Moreover, the redox cycles of Ni3+/Ni2+ and Co3+/Co2+ would provide more reactive oxygen species and therefore promote catalytic reaction. This work can provide a new insight into LDH-based catalysts for low-concentration HCHO removal in practical application.

    更新日期:2020-01-21
  • Optical parameters of gallium nitride doped ferrite–polypyrrole nanocomposites
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-18
    Rajani Indrakanti, V. Brahmaji Rao, C. Udaya Kiran

    Abstract Optical parameters of Gallium nitride ferrite and doped polypyrrole nanocomposites (GaNFe2O3–PPY) prepared by using Impregnation technique with different contents of (3%, 10%, 30% by weight) were studied. The gallium nitride ferrite was prepared by sol–gel technique. The UV–Vis characterisation was employed to study the absorption spectra and band gap of gallium nitride ferrite samples and their corresponding nano composites. It was observed that the absorption bands for Gallium nitride ferrite are around ~ 240 nm, ~ 260 nm and ~ 430 nm. For GaNFe2O3–PPY composites the absorption bands are shifted towards the lower wavelength side. The band gap values from Tauc’s plot were calculated and observed that with increase in dopant concentration in Gallium nitride ferrite, there is a decrease in band gap. For nano composites as the concentration of polypyrrole is increased, the band gap is decreased and the wavelength is red shifted. The parameters refractive Index, absorption coefficient, extinction coefficient, optical conductivity, theoretical electrical conductivity, dielectric constant, optical Dielectric constant, metallization criteria and reflectance are studied for all the synthesised samples.

    更新日期:2020-01-21
  • Effect of Sb doping on structural and photoelectric properties of SnO 2 thin films
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-18
    Yanfen Niu, Libing Duan, Xiaoru Zhao, Cong Han, Jiale Guo, Wangchang Geng

    Abstract Sb-doped SnO2 (ATO) thin films were synthesized via the sol–gel dip-coating method on glass substrates. The XPS and XRD spectra showed that Sb atoms were successfully incorporated into the SnO2 lattice and mostly existed in the form of Sb5+ (~ 90%) in 1 at.% ATO thin films annealed in air and further annealed in vacuum. The transmittance spectra revealed that the average transmittance was more than 75% at the wavelength range of 325–700 nm. The average sheet resistancewas 14.05 kΩ/□ in 1 at.% ATO thin films annealing in air and much less than undoped SnO2. The electric property was better when ATO thin films were further annealing vacuum compared to annealing in air. The average sheet resistance and resistivity of 1 at.% ATO thin films were 2.42 kΩ/□ and 0.035 Ω cm, respectively. The PL showed that electrons transition from a shallow level of VO to the minimum level of conduction band (CBM) increased with increasing of Sb3+ ions. The maximum level of valence band (VBM) and CBM level positions were mainly affected by Sb3+ and Sb5+ energy levels after air annealing, respectively. The behavior of surface carrier transport was investigated after further vacuum annealing. The CBM–VBM level position mainly was affected by VO energy level after further vacuum annealing. It was further proved by the Hall carrier concentration and the electrochemical impedance spectroscopy (EIS).

    更新日期:2020-01-21
  • Ferroelectric properties of the flexible Pb(Zr 0.52 Ti 0.48 )O 3 thin film on mica
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-17
    Hongyan Qi, Xin Xia, Changlin Zhou, Pengcheng Xiao, Yun Wang, Yongju Deng

    Abstract High-quality Pb(Zr0.52Ti0.48)O3 (PZT) thin film was fabricated by pulsed laser deposition on flexible mica substrates. X-ray diffraction results showed that the growth of PZT thin film is extended along (001) preferred orientation without any other secondary phases. The electrical properties measurements show that the flexible PZT thin films possess excellent ferroelectric and piezoelectric properties. The remnant polarization (2Pr) and the piezoelectric coefficient (d33) were measured to be 32 μC/cm2 and 15 pm/V, respectively, when the flexible thin film was unbending. Furthermore, the flexible PZT thin films exhibit high stability under mechanical bending. The saturated polarization and dielectric constant of PZT capacitors decrease when the capacitors change from the central area to the edge under a certain bending state. This was interpreted based on the out-of-plane tensile strain change for each capacitor.

    更新日期:2020-01-17
  • Electrical conductivity and Vickers microhardness of composites synthesized from multiwalled carbon nanotubes and carbon spheres with poly(methyl methacrylate): a comparative study
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-17
    J. M. Ambriz-Torres, C. J. Gutiérrez-García, D. L. García-Ruiz, J. J. Contreras-Navarrete, F. G. Granados-Martínez, N. Flores-Ramírez, M. L. Mondragón-Sánchez, L. García-González, L. Zamora-Peredo, O. Hernández-Cristóbal, F. Méndez, L. Domratcheva-Lvova

    Since the discovery of carbon nanotubes, they have been intensely studied as filler materials into different matrices, including polymers to obtaining composites with enhancing properties. Carbon spheres are other type of nanostructures that have not been enough studied as reinforcement material. Polymeric composites with enhanced properties have gradually replaced many of the conventional materials in several areas. In this research, a comparative study of composites based in MWCNTs and CSs incorporated in poly(methyl methacrylate) matrices by mixing solution method was carried out. Composites with 2 wt%, 3 wt%, and 4 wt% of MWCNTs and CSs were obtained through solution mixing and were characterized by scanning electron microscopy (SEM), Raman spectroscopy, and Fourier transform infrared spectroscopy (FTIR). Carbon sphere composites were observed with better dispersion than carbon nanotube composites through SEM. D, G, and G’ characteristic bands of carbon nanostructures and typical bands of PMMA were observed by Raman spectroscopy in all composites. C–H, C=O, and CH2 vibrations were depicted in composites spectra by FTIR. Vickers microhardness and electrical conductivity of composites were measured. A significant increasing in electrical conductivity was obtained in MWCNTs/PMMA composites, reaching values up to 8.45 × 10–5 S/cm. Nevertheless, the highest electrical conductivity values were observed in CSs composites (7.98 × 10–4 S/cm). Vickers microhardness also was enhanced in all composites; however, CSs/PMMA composites showed the highest values in contrast with MWCNTs/PMMA composites. The major Vickers and electrical conductivity properties of CSs/PMMA composites are attributed to better carbon spheres dispersion into polymer matrix.

    更新日期:2020-01-17
  • Effect of carbon nanotubes/graphene nanoplates hybrid to ZnO matrix: production, electrical and optical properties of nanocomposite
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-17
    Ömer Güler, Çağdaş Yavuz, Öyküm Başgöz, Serdar Altın, Ibrahim S. Yahia

    Abstract Electrical and optical properties of pure and carbon nanotube (CNT)/graphene nanoplate (GNP) mixture-reinforced zinc oxide (ZnO) matrix at different temperatures were investigated. UV–Vis absorption and electrical conductivity measurements were used in order to determine the properties were mentioned above. Samples were divided two main groups based on their matrix: one of them commercially acquired ZnO and the other one was produced via sol–gel method. Both groups have the same four sub-groups according to the percentage of the weight of the reinforcing. SEM images indicated that commercially obtained ZnO matrix has hexagonal structure while ZnO manufactured by sol–gel was mainly in sphere form. Raman spectroscopy and TEM analyses proved that graphene nanoplate structure was produced successfully, and XRD characterization shows that ZnO was produced in a suitable way by sol–gel method. The results indicated that electrical conductivity of the samples which from pure to 0.4% reinforced was decreased with increasing in reinforcing percentage. However, samples with 0.8% CNT/GNP mixture reinforcing showed greatest electrical conductivity. The highest reflection percentages of the samples were obtained from the pure specimens while the lowest ratios were observed in the highest reinforced samples. Activation energy and optical band gap values were calculated according to electrical and optical graphs.

    更新日期:2020-01-17
  • Multistep synthesis and upconversion luminescence of spherical Gd 2 O 3 :Er and Gd 2 O 3 :Er @ silica
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-17
    Nguyen Thi Quy Hai, Tran Kim Anh, Pham Thi Minh Chau, Vu Thi Thai Ha, Ho Van Tuyen, Tran Thu Huong, Ha Thi Phuong, Quoc Le Minh

    Spherical Gd2O3:Er3+ and Gd2O3:Er3+ @ silica nanoparticles have been successfully synthesized by a multistep procedure including precipitation and sol–gel processes from rare-earth nitrates, TEOS and urea as starting precursors. The structure, morphology and chemical composition of the products were characterized by X-ray diffraction, field emission scanning electron microscopy, and fourier transform infrared spectroscopy. The results indicated that the obtained phosphors consist of separated, non-agglomerated spheres in nanoscale with an uniform, ideal spherical shape. The suitable amount of TEOS was addressed to obtain the spherical Gd2O3:Er3+ @ silica nanocomposites with the luminescence intensity almost unchanged with respect to the uncoated Gd2O3:Er3+ sample. Besides, the upconversion emission spectra showed intense green and red emission bands under 980-nm laser diode excitation with remarkable increase in the red emissions. The upconversion luminescence followed the two-photon mechanism for green and red emissions. With obtained results, the prepared nanospheres are expected to be a potential material to create functional groups for subsequent bio-conjugation with various biomolecules in medical diagnostics.

    更新日期:2020-01-17
  • Radiation tolerance, charge trapping, and defect dynamics studies of ALD-grown Al/HfO 2 /Si nMOSCAPs
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-16
    N. Manikanthababu, T. Basu, S. Vajandar, S. V. S. Nageswara Rao, B. K. Panigrahi, T. Osipowicz, A. P. Pathak

    The radiation response, long-term performance, and reliability of HfO2-based gate dielectric materials play a critical role in metal oxide semiconductor (MOS) technology for space device applications. Al/HfO2/Si atomic layer-deposited devices were irradiated by gamma and swift heavy ions. An increase in the leakage current and charge trapping has been observed as the gamma irradiation dose varied from 25 to 100 krad. The density of oxide traps is found to increase with an increase in the gamma dose while the interface trap density is found to decrease. Another set of samples were irradiated by 120 MeV Au ions to study the SHI-induced defect annealing/creation of defects and intermixing effects in HfO2/Si-based devices. The formation of an interfacial layer of HfSiO at a fluence of at 5 × 1013 cm−2 is revealed by X-ray reflectivity analysis. The densities of interface- and oxide-trapped charges are found to decrease up to a critical fluence of 1 × 1012 cm−2 and then increase with further increase in fluence to 5 × 1013 cm−2. The presence of the interlayer, due to the swift heavy ion-induced intermixing, has been confirmed by X-ray photoelectron spectroscopy measurements. Various current conduction mechanisms in both substrate and gate injection cases were used to understand the basic mechanisms of direct, Fowler–Nordheim, and Poole–Frenkel tunneling, as well as Schottky emission in these devices. These studies elucidated the radiation tolerance and charge-trapping behavior of Al/HfO2/Si nMOS capacitors.

    更新日期:2020-01-17
  • Correction to: Dielectric relaxation and thermally activated a.c. conduction in (PVDF)/(rGO) nano-composites: role of rGO over different fillers
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-16
    Mervat Ismail Mohammed, Suzan Salah Fouad, Neeraj Mehta

    Unfortunately, the original version of this article has been published with error in Abstract, Table 1, Sect. 3.5 and Figs. 5 and 9.

    更新日期:2020-01-16
  • Induced ferromagnetism and enhanced optical behaviour in indium-doped barium stannate system
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-16
    M. Avinash, M. Muralidharan, S. Selvakumar, Shamima Hussain, K. Sivaji

    Abstract Structural, morphological, optical and magnetic properties of chemically synthesized Indium-doped BaSnO3 (BSO) nanostructures were investigated. XRD results indicated cubic structure from Rietveld refinements and FT-IR studies confirmed the characteristic vibrations for all doped compounds. The presence of oxygen vacancies were derived from the defect-induced Raman modes. Surface morphological studies by HR-SEM showed a significant change from pseudo-cuboids to mixed rods. The presence of oxygen vacancies, oxidation states and elements (Ba, Sn, O and In) were studied by X-ray Photoelectron spectroscopy. UV–Vis and Photoluminescence studies demonstrated a decreasing tendency in bandgap values and the presence of defect states. Interesting defect sites and F-centres were probed by Electron paramagnetic resonance studies. A transition from diamagnetic to ferromagnetic behaviour observed from room temperature magnetic measurements was explained based on F-centre exchange interaction.

    更新日期:2020-01-16
  • Dopant incited alterations in structural, morphological, optical, and dielectric properties of Er-doped LaCrO 3
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-16
    Naima Zarrin, Shahid Husain, Desh Deepak Gaur, Anand Somvanshi, Mehroosh Fatema

    The crystalline samples of La1−xErxCrO3 (x = 0.0, 0.2, 0.4, 0.6) system have been synthesized through the sol–gel process. The XRD pattern of the pristine LaCrO3 displays the single-phase characteristics having orthorhombic crystal structure with Pnma space group. On the other hand, the Er-doped samples exhibit the mixed-phase attributes of both parent and ErCrO3 compounds. The structural alteration from LaCrO3 to ErCrO3 increases with the increase in doping content. The escalation in the Er doping amount leads to a decline in the crystallite size and unit cell volume. TEM analysis verifies that the particle size reduces from 423 to 328 nm, as the content of Er in the crystal lattice is increased. The UV/Vis spectroscopy specifies that the energy band gap (Eg) values rise slightly with the increment in the doping quantity of Er in the LaCrO3. The Urbach energy is also found to increase in the doped samples. The effect of Er doping on optical constants namely refractive index, extinction coefficient, and optical conductivity has been investigated. The study on dielectric parameters infers that the dielectric constant and loss tangent (tanδ) display the typical dispersive behavior attributed to the Maxwell–Wagner interfacial polarization. These samples follow the UDR model only in the high-frequency regime. The electric modulus exploration ascertained that grains are mainly involved in the conduction process in these samples. The frequency-dependent ac conductivity plot indicated that these samples follow the Jonscher empirical power law in the given frequency range.

    更新日期:2020-01-16
  • Nano-SiO 2 @PMMA-doped composite polymer PVDF-HFP/PMMA/PEO electrolyte for lithium metal batteries
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-14
    Jian Li, Rong Hu, Hongming Zhou, Shengdong Tao, Ya Wang

    Abstract Polymer electrolytes have attracted widespread attention owing to their low cost and excellent processability. However, polymer electrolytes have yet been widely applied in commercial batteries due to their own drawbacks, such as weak mechanical properties and lower ionic conductivity. In this paper, poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) was blended with polyethylene oxide (PEO) and polymethyl methacrylate (PMMA) to build a novel polymer matrix, and SiO2@PMMA was doped into blended polymer matrix to form a composite polymer electrolyte named CPE-(SiO2@PMMA). The CPE-(SiO2@PMMA) performs superior electrochemical performance, such as a favorable electrochemical stability window (4.7 V vs Li/Li+), decent ionic conductivity (8.54 × 10–5 S cm−1 at 60 ℃), and excellent interface stability. The lithium metal battery LiNi0.8Co0.1Mn0.1O2/CPE/Li was fabricated to build a high specific energy system, which performs excellent cycling and C-rate performance compared to others polymer electrolytes. Capacity retention of LiNi0.8Co0.1Mn0.1O2/Li cell with CPE-(SiO2@PMMA) achieves 81.6% after 100 cycles, while CPE was broken with 100 cycles unfinished. All of the above favorable properties proved that PVDF-HFP/PMMA/PEO polymer matrix with SiO2@PMMA doped is a promising electrolyte candidate for flexible lithium metal batteries.

    更新日期:2020-01-15
  • Influence of the annealing temperature on the formation of Mo 17 O 47 and MoO 3 nanoparticles and their Photocatalytic performances for the degradation of MB dye
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-14
    N. Rajiv Chandar, S. Agilan, R. Thangarasu, N. Muthukumarasamy, R. Ganesh

    Abstract The present research article is about the visible light photocatalytic degradation of Methylene Blue (MB) by aqueous heterogeneous medium containing orthorhombic phase of nanocrystalline (NCs) molybdenum oxide (MoO3). The two different oxidation forms of molybdenum oxides formed at annealing temperatures of 90 °C and 400 °C are Mo17O47 and α-MoO3 nanocrystals which are found to exhibit good photocatalytic activity. In the present work, a simple conventional wet chemical method has been used to synthesize molybdenum oxide nanoparticles (NPs) by combining ammonium heptamolybdate tetrahydrate (AHMT) with capped sodium dodecyl sulfate (SDS) and ethanol solution. The orthorhombic phase is present in the samples annealed at 90 °C, 200 °C, 300 °C, and 400 °C, respectively, and it is found that the orthorhombic phase is a highly stable phase in both Mo17O47 and α-MoO3. The photocatalytic activity of the synthesized samples is estimated by using MB degradation. The photocatalytic behaviors of the synthesized Mo17O47 and α-MoO3 nanostructures have been studied using the color degradation of MB. It is found that Mo17O47 and α-MoO3 with nanorods like structure has the potential to degrade the MB dye and for a time of 90 min, the degradation efficiency of Mo17O47 and MoO3 are 56.15% and 95.78%, respectively.

    更新日期:2020-01-14
  • Study on absorbing wave of Fe 3 O 4 /MWCNTs nanoparticles based on large-scale space
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-14
    Xinhua Song, Xiaojie Li, Honghao Yan

    Research on electromagnetic stealth technology has always been one of the research hotspots. Combining the advantages of the coating absorbing model (millimeter thickness) and the structural absorbing model, the absorbing model of the nanoparticle distribution in the large-scale space (meter-scale thickness) is established. The smoke cloud clusters are applied by three different scales of 7 kg, 13 kg and 100 kg to produce space filled with Fe3O4/MWCNTs composite nanoparticles with dimensions of 3 m, 5 m and 11 m. The reflectivity R of the electromagnetic wave passing through the nano space is simulated by COMSOL software and compared with the reflectivity R′ calculated by the transmission line model. The results show that the reflectivity of the 3 m space generated by the 7 kg cloud explosion device is below − 10 dB in the 2–10 GHz frequency band, and the lowest value is − 73 dB. In the 5 m space produced by 13 kg cloud explosion device, the reflectivity value in the 2–6 GHz frequency band is below − 10 dB, and the lowest value is − 57 dB. The reflectivity of 11 m space produced by 100 kg cloud explosion device is between − 9.6 and 0 dB.

    更新日期:2020-01-14
  • Correlation between crystal structure and microwave dielectric properties of CaRE 4 Si 3 O 13 (RE = La, Nd, Sm, and Er)
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-14
    Kang Du, Zheng-Yu Zou, Xiao-Qiang Song, Jun Fan, Wen-Zhong Lu, Wen Lei

    Novel CaRE4Si3O13 (RE = La, Nd, Sm, and Er) microwave dielectric ceramics were prepared using solid-state reaction sintered at 1350–1400 °C for 5 h. CaRE4Si3O13 (RE = La, Nd, Sm, and Er) possessed an apatite structure with the P63/m space group. The lattice parameters a, b and c; theoretical density and unit cell volumes of CaRE4Si3O13 (RE = La, Nd, Sm, and Er) gradually decreased when RE changed from La to Er, and a pure phase was formed at all compositions. The εr, Q × f, and τf values of the CaRE4Si3O13 (RE = La, Nd, Sm, and Er) ceramics were related to the total ionic polarizability, packing fraction, and polyhedral distortion of RE/Ca(2)O7, respectively. The optimal microwave dielectric properties of the CaRE4Si3O13 ceramics (εr = 13.37, Q × f = 18,600 GHz, and τf = − 17.8 ppm/°C) were obtained at RE = Er.

    更新日期:2020-01-14
  • Black phosphorus nanoflakes/polyimide composite films with excellent dielectric and mechanical properties
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-14
    Renxin Xu, Jiali Ma, Rui Zhou, Huajun Sun, Dewen Xu, Zhe Zeng

    Polyimides (PIs) and their composites hold promise as low-cost alternatives to conventional ceramic-based dielectrics. Nevertheless, they are far unsatisfactory for practice applications, mainly resulting from the low interfacial compatibility between PI matrices and inorganic fillers. Herein, black phosphorous (BP) nanoflakes/PI composite films with outstanding dielectric and mechanical properties were fabricated via an in situ polymerization pathway. Owing to the hydrophilic surface of BP nanoflakes resulting from slight oxidation during fabrication, the robust noncovalent interaction between BP and PI can be formed, leading to good interfacial compatibility between the two domains and thus well dispersion of BP in PI. Even with a low BP content of 2 wt%, the composite can reach a high-permittivity value of 8.6 at 102 Hz and a low dielectric loss value of 0.02. Moreover, the BP/PI composite films inherited the good mechanical performance of PI matrix due to homogeneous dispersion and low loading of BP.

    更新日期:2020-01-14
  • Preparation of Ti-heteropolyacid/TiO 2 and its rapid photocatalytic degradation of X-3B
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-14
    Limei Ai, Danfeng Zhang, Qiang Wang, Fengwei He, Hongyuan Yang, Qingyin Wu

    Abstract The Ti-heteropolyacid H4[Ti(H2O)TiW11O39]·7H2O (TiW11Ti) loading TiO2 with different contents was prepared using dipping method. The TiW11Ti/TiO2 hybrid was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and diffuse reflectance spectra (DRS). The photocatalytic performance of TiW11Ti/TiO2 hybrid was investigated by rapid degradation of X-3B as simulated wastewater under xenon light irradiation. The different loading amount of TiW11Ti exhibited different activity. The order of different loading weights of TiW11Ti was as follows: 43 wt% TiW11Ti > 31 wt% TiW11Ti > 50 wt% TiW11Ti > 20 wt% TiW11Ti. The results revealed that the rapid degradation process followed the first-order kinetic reaction according to Langmuir equation. The TiW11Ti/TiO2 hybrid exhibited highly efficient photocatalytic activity, which was potential for environmental purification.

    更新日期:2020-01-14
  • Low consumption design of hollow NiCo-LDH nanoflakes derived from MOFs for high-capacity electrode materials
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-14
    Mingming Zhou, Fengkai Xu, Sheng Zhang, Bendong Liu, Yiming Yang, Kai Chen, Jianwei Qi

    A low consumption and facile method was employed to prepare hollow nickel–cobalt-layered double hydroxide (NiCo-LDH) nanoflakes grown in situ on nickel foam in deionized water at room temperature. By using MOFs (Metal–organic frameworks) as the precursor and then adjusting the Ni2+ ion exchange reaction time, the surface morphology and electrochemical performance of NiCo-LDH electrode materials can be greatly optimized. NiCo-LDH nanoflakes with a thickness of 150 nm as electrode material have a high specific capacity of 2148 F/g at the current density of 1 A/g and possess cycling stability of 82% capacity retention after 1000 cycles. This study provides a prominent approach for fabricating hollow nanomaterials with three-dimensional structures, and its excellent electrochemical performances make it a promising candidate for low energy consumption and high-performance energy storage devices.

    更新日期:2020-01-14
  • Effect of oxygen partial pressure on nonlinear optical and electrical properties of BNT–KNNG composite thin films
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-13
    Srinivas Pattipaka, J. Pundareekam Goud, Gyan Prakash Bharti, K. C. James Raju, Alika Khare, D. Pamu

    Composite thin films of 1–x [Bi0.5Na0.5TiO3] – x [K0.5Na0.5NbO3 + 1 wt% Gd2O3] (BNT–KNNG); (x = 0.01) have been deposited at various O2 pressures from 0.1 to 10 Pa by pulsed laser deposition, and their crystal structure, surface morphology, optical, dielectric, and ferroelectric properties were investigated. X-ray diffraction analysis of thin films deposited at 0.1 Pa revealed a single phase of BNT–KNNG and further (> 0.1 Pa), film crystallinity gradually increased with a rise in O2 pressure. The improvement in the refractive index and a reduction in optical bandgap are observed with O2 pressure and are estimated to be 2.28–2.42 and 4.08–3.65 eV, respectively. The third-order nonlinear optical coefficients estimated using the Z-scan technique are found to be enhanced with O2 pressure. The film deposited at 10 Pa exhibited a higher nonlinear refractive index (n2 = 6.188 × 10− 6 cm2/W) and a strong absorption coefficient (β = 1.043 cm/W). The temperature-dependent dielectric response displayed two structural phase transitions from rhombohedral to tetragonal phase at 165 oC and tetragonal to cubic phase at 298 oC. The enhanced dielectric (εr = 411, tanδ = 0.156 @ 1 kHz), Microwave dielectric (εr = 317 and tanδ = 0.0074 @ 10 GHz), and ferroelectric (Pr = 25.31 µC/cm2, EC = 42.62 kV/cm @ 1 kHz) properties with low leakage current are observed for the film deposited at 10 Pa which followed a space charge limited conduction behavior. The obtained microwave and nonlinear optical properties of BNT–KNNG composite films are suitable for tunable microwave and optical photonic device applications.

    更新日期:2020-01-14
  • Fabrication of WO 3 nanorod/graphene/BiV 1−x Mo x O 4 heterojunction photoelectrode for efficient photoelectrochemical water splitting
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-13
    Manman Gu, Hui Zhang, Jiuyu Ji, Xiaomin Pei

    We report the fabrication of a novel WO3 nanorod/graphene/BiV1−xMoxO4 heterojunction photoelectrode for photoelectrochemical (PEC) water splitting. The heterojunction arrays were fabricated via a hydrothermal deposition of WO3 nanorods on FTO glass, with subsequent depositing of graphene nanosheets and BiV1−xMoxO4 by spin-coating method, respectively. The structure of materials and PEC water splitting properties of the photoelectrodes were systemically investigated. The heterojunction exhibits an enhanced photocurrent density (2.27 mA/cm2 at 0.9 V vs. Ag/AgCl), which leads to a significant improvement in photoconversion efficiency (1.00% at about 0.7 V vs. Ag/AgCl). This remarkable PEC performance is mainly due to the constructive effect of the graphene (RGO) in expediting electron transfer and reducing charge recombination to realize enhanced use ratio of photo-generated carriers for the water splitting reaction. This result demonstrates the superiorities of the new graphene-mediated composites photoelectrode and provides a promising route for high-performance photoelectrochemical systems.

    更新日期:2020-01-14
  • Sr-doped yttrium nickel oxide-based photodetectors
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-13
    Mesut Yalcin, Denizhan Ozmen, Fahrettin Yakuphanoglu

    Abstract In this research, Sr-doped yttrium nickel oxide-based photodetectors have been fabricated. The electrical properties of diodes have been analyzed by using Cheung and Norde methods. The ideality factors, barrier heights, and series resistances of diodes have been calculated under visible light at different irradiation intensities. In addition, the photoresponse behavior of photodetectors was investigated under visible light at different irradiation intensities. The highest responsivity (R) and detectivity (D*) were calculated as 25.34 mA/W and 7 × 84 1011 Jones, respectively. These results suggest that the photodetectors can be used optoelectronic device applications.

    更新日期:2020-01-14
  • Alumina film deposited by spin-coating method for silicon wafer surface passivation
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-13
    Liqi Cao, Ning Yang, Shizheng Li, Xiaojun Ye, Xiao Yuan, Hongbo Li, Hua Tong

    In the present work, alumina gel was developed for passivating silicon wafers. The alumina gel was prepared by sol–gel method with aluminum sec-butoxide as precursor. After coating, rapid thermal process (RTP) was conducted to activate the passivation effect. X-ray photoelectron spectroscopy and C–V curve were executed to evaluate film properties. The peak at 74.35 eV confirmed the formation of Al2O3. Meanwhile, a small peak at low binding energy decreased with the growth of annealing temperature, which was ascribed to the escape of hydrogen, leading to the decline of effective lifetime after 700 °C. The highest fixed charge (Qf) of − 1.16e12 cm−2 and superior interface defect density at mid gap (Dit) of 1.98e12 cm−2eV−1 were obtained at the annealing temperature of 700 °C, contributing to the highest effective minority carrier lifetime of 292 µs. The present work will be helpful to provide a more cost-effective technique for Al2O3 passivation.

    更新日期:2020-01-13
  • Red emission from a novel rare earth free oxide-based CaO–0.5Al 2 O 3 –0.5Nb 2 O 5 :Mn 4+ phosphor with high water-resistance property
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-13
    Dongyu He, Yongzheng Fang, Ganghua Zhang, Yan Zhou, Yufeng Liu, Guoying Zhao, Jingshan Hou

    A 657 nm red emission from a novel rare earth free oxide-based CaO–0.5Al2O3–0.5Nb2O5:xMn4+ (0.001 ≤ x ≤ 0.008) phosphors with high water-resistance property were prepared by solid-state reaction method. The composition and structure of the as-prepared phosphors was studied. Under relative ultraviolet (331/365 nm) and blue (465 nm) light excitation, the as-prepared phosphor presents a 657 nm red emission that assigned to the 2Eg → 4A2g transition of Mn4+ ions. The red light source in CaO–0.5Al2O3–0.5Nb2O5:Mn4+ system was discussed, and the water resistance property of the phosphor was also investigated. The as-prepared phosphor presents more proper red emission position than those of similar oxide-based Mn4+-activated phosphors and shows excellent water-resistance property compared with commercial used K2SiF6:Mn4+ phosphor. With the further optimization of its photo-luminescent properties, the as-prepared CaO–0.5Al2O3–0.5Nb2O5:Mn4+ phosphors may find its potential application in the field of white LEDs.

    更新日期:2020-01-13
  • Surface modification influenced properties of silicon nanowires grown by Ag assisted chemical etching with ECR hydrogen plasma treatment
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-13
    Karanam Madhavi, Monalisa Ghosh, G. Mohan Rao, R. Padma Suvarna

    Abstract Silicon nanowires (SiNWs) are fabricated by Ag assisted chemical etching and are treated with hydrogen plasma created by electron cyclotron resonance (ECR) plasma system at 600 watts microwave power for various time durations (0–30 min). The hydrogen plasma exposure on the surface of the SiNWs reduced the surface roughness and increased the crystalline nature. SEM analysis revealed that the diameter of the SiNWs decreased on plasma exposure. The electrical conduction measurements suggested that the hydrogen plasma exposure for 5 min on the SiNW surface enhanced the electrical conductivity when compared to as fabricated SiNW surface. The hydrophobic nature of fabricated SiNWs was transformed to hydrophilic at plasma exposure for lower time duration. On plasma exposure of NWs for 30 min the sample turned hydrophobic. Study of different properties of the SiNWs before and after plasma treatment revealed that there is pronounced effect of plasma on the nature of SiNWs.

    更新日期:2020-01-13
  • Sol–gel synthesis, structural, and dielectric properties of terbium-modified $$\hbox {BaTiO}_{3}$$BaTiO3 ceramics
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-13
    Mohamed Afqir, Mohamed Elaatmani, Abdelouahad Zegzouti, Abdelhamid Oufakir, Mohamed Daoud

    Tb-doped \(\hbox {BaTiO} _{3}\) nanoparticles are prepared using the sol–gel method. The characterization was carried out using X-ray diffraction powder (XRD), Fourier transforms infrared spectroscopy (FTIR), and scanning electron microscopy spectroscopy (SEM). The FTIR analysis does not provide clear evidence on the effect of the doping amount. All diffraction peaks were perfectly matched with the pure phase of \(\hbox {BaTiO} _{3}\). The tetragonal distortion factor is smoothly dependent on the doping amount. The grains decrease in size when Tb concentration is increased. The diffusion coefficient and phase transitions do not change greatly when introducing Tb into the crystal. Fitting values of \(\gamma\) also support the evidence of normal ferro-paraelectric transition. Doped materials have a dielectric constant greater than undoped material, a meanwhile low loss is observed. The presence of Tb inhibits the formation of oxygen vacancies and promotes the stabilization of the oxygen-deficient system with the support of tetragonal phase formation during the sintering process.

    更新日期:2020-01-13
  • Strontium titanate with inverse opal structure as the photocatalysts
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-13
    Juan Xie, Kai Lei, Hu Wang, Chenjie Wang, Biao Liu, Lei Zhang, Penghui Bai

    Abstract The microstructure of the catalyst material is one of the most important factors affecting the photocatalytic performance. In this study, inverse opal structure strontium titanate (SrTiO3, STO) materials with different pore sizes (from 75 to 123 nm) were prepared, and employed as photocatalysts in the degradation of rhodamine B (RhB) dye. The results suggest that the highest photodegradation rate of the inverse opal structure photocatalyst reaches to 88.03%, which is greater than that of the non-inverse opal structure (50.42%) due to its complex three-dimensional porous microstructure. The effect of the pore size of the inverse opal structure STO on the photocatalytic properties was investigated. As the pore size of the inverse opal microstructure decreases, the photocatalytic degradation rate increases regularly, attributing to effective capture of light with decreasing of pore size. The photocatalytic degradation mechanism of inverse opal structure with different pore sizes is discussed in this work.

    更新日期:2020-01-13
  • Preparation and characterization and photoluminescence properties of CeF 3 @ZnS nanocomposites
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-13
    H. Ahmadi, M. Bagherzadeh, M. Raeisi, F. Payami

    In the present work, new nanocomposites of CeF3@ZnS with various weight ratios (1:1, 1:3, 1:5 and 1:7) were synthesized by wet chemistry method and characterized by using XRD, SEM, EDX, and TEM techniques. The optical spectra of the prepared nanocomposites were measured at room temperature and analyzed here for the first time. The obtained results showed an enhancement in energy transfer rate from CeF3 to ZnS nanoparticles due to large overlapping of CeF3 emission and ZnS absorption spectra. The presence of ZnS nanoparticles around CeF3 nanoparticle as core–shell structure lead to shift a defect state originated from emission peak at 480 nm in pure ZnS nanoparticles. Effect of ZnS nanoparticle amount, in photoluminescence properties of CeF3@ZnS nanocomposite, was investigated and obtained results are presented and discussed.

    更新日期:2020-01-13
  • Novel blue-emitting KBaGdSi 2 O 7 :Eu 2+ phosphor used for near-UV white-light LED
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-11
    Qinjiang He, Renli Fu, Weijun Gao, Haitao Zhu, Xiufeng Song, Xinqing Su

    Novel blue-emitting KBaGdSi2O7:Eu2+ phosphors were designed and synthesized through solid-state reaction method. The structural properties, concentration, and temperature-dependent luminescence behaviors of these phosphors were investigated in detail in this paper. Studies revealed that KBaGdSi2O7:Eu2+ phosphors have an intense absorption in the broad wavelength ranging from 250 to 400 nm that is suitable for the commercial near-UV LED, and give out intense blue light peaked at 475 nm with a full-width half-maximum of 75 nm. The crystallographic information of KBaGdSi2O7 phase is revealed from XRD pattern by Rietveld refinement. Band gap is derived to be 3.93 eV through diffuse reflection spectra through Kubelka Munk function. The concentration quenching mechanism is identified as the dipole–dipole interaction. Moreover, the thermal quenching experiment was also conducted and the activation energy is calculated as 0.3069 eV, which indicates this novel KBaGdSi2O7:Eu2+ phosphor has good thermal stability. These properties exhibit its potential commercial application for near-UV white-light LEDs (w-LEDs).

    更新日期:2020-01-13
  • Glycine-A bio-capping agent for the bioinspired synthesis of nano-zinc oxide photocatalyst
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-11
    Parita Basnet, Dhrubajyoti Samanta, T. Inakhunbi Chanu, Satadru Jha, Somenath Chatterjee

    Structural modification of nanoparticles (NPs) for application-specific study is timely. In the present investigation, an attempt has been made for the bioinspired synthesis of zinc oxide (ZnO) NPs possessing different morphologies using glycine as the bio-capping agent. A variation in the amount of glycine during low-temperature mediated solid-phase synthesis indicated that a higher ratio of glycine directed the ensemble of nanohexagons into nanobundles which further formed nano-flower buds- like morphology, while least concentration formed agglomerated NPs and moderate concentration of glycine was able to modify the NPs’ structure into nanorods. On the other hand, the utilization of solution-phase synthesis methods, i.e. co-precipitation and hydrothermal, led to the formation of thinner and thicker ZnO nanosheets, respectively. In terms of crystalline structure, not much difference was observed in the lattice parameters or the unit cell of the crystal, with approximately similar crystallite sizes. From Fourier transform infrared spectroscopy, the functionalization of glycine from both the amine and the carboxyl group was noted. Further, it was found that the morphology and photoluminescence emission spectra of the samples were inter-related, wherein higher the agglomeration of the particles, greater the intensity of the visible region defect band was observed. The as-synthesized ZnO-photocatalysts were then employed for the degradation of rhodamine B (RhB), a major effluent of the textile industry. The photocatalytic activity of the samples was found to depend upon the surface area, which in turn was related to the morphology and the magnitude of green emission defect states. About 99% RhB degradation was obtained with ZnO possessing nano-flower buds-like morphology within 60 min of sunlight irradiation. Additionally, the role of reactive oxidative species and the stability of this photocatalyst were investigated.

    更新日期:2020-01-13
  • Solution for green organic thin film transistors: Fe 3 O 4 nano-core with PABA external shell as p-type film
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-11
    Cristian Ravariu, Dan Eduard Mihaiescu, Alina Morosan, Daniela Istrati, Bogdan Purcareanu, Rodica Cristescu, Roxana Trusca, Bogdan Stefan Vasile

    Abstract We report the first successful green synthesis route for organic transistors based on para-aminobenzoic acid (PABA) grafted to ferrite nanoparticles, at room temperature. The obtained core–shell nanoparticles (NCS) have been investigated by DLS, FT-IR, SEM, TEM. Both average hydrodynamic diameter and zeta potential of synthesized PABA-NCS nanoparticles has been identified, indicating a good stability of this nano-compound. SEM analysis proved a heterogeneous structured material with quasi-uniform granular formations in size, while TEM revealed a ferrite core of 20 nm. The measurements of output characteristics in the saturation regime and transfer characteristics at negative gate voltages have proved that an organic transistor based on PABA-NCS has been accomplished. The current increasing over a negative threshold voltage demonstrated an accumulation channel onset in the PABA-NCS thin film. This is a final argument for the p-type behavior of the PABA-NCS film.

    更新日期:2020-01-13
  • Mesoporous Gd 2 O 3 /NiS 2 microspheres: a novel electrode for energy storage applications
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-10
    S. Dhanalakshmi, A. Mathi Vathani, V. Muthuraj, N. Prithivikumaran, S. Karuthapandian

    Development of novel Faradic electrode with excellent rate capability and long-lasting characteristics determines the performance of supercapacitor (SC) in current scenario. Rare-earth metal oxides have received considerable attention in SC domain with high volumetric energy density and capacitive performance. In this context, we have fabricated gadolinia/nickel sulphide nanocomposite via simple chemistry approach followed by two step hydrothermal method. Especially, the gadolinia/nickel sulphide nanocomposite synthesized in the current study offers high specific capacitance (354 F g−1 at a constant current density of 0.5 A g−1), low charge transfer resistance (6.37 Ω) and outstanding cycle life (1.3% loss capacitance loss even after 5000 continuous charge/discharge cycles). Such enduring energy characteristics of gadolinia based nanocomposite will create a huge impact in the future energy storage systems

    更新日期:2020-01-11
  • 3D segregated architecture BaTiO 3 /polystyrene composites with enhanced dielectric constant fabricated via hot pressing core–shell polystyrene@BaTiO 3 composite microspheres
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-10
    Jian Ye, Biao Zhang, Yicheng Jin, Haoqian Zhang, Yingjie Qiao, Zhiguo Zhang

    How to obtain high dielectric constant using low filler content is one of the urgent problems to be solved in the research field of ceramic/polymer dielectric materials. In traditional methods (fillers are randomly distributed), filler particles are isolated by thick layers of polymers (with low dielectric constant), which usually result in ultra-low enhancement efficiencies of dielectric constant for the composites. To solve the above puzzle, this study provides a new strategy to improve the dielectric constant of ceramic/polymer composites, that is constructing 3D segregated architectures of BaTiO3 (BT networks) in polystyrene (PS) matrix. This strategy is expected to enhance dielectric interaction between BT particles and greatly improve the dielectric constant of BT/PS composites. In this method, PS@BT core–shell microspheres were firstly fabricated by electrostatic self-assembling the BT particles on PS microspheres. BT/PS composites with BT networks were constructed by hot pressing above core–shell microspheres. Microstructures of PS@BT microspheres and BT/PS composites were investigated. Dielectric properties of BT/PS composites with various BT contents were studied. Results show that dielectric constant of the BT/PS composites is up to 41.8 when BT content is only 30vol%, which is much higher than that of traditional composites. This research provides us a facile method to design and fabricate ceramic/polymer composites with high dielectric constant and low loss.

    更新日期:2020-01-11
  • Facile synthesis of Sb-Sb 2 O 5 @P@C composite and study for the supercapacitor application
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-10
    Zongsheng Cao, Zhengchun Yang, Cong Zhang, Liqiang Xie, Xinhao Zhao, Peng Pan, Yujie Yuan, Wen Qi, Jie He, Honghao Zhang, Tao Xue, Ping Zhang, Jun Wei, Kailiang Zhang, Jinshi Zhao

    Abstract A Sb-Sb2O5@P@C composite was synthesized using a two-step high-energy mechanical milling (HEMM) method using metal antimony, red phosphorus, and carbon as raw materials. XPS, XRD, and Raman spectroscopy clearly showed that the Sb was partially oxidized to become Sb2O5 during the milling process and that some of the red phosphorus was converted to black phosphorus. A specific capacitance of 109.7 F g−1 was achieved at a current density of 0.5 mA cm-2 in the obtained Sb-Sb2O5@P@C composite, and the packaged supercapacitor prepared with the Sb-Sb2O5@P@C composite was found to maintain a capacitance retention of 77.3% after 5000 cycles at a current density of 2 A g−1. This study therefore provides a possible direction for the selection of electrode materials the perform well for application in supercapacitors.

    更新日期:2020-01-11
  • Structural, magnetic, and electrical characterization of Sr-substituted LaFeO 3 perovskite synthesized via sucrose auto-combustion route
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-10
    M. A. Gabal, F. Al-Solami, Y. M. Al Angari, A. Awad, A. A. Al-Juaid, A. Saeed

    In this work, a series of Sr-substituted lanthanum orthoferrite perovskites, La1−xSrxFeO3 (x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0), were prepared using the sucrose-assisted auto-combustion route to study the effect of Sr-substitution on the structural, magnetic, and electrical properties and to investigate the impact of the entire method on different properties. The auto-combustion process and the perovskites formation were followed using differential thermal analysis–thermogravimetry techniques. The obtained different phases were characterized using X-ray diffractometer (XRD), Fourier transform infrared spectroscopy, and high-resolution transmission electron microscopy HRTEM measurements. XRD revealed peaks attributed to SrCO3 secondary phase increases in their intensity by increasing Sr-content till predominate at x = 1.0. It also showed a transfer from orthorhombic symmetry to rhombohedral one by increasing Sr-content. The obvious contraction in the unit cell parameters by Sr-substitution could be attributed to the Fe3+ → Fe4+ oxidation occurred to balance the total charge on molecule. The obvious increase in the magnetization by increasing Sr could be attributed to the formation of Fe4+ ions, strengthening the ferromagnetic component through sharing in the double-exchange interaction, Fe4+–O–Fe3+, as well as the formation of oxygen vacancies that disturb the uncompensated surface spin. Ac-conductivity measurements indicated a change in the entire conduction mechanism from electronic to ionic with improving conductivity by increasing Sr-content. Generally, the utilized sucrose method indicated an improvement in the obtained magnetization accompanied by lowering conductivity than previously reported systems in literature.

    更新日期:2020-01-11
  • Improved ethanol gas-sensing properties of optimum Fe–ZnO mesoporous nanoparticles
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-10
    Yue Shen, Qinyi Li, Tai Li, Meng Cao, Feng Gu, Linjun Wang, Da-Ming Zhu

    Abstract Fe-doped ZnO (Fe–ZnO) mesoporous nanoparticles have been synthesized via a facile hydrothermal method, which utilizes pluronic triblock copolymer polyethylene glycol–polypropylene glycol–polyethylene glycol (PEO-PPO-PEO) as the pore-forming agent. Fe–ZnO composites have an unique porous structure. Their pore sizes increase with Fe-doping concentration and reach a maximum as Fe concentration is 15 at.%; the specific surface area of synthesized mesoporous Fe–ZnO nanoparticles reaches a maximum as the Fe concentration is about 11 at.%. Electron microscopy, vapor pressure isotherm measurements and photoluminescence (PL) were used to characterize synthesized Fe–ZnO composites. Fe–ZnO-based gas sensors exhibit excellent response in detecting ethanol; the sensing response of Fe(11 at.%)–ZnO reaches 319.8, which is significantly higher than most of the ZnO-based gaseous sensors. The improved sensitivity is ascribed to the increase of oxygen-related defects and specific surface area of Fe–ZnO composites.

    更新日期:2020-01-11
  • Electrodeposition and texture control of Ag-doped SnS thin films with high-electrical transmission properties
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-10
    Sibo Hu, Ying Liu, Jingjun Liu, Zhengping Zhang, Jing Ji, Zhilin Li, Feng Wang

    SnS is widely noticed in optoelectronics and thermoelectric fields. But the low-electrical transmission performance confines its actual application. In this paper, Ag-doped SnS thin films were successfully prepared by a sample electrodeposition method. The mechanism of the S and Sn co-deposition and the effect of complexing agent K4P2O7 were studied. The Ag content was successfully controlled by the adjustment of the electrolyte and deposition parameters. The b-axis texture was strengthened by Cetyl trimethyl ammonium bromide (CTAB) in the electrolyte. The carrier concentration was promoted by the control of Ag content and the carrier mobility was promoted by the strengthening of the b-axis texture. The electrical conductivity was promoted by the combination of the Ag concentration control and b-axis texture control. It reached the highest known value of 1.40 S cm−1 under the highest b-axis texture coefficient. Such a sample combination method and control strategies provide a new view for the preparation of semiconductors with high-electrical transmission properties.

    更新日期:2020-01-11
  • High sensitive polyaniline nanosheets (PANINS) @rGO as non-enzymatic glucose sensor
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-09
    Saraswathi Kailasa, R. Kiran Kumar Reddy, M. Sai Bhargava Reddy, B. Geeta Rani, Hussen Maseed, R. Sathyavathi, K. Venkateswara Rao

    Abstract This study aims the amperometric enzyme-free glucose sensing of interlayered Polyaniline nanosheets @reduced grapheme oxide (PANINS@rGO). Conductive PANINS were synthesized using in situ chemical oxidative polymerization method. The PANINS@rGO nanocomposite was prepared by the solution mixing method and as-synthesized material was fully examined using various spectroscopy and microscopy techniques. PANINS@rGO composite coated on screen-printed carbon electrode (SPCE) was studied for electrochemical behaviour for the detection of non-enzymatic glucose. The fabricated sensor matrix was tested towards detection of glucose efficacy using cyclic voltammetry (CV) and Chronoamperometry (CA) techniques in the presence of 0.1 M NaOH electrolyte in a range of 1–10 mM at an optimum working potential of 60 mV s−1. PANINS@rGO/SPCE absorbed with high sensitivity (3448.27 μA mM−1 cm−2) and excellent low detection limit (LOD) 30 nM, (S/N = 3). Furthermore, the obtained results of the proposed PANINS@rGO/SPCE fabricated a finite sensor for non-enzymatic glucose sensor. Thus this report proves the practical opportunities for the development of environmentally benign, cost effective and chemically stable electrode materials for sensors, which may be beneficial for the expansion of economically viable enzyme free electrochemical glucose sensor devices.

    更新日期:2020-01-09
  • Microwave absorption and infrared stealth performance of reduced graphene oxide-wrapped Al flake
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-09
    Qi Fan, Ligang Zhang, Honglong Xing, Huan Wang, Xiaoli Ji

    A novel Al@reduced graphene oxide (Al@RGO) composite was designed and synthesized by a one-step hydrothermal method. We investigated the effect of the graphene on the microwave absorbing properties and infrared emissivity of composites. The crystal structure, microscopic morphology, infrared emissivity and electromagnetic parameters of the prepared samples were characterized by XRD, FESEM, TEM, XPS, dual band infrared emissometer and vector network analyzer. TEM and SEM show that the thin Al sheet is uniformly wrapped by RGO with a crumpled surface. Functionalized RGO and surface cation-modified Al sheets are tightly compounded through an electrostatic interaction. The oxygen content and defect from RGO as polarization center endows the material with enhanced molecular polarization and dipole polarization effect. The Al sheet is well coated with RGO, enhancing interface polarization and impedance matching. The minimum reflection loss (RL) of optimized Al@RGO composites is − 46.11 dB at 13.68 GHz under the coating thickness of only 2 mm. The bandwidth below − 10 dB can reach 4.88 GHz (11.52–16.4 GHz). Al sheet is a suitable base material for both microwave absorption and infrared stealth. The Al@RGO composites exhibit excellent infrared stealth ability, and their lowest infrared emissivity is 0.62. Thus, Al@RGO composites show potential application for both electromagnetic wave absorption and infrared stealth.

    更新日期:2020-01-09
  • Structural characterization and electrical properties of Nd 2 O 3 by sol–gel method
    J. Mater. Sci. Mater. Electron. (IF 2.195) Pub Date : 2020-01-09
    Ramazan Lok, Erhan Budak, Ercan Yilmaz

    In the current study, Neodymium oxide (Nd2O3) was prepared by sol–gel method and deposited on P-type 〈100〉 silicon wafer. The chemical characterization of samples was done by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectra (EDS) and atomic force microscopy (AFM). Nd–O bond formation was proven by FTIR, also cubic- Nd2O3 (c-Nd2O3) phase was detected by XRD. According to EDS analysis, neodymium concentration was approximately 59.41% while oxygen concentration was calculated as 10.21%. The amount of excess oxygen was 9.45% was originated by cristobalite formation. In addition, electrical characterizations of Nd2O3/p-Si MOS capacitor was performed by capacitance–voltage (C–V), conductance–voltage G/ω–V measurements at different frequencies between 250 kHz and 1 MHz. The maximum value of measured capacitance–voltage (C–V) and conductance–voltage (G/ω–V) was increased with decreasing in the applied voltage frequencies and after series resistance (Rs) correction, the measured C–V and G/ω–V characteristics, G/ω behavior started to decrease with rising the frequencies. According to the observed frequency dispersion, the deposited Nd2O3 on P-type 〈100〉 silicon exhibits stable insulation property for future microelectronic applications.

    更新日期:2020-01-09
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