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White light-emitting diodes (WLEDs), which have high luminous brightness, longevity, low energy consumption and friendliness of environment, could be employed in diverse fields. Nevertheless, commercial phosphors are short of red light component. New phosphors which can emit red light are required. Mn 2+ doped aluminum nitride (marked as AlN) red phosphors were prepared by a simple solid-state reaction. X-ray diffraction (XRD), scanning electron microscope (SEM), high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS), as well as photoluminescence (PL) spectra are utilized to characterize the prepared samples. The preparing process of AlN phosphors, phase formation and crystal structure, morphology, and photoluminescence are detailedly investigated. For Mn 2+ doped AlN phosphor(marked as AlN:Mn 2+ ), it exhibits an intense red emission caused by the 4 T 1 ( 4 G)- 6 A 1 ( 6 S) transition of Mn 2+ . The unusual red emission of Mn 2+ is ascribed to the strong nephelauxetic and crystal field between Mn 2+ and the tetrahedrally coordinated N 3− . The oxygen-related defects in AlN have a great influence on the photoluminescence properties of the Mn 2+ doped AlN. The AlN:Mn 2+ phosphors exhibits a high brightness, high color purity, and lower saturation, which make it a great candidate of red phosphors for white light-emitting diodes (WLEDs). [ABSTRACT FROM AUTHOR]

Ce 3+ and Tb 3+ ion co-doped aluminum nitride (AlN) phosphors were prepared by a simple solid-state reaction. X-ray diffraction (XRD), high resolution transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS), as well as photoluminescence (PL) spectra were employed to analyze the samples. The crystal structure, morphology, photoluminescence properties and the energy transfer process of Ce 3+ and Tb 3+ ion co-doped AlN phosphors were carefully investigated. An enhanced light emission and red-shifted excitation wavelength can be observed in AlN:Tb phosphors after co-doped with Ce 3+ ion. The results indicate that the Ce 3+ and Tb 3+ ion co-doped AlN phosphors can be effectively used in fingerprint identification. The phosphor-marked fingerprints on various substrates can be clearly manifested with good contrast and weak background inference, holding significant applications in the forensic field. [ABSTRACT FROM AUTHOR]

• The FeNi/C composites were prepared by room temperature precipitation and high temperature calcination. • The synthesized material has a unique three-dimensional network structure that can optimize impedance matching. • The material has the synergistic effect of multi-loss mechanism. • The optimal minimal reflection loss reaches − 52.99 dB at 3 mm. In this paper, the carbon coated iron nickel nanoparticles were obtained by calcining PVP crosslinked iron nickel oxalate. The morphology, structural composition and microwave-absorbing (MA) properties of the composites were analyzed by various characterization methods. The results show that FeNi/C composites have excellent impedance matching characteristics and MA performance in multiple frequency by virtue of their microscopic network structure. At the same time, through the analysis of loss mechanism, we found that the material has high dielectric loss and magnetic loss characteristics. Under the joint action of various loss mechanisms such as interface polarization and eddy current loss, the material has a high reflection loss (RL) value at different frequency. At a thickness of 3 mm, the sample FNC12 has a minimum RL of − 52.99 dB at 3.6 GHz. The effective absorption bandwidth (EAB) (RL ≤ −10 dB) is 1.81 GHz. [ABSTRACT FROM AUTHOR]

The (Fe 1- x Nd x ) 3 C nanoparticles (NPs) were prepared by a sol-gel method. The structure, morphology and magnetic properties were investigated by X-ray diffraction, Raman spectra, transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). Analysis results show that the (Fe 1- x Nd x ) 3 C NPs were embedded in multi-walled carbon nanotubes and displayed ferromagnetic properties. And it is indicated that their saturation magnetization (M s ) values tend to decrease with increasing the Nd doping concentration. More importantly, we propose a possible mechanism to explain the formation process of the (Fe 1- x Nd x ) 3 C NPs. [ABSTRACT FROM AUTHOR]

With the development of electronic information technology, the miniaturization of lightweight devices and their integration have increased the requirements for materials, and two-dimensional composite multiferroic materials have become a major research hotspot in recent years. However, it is difficult for traditional solid multiferroic material to directly switch the magnetic/polarization direction under the action of an applied electric/magnetic field, limiting the improvement of the magnetoelectric coupling coefficient. In this study, a series of BiFeO 3 (BFO)/CoFe 2 O 4 (CFO) composite film multiferroic materials were prepared by changing the annealing routes and annealing atmosphere, the microstructure, ferroelectric properties, dielectric properties, photovoltaic properties, magnetic properties, and magnetoelectric coupling properties of composite films were routeatically studied. The results showed that under the slow annealing route, the composite film has obvious ellipsoidal grains with distinct grain boundaries and better crystallinity. Moreover, the performance of the film after annealing in different atmospheres of the slow annealing route was improved compared with that of the rapid annealing route after annealing in different atmospheres. Simultaneously, by changing the annealing atmosphere of the composite film, the film exhibited better magnetic optical properties and coupling properties after annealing in oxygen. In addition, this study showed that the dielectric constant and residual polarization value of the film increase under the action of magnetic field and illumination, and the maximum photomagnetic dielectric response (3.19%) and photomagnetic response (1.58%) are observed in the annealed film under the oxygen atmosphere of the slow annealing regime, indicating that the magnetoelectric coupling effect of the film is improved under the action of applied light. • Under the slow annealing system, the composite films have grain boundaries and better crystallinity. • The properties of the films annealed under the slow annealing regime are good under different atmospheres. • Films show better magnetic, optical and coupling properties after annealing in oxygen. • The dielectric constant and residual polarization of the film increase under the action of magnetic field and illumination. • Large photomagneto-dielectric responses (3.19%) and photomagneto-electric responses (1.58%) were observed. [ABSTRACT FROM AUTHOR]

ε-Fe 3 N can be flexibly synthesized via a sol-gel route by using ethylenediamine as the nitrogen source, and the role of ethylenediamine can be demonstrated by adjusting the molar ratio of ethanediamine to acetone. Excellent magnetic properties (72.35 emu/g) and coercivity are obtained at the optimized condition, showing the potential applications in magnetic material field. In addition, the probable formation mechanism of iron nitride is investigated in this article, supported by XRD patterns and etc, which has important effect on the further research of the iron nitride via a sol-gel route. [ABSTRACT FROM AUTHOR]

Ni doped Fe 3 C ((Fe 1−x Ni x ) 3 C) Nanoparticles (NPs) were prepared via a sol-gel method. The structure, morphology and magnetic properties of the materials are researched. Analysis results show that the crystallite size and magnetic parameters of the materials are affected by the Ni-dopant. Furthermore, it is also well investigated of the water purification for the mesoporosity, magnetic, high specific surface area and facile magnetic separation of the materials. The current synthetic approach is versatile and simple, and thus shows great promise for the large scale synthesis of Fe 3 C based NPs that are useful for water treatment such as the removal of organic molecules. [ABSTRACT FROM AUTHOR]

• (PLZT@SiO 2) core-shell structure ceramic materials are synthesized by the sol-gel combination with the solid-phase method. • Its dielectric constant can be adjusted by holding time. • The surface of PLZT coated with SiO 2 can increase the breakdown electric field (BDS) and thus increase the energy density. Antiferroelectric materials are considered promising energy storage materials because they have excellent energy density during the antiferroelectric phase transition. Herein, Pb 0.925 La 0.05 Zr 0.95 Ti 0.05 O 3 @SiO 2 (PLZT@SiO 2) core-shell structure ceramic materials were synthesized by combing sol-gel method with conventional solid-phase method. The effect of holding time (3 h, 6 h, 9 h, 12 h) on the electrical properties and energy storage properties of PLZT@SiO 2 ceramics were investigated. TEM results indicate the formation of a core-shell structure. Transmission electron microscope (TEM) reveals the formation of core-shell structure. X-ray diffraction (XRD) obtained clear tetragonal perovskite structure PLZT and SiO 2 phase. The phase transition temperature of PLZT@SiO 2 ceramics is between 222 °C and 225 °C, and its dielectric constant can be adjusted by the holding time. The PLZT with surface coated SiO 2 can increase the breakdown electric field (BDS) and thus increase the energy density. When the holding time is 9 h, the breakdown electric field is as high as 156.84 kV/cm, and the recoverable energy density (W re) is 1.92 J/cm3, which is mainly determined by its high density and breakdown electric field. [ABSTRACT FROM AUTHOR]

• The PLZT@SiO 2 composite ceramic was prepared by the Stöber method, which increased the density of the ceramic, and greatly improved the energy storage density. • SEM results indicate that SiO2 weakens the crystallinity of the ceramics and restricts the grain growth of all the specimens. • Compared with the single-phase PLZT ceramics, although the electric breakdown field strength of the core-shell structure sample has not improved much, its energy storage density has increased significantly. Pb 0.925 La 0.05 Zr 0.95 Ti 0.05 @ x wt%SiO 2 (PLZT@ x wt%SiO 2 , x = 0, 1, 2, 3 and 4, marked as S0, S1, S2, S3, S4 respectively) ceramics were prepared by combining conventional sol-gel method with Stöber method, the microstructure, electrical properties and energy storage characteristics were comparatively investigated. TEM analysis prove that samples S1, S2 and S3 present core-shell structures. SEM results indicate that SiO 2 weakens the crystallinity of the ceramics and restricts the grain growth of all the specimens. When the concentration of SiO 2 is 3 wt%, the sample shows better energy storage characteristics, the value of W re of this sample can reach 2.29 J/cm3; In addition, temperature (T) will induce a phase change in the sample. When T < 50 ℃, sample S3 is ferroelectric phase, when T is in the range of 50–130 ℃, sample S3 is coexistence of anti-ferroelectric and ferroelectric phase, showing double electric hysteresis loops. In this temperature range, the temperature stability of sample S3 is the poorest, and the increases in W re density and η are 317.39 % and 25.04%, respectively. The core-shell structure samples prepared by the Stöber method can increase the energy storage density by reducing the turnover electric field. The energy storage density has increased from 0.3 J/cm3 to 2.29 J/cm3. [ABSTRACT FROM AUTHOR]