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Z-scheme Bi2WO6/CuBi2O4 heterojunction mediated by interfacial electric field for efficient visible-light photocatalytic degradation of tetracycline
摘要： In order for the removal of Tetracycline (TC) in wastewaters, an efficient binary Bi2WO6/CuBi2O4 Z-scheme heterojunction photocatalyst was synthesized by loading Bi2WO6 (BWO) nanoparticles on CuBi2O4 (CBO) nanorods via a solvothermal route. The obtained Bi2WO6/CuBi2O4 composite displays photocatalytic activity for TC degradation more than five times higher than that for pure CBO nanorods. The recycling experiment shows that over 91% of TC can be photo-degraded by the optimal Bi2WO6/CuBi2O4 photocatalyst within 60 min even after four cycles. Results of SEM, transient photocurrent response, EIS measurement prove that solvothermal process for BWO loading can introduce rough surface with high-density negative charge on CBO, contributing to effective photo-induced carrier transfer. XPS, Mott?Schottky plots and PL spectra reveal that the loading of BWO as well as interfacial charge redistribution can induce the formation of interfacial electric field for Z-scheme heterojunction, contributing to the high oxidation and reduction capabilities ability of Bi2WO6/CuBi2O4 composite. The study on photocatalytic mechanism discloses that hole (h+) and superoxide radical (?O2?) are dominating reactive oxidation species (ROS) in the photodegradation process. This study has provided a novel route to fabricate Z-scheme photocatalysts for effective photocatalytic degradation processes.
关键词： charge transfer,Z-scheme heterojunction,environmental materials,interfacial electric field,photocatalysis,tetracycline degradation
更新于2025-11-21 10:59:37
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Multi-doped bismuth ferrite thin films with enhanced multiferroic properties
摘要： Thin films of multi-doped bismuth ferrite, Bi0.97?xLaxSr0.03Fe0.94Mn0.04Co0.02O3 (BLxSFMC, x = 0.00–0.18), are synthesized on a fluorine-doped tin oxide (FTO)/glass substrate. The structure and multiferroic properties of the film samples are characterized and tested. The results indicate that on doping, the structure of the BLxSFMC film changes has been changed. The concentrations of both oxygen vacancies and Fe2+ are decreased. The BL0.18SFMC thin film exhibits Ohmic conduction, which reduces the influence of the built-in electric field Ebi of the space-charge region at the interface between an Au electrode and the BLxSFMC during polarization. The BL0.18SFMC thin film also exhibits enhanced ferroelectric properties than the undoped film, with a higher residual polarization of 188 μC/cm2 and a higher squareness ratio of 1.21. Meanwhile, the reduced number of oxygen vacancies also reduces the Fe2+/Fe3+ ratio, thereby enhancing the Dzyaloshinskii–Moriya interaction of Fe–O–Fe bonds, and so the BL0.18SFMC thin film exhibits enhanced ferromagnetism, with a saturation magnetization of Ms ≈ 3.94 emu/cm3. Thus, multi-ion doping can improve both the ferroelectric and ferromagnetic properties of BLxSFMC thin films.
关键词： Ohmic conduction,built-in electric field,oxygen vacancy,multiferroic
更新于2025-11-14 17:28:48
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Enhanced photoelectrochemical performance of Zn2SnO4N by interstitial N induced the build-in polarization electric field
摘要： Highly active Zn2SnO4N photocatalysts were successfully prepared by the one-step microwave-assisted solvothermal method. N heteroatoms were introduced into Zn2SnO4 by occupying the interstitial sites, inducing the formation of the build-in polarization electric field and the impurity level which was advantageous to promote the separation and the migration of photoinduced electron-hole pairs. As a result, the as-prepared Zn2SnO4N exhibited improved the photoelectrochemical properties and the photodegradation rate of RhB over Zn2SnO4N had been demonstrated to increase 3.3 times compared to that of pure Zn2SnO4. Under the effect of the built-in electric field, the impurity level served as a springboard for electron transition rather than a recombination center, which caused the enhancing photocatalytic performance. The finding may provide a new insight into understanding the mechanism of doping modification.
关键词： N-doped,Zn2SnO4,Build-in electric field,Photocatalysis,Impurity level
更新于2025-11-14 17:04:02
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Upconversion photoluminescence modulation by electric field poling in Er3+ doped (Ba0.85Ca0.15) (Zr0.1Ti0.9)O3 piezoelectric ceramics
摘要： Luminescent piezoelectric materials promise a stratagem for controlling the optical process by electric field, which would benefit for future optoelectronic devices. Here, Er3+ doped (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 (BCZT: Er3+) piezoelectric ceramics are prepared to demonstrate the proof of concept. In addition to excellent intrinsic piezoelectricity and ferroelectricity, BCZT: Er3+ ceramics exhibit simultaneously strong green upconversion emissions under excitation of 980 nm. Remarkable photoluminescence (PL) quenching phenomenon as well as significant changes on relative intensities of stark lines are observed under external poling electric field. Furthermore, field dependent piezoelectric constant d33 and photoluminescence quenching ratio show similar variation trend and finally saturate for E>3.5 kV/mm, which provides a noncontact strategy to monitor the piezoelectric constant d33. The PL quenching triggered by electric field in BCZT: Er3+ ceramics is ascribed to the decreased asymmetry originating from field-induced structural transformation from a significant fraction of the tetragonal phase to rhombohedral phase. Our work would be helpful for expanding the scope of luminescent piezoelectric materials and promising future optoelectronic and optical devices with cross-coupled physical properties.
关键词： Piezoelectric,Electric field poling,Photoluminescence,Ferroelectric polarization
更新于2025-11-14 15:28:36
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Modulated charge transport characteristics in solution-processed UV photodetector by incorporating localized built-in electric field
摘要： The application of ZnO in the field of ultraviolet (UV) photodetectors is hindered by the lower responsivity, which is attributed to the strong band-to-band direct recombination caused by its large exciton binding energy and defect-assisted charge recombination related with the presence of defect states. Here, a solution-processed ZnO:Poly[N-90-heptadecanyl-2,7- carbazole-alt-5,5-(40,70-di-2-thienyl-20,10,30-benzothiadiazole)] (PCDTBT) composite photosensitive layer is employed to overcome these shortcomings. By incorporating PCDTBT, the localized built-in electric field can be constructed, which effectively facilitates the photogenerated exciton dissociation in annealing-free ZnO layer. Meanwhile, the formed depletion region in dark reduces the majority carrier density, thus decreasing the dark current of the photodetector. Furthermore, the absorption spectrum of PCDTBT perfectly overlaps the photoluminescence of ZnO, which is beneficial for the reutilization of carrier recombination energy by fluorescence resonance energy transfer. This study reveals that the charge recombination loss in ZnO limits the photoresponse, and points a direction to improve the light detection capacity of UV photodetectors.
关键词： ZnO,UV photodetector,Solution-processed,PCDTBT,Built-in electric field
更新于2025-11-14 15:27:09
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High Breakdown Strength Schottky Diodes Made from Electrodeposited ZnO for Power Electronics Applications
摘要： The synthesis of ZnO films by optimized electrodeposition led to the achievement of a critical electric field of 800 kV/cm. This value, which is 2 to 3 times higher than in monocrystalline silicon, was derived from a vertical Schottky diode application of columnar-structured ZnO films electrodeposited on platinum. The device exhibited a free carrier concentration of 2.5 × 10^15 cm^-3, a rectification ratio of 3 × 10^8 and an ideality factor of 1.10, a value uncommonly obtained in solution-processed ZnO. High breakdown strength and high thickness capability make this environment-friendly process a serious option for power electronics and energy-harvesting.
关键词： breakdown voltage,electrodeposition,zinc oxide,critical electric field,solution-processed,Schottky diode,power diode,ideality factor
更新于2025-09-23 15:23:52
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Chemical Sensing Performance of Flower-Like ZnO/PSi Nanostructures via Electrochemical Impedance Spectroscopy Technique
摘要： ZnO nanostructures were synthesized on porous Si (PSi) structures using a method developed by this study known as electric field-assisted aqueous solution technique. The detailed characterization of this nanostructure was performed using atomic force microscopy, field emission scanning electron microscopy, x-ray diffraction, room-temperature photoluminescence and Raman spectroscopy. Electrochemical impedance spectroscopy (EIS) technique was used to detect two classifications of chemical solvents, namely polar and non-polar solvents. Nyquist plots in EIS were utilized to detect chemical solvents (ethanol, acetone, toluene and benzene) exposed to ZnO/PSi nanostructure arrays. The results showed that the grown flower-like ZnO nanostructure arrays served as good chemical sensors with high sensitivity and low power consumption. Meanwhile, the ZnO/PSi nanoflowers exposed to ethanol showed the highest sensitivity (94.6% response) compared to other chemical solutions with the least response exhibited by benzene (68.4% response). It was postulated that the interaction between the solution and oxygen species of ZnO/PSi nanostructure surface induced a resistance change resulting in the release of free electrons that migrated to the conduction band of ZnO/PSi nanoflower structures and reduced the number of surface-adsorbed oxygen species. Subsequently, the changes observed in the Nyquist semicircle diameter and Warburg impedance led to the chemical sensing response.
关键词： ZnO/PSi nanoflower,electric field-assisted aqueous solution technique,Chemical sensors,electrochemical impedance spectroscopy,Nyquist plot
更新于2025-09-23 15:23:52
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Large electric field-induced strain in ternary Bi0.5Na0.5TiO3-BaTiO3-Sr2MnSbO6 lead-free ceramics
摘要： The large electric-field-induced strain of Bi0.5Na0.5TiO3-BaTiO3 based ceramic make it a potential replacement for lead-based ferroelectrics in actuator applications. Herein, a ternary system (1-x)(Bi0.5Na0.5)0.935Ba0.065TiO3-xSr2MnSbO6 (BNBT6.5-xSMS) ceramic was fabricated using conventional solid-state reaction. It was found that the ferroelectric to relaxor phase transition temperature TF-R gradually shifted to lower temperature by increasing SMS contents. The ferroelectricity and piezoelectricity of BNBT6.5 were highly affected by trace amount of SMS doping. For composition BNBT6.5-0.003SMS, where TF-R was near room temperature, a large electric-field-induced unipolar strain of ~0.4% with high normalized strain (Smax/Emax) of 728 pm/V, which is comparable to lead-based ferroelectric/antiferroelectric ceramics, was achieved owing to the reversible electric-field-induced phase transition between a non-polar relaxor phase to a polar phase with long-range ferroelectric order.
关键词： electric-field-induced phase transition,ferroelectric,Lead-free ceramics,Bi0.5Na0.5TiO3
更新于2025-09-23 15:23:52
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Stark shift in Y <sub/>2</sub> SiO <sub/>5</sub> :Er <sup>3+</sup> by the photon echo beating method
摘要： The coefficient of a linear Stark shift of the 4F9/2–4I15/2 transition of Er3+ ion in Y2SiO5 is measured (14.3 kHz V?1 cm ) by splitting the upper and lower levels of the transition by a pulsed electric field and measuring the splitting frequency from the period of beatings of the temporal form of a photon echo signal (stark photon echo beating method). The linear Stark coefficients of Er3+ transitions in Y2SiO5 have not been measured before, and this is a valuable result for a number of applications such as gradient echo memory, group velocity control via spectral hole burning, etc.
关键词： Er3+,phase control,Stark coefficient,Stark photon echo beating,Y2SiO5,YSO,low electric field pulse
更新于2025-09-23 15:23:52
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[IEEE 2018 17th International Conference on Ground Penetrating Radar (GPR) - Rapperswil, Switzerland (2018.6.18-2018.6.21)] 2018 17th International Conference on Ground Penetrating Radar (GPR) - Calculation of the Transient Electric Field Transmitted in a Lossy Medium Radiated by an Equivalent GPR Dipole Antenna
摘要： The paper deals with the characterization of electric field radiated by a GPR antenna and transmitted into a lossy medium. Realistic bow-tie GPR antenna is modeled as an equivalent dipole antenna with current distribution governed by Hallen integral equation. Electric field transmitted into a lossy medium is determined using Boundary Element formalism for the solution of field integral formulas. Electric field distribution at a certain depth is calculated using this procedure.
关键词： transmitted electric field,time domain analysis,lossy medium,equivalent dipole antenna
更新于2025-09-23 15:23:52