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As an environmentally friendly thermoelectric material, SnSe has attracted great attention because of its excellent performance in its single-crystal form. On the other hand, the better mechanical property and lower manufacturing cost of its polycrystalline counterpart with the better mechanical property and lower manufacturing cost can serve as a better candidate for widespread applications. Previous reports on p-type polycrystalline SnSe mainly focus on optimizing the carrier concentration by doping alkali metals or decreasing the lattice thermal conductivity by nanostructuring. Here, we report the effect of Yb doping on the thermoelectric properties of polycrystalline SnSe prepared by solvothermal synthesis. Through introducing Yb, the p-type carrier concentration is increased and the density of states at valence band maximum is distorted, which is revealed by DFT calculation, leading to an increase of the effective mass. Thus, the power factor has been markedly enhanced to 0.78 mW m−1 K−2 at 823 K (about 1.6 times that of undoped SnSe). Moreover, Yb doping in SnSe decreases the lattice thermal conductivity by intensifying the phonon scattering. As a result, a high zT of 1.1 at 823 K in Sn 0.98 Yb 0.02 Se is achieved along the in-plane direction. This work provides a new way for improving the thermoelectric properties of SnSe by modifying its valence band structure. [Display omitted] • Yb doping reduced Sn vacancy formation energy in SnSe. • The density of states at valence band maximum is distorted after Yb doping, which caused an increase in effective mass. • Compared with pure SnSe, the power factor of 2%Yb-doped SnSe is increased by 60%, reaching 0.78 mW m−1 K−2 at 823 K. [ABSTRACT FROM AUTHOR]

Abstract: Simple laminate composite was prepared by bonding a Terfenol-D plate and a multilayer vibrator together. The composite enjoyed a high magnetic field sensitivity of 15nC/Oe at the magnetoelectric coefficient of 9.5V/(cmOe), which could detect 0.1mOe magnetic field. Giant converse magnetoelectric coefficient reached 46.5G/V for the whole sample and 74G/V at the middle of composite. These high qualities were achieved only with a Pb(Zr,Ti)O3 multilayer vibrator instead of Pb(Zr,Ti)O3 single-layer in the piezoelectric part due to its much large capacitance, large effective area and low thickness. This approach provides a promising application for the magnetoelectric materials. [Copyright &y& Elsevier]

Herein, a spray pyrolysis strategy for synthesizing clustered metal chalcogenides embedded in the hollow N -doped carbon framework is reported. After thermally induced sulfurization processes, ZnS/CoS/CoS 2 @N-doped carbon was successfully prepared as a novel anode for lithium-ion battery. Electrochemical evaluation revealed that the mixture exhibits a high initial discharge capacity of 1273.8 mA h g−1 reversible capacity of 622.7 mA h g−1 in the 200th cycle at a current density of 100 mA g−1. In addition, ZnS/CoS/CoS 2 @N-doped carbon hybrid composites also showed excellent rate capability (586.8, 492.2, 399.3 and 293.6 mA h g−1 at 200, 500, 1000 and 2000 mA g−1, respectively). Such findings provide a new solution to address volume expansion/shrinkage during the lithiation/delithiation cycles, which holds a great future for the design and manufacturing of high performance lithium-ion batteries. Image 1 • Developing advanced ZnS/CoS/CoS 2 @N-doped carbon nanoparticles anodes via industrially-viable synthetic approach. • The synthesis of nanostructured ZnS/CoS/CoS 2 @N-doped carbon nanoparticles is realized and the scheme was explored. • ZnS/CoS/CoS 2 @N-doped carbon nanoparticles shows great cycling stability and excellent rate capability for Li+ storage. [ABSTRACT FROM AUTHOR]

Tantalum-based perovskite-like metal oxides (PLMOs) are one of promising candidates for photocatalytic water splitting due to their high stability, structural tunability and excellent photocatalytic activity. However, the photocatalytic hydrogen production activity is often hampered by their narrow light absorption range and severe photo-generated carrier recombination. In this research, a series of Fe-doped KCuTa 3 O 9 (FKCTO-x) oxides were synthesized for the first time via one-step high-temperature solid-state reaction. Based on the detailed characterization analysis, Fe atoms have been successfully incorporated into the lattice of KCuTa 3 O 9. An extended visible light absorption range and enhanced separation of the photogenerated carriers have been achieved in Fe-doped KCTO. As a result, all the FKCTO-x samples exhibit enhanced photocatalytic hydrogen evolution activities, among which FKCTO-2 shows an optimal hydrogen production rate of 5.51 µmol h−1 under visible light irradiation, far exceeding that of the pure KCTO. This work provides a simple and effective strategy to design and prepare highly efficient visible-light-driven PLMOs for photocatalytic water splitting. [Display omitted] • A series of novel Fe-doped KCuTa 3 O 9 photocatalysts were synthesized successfully. • Fe atoms have been successfully incorporated into the lattice of KCuTa 3 O 9. • The extended visible light absorption range has been achieved in Fe-doped KCuTa 3 O 9. • The internal electric field helps the separation of photogenerated carriers. • The optimized FKCTO-2 shows an excellent photocatalytic H 2 production performance. [ABSTRACT FROM AUTHOR]

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]

In this paper, the synthesis of rare earth fluoride GdF 3 multiform morphologies via l -arginine hydrothermal method has been fulfilled for the first time. The size and shape of the products could be tuned just by adjusting the pH values of the initial reaction solutions. The morphologies for the products include submicron round disc, submicron flower disc, submicron rods and submicron bulks. Additionally, the possible formation mechanism of multiform morphologies was proposed. Furthermore, we systematically investigate the luminescence properties of different lanthanide ions (Tm 3+ , Dy 3+ , Eu 3+ ) in GdF 3 host. By adjusting their relative doping concentrations in the GdF 3 host, the different color hue of blue and yellow light are obtained by co-doped Tm 3+ ,Dy 3+ and Dy 3+ , Eu 3+ in GdF 3 host, respectively. Besides, there exist two energy transfer pairs in the GdF 3 host: (1) Tm 3+ →Dy 3+ ; (2) Dy 3+ →Eu 3+ . More significantly, in the Tm 3+ , Dy 3+ , Eu 3+ tri-doped GdF 3 phosphors, white light can also be achieved upon excitation of UV light by adjusting the doping concentration of rare earth ion (Tm 3+ , Dy 3+ , Eu 3+ ). Importantly, when the temperature was raised to 225 °C, the emission intensities of Dy 3+ (475 nm) and Eu 3+ (592 nm) was 65% and 71% of the initial value at 25 °C for GdF 3 : Dy 3+ , Eu 3+ , which indicating that the thermal stability of the phosphors of the GdF 3 :2%Dy 3+ , 3%Eu 3+ is excellent. In addition, the obtained samples also exhibit paramagnetic properties at room temperature (300 K). The result shows that the obtained nanophosphors have a promising application in display and lighting fields. [ABSTRACT FROM AUTHOR]

Sm 3+ doped TiO 2 nanocrystals with various morphologies were fabricated via a facile hydrothermal route, and the effect of morphology on the luminescence properties and photocatalytic activity of the products has been investigated. PL studies on TiO 2 :Sm 3+ revealed that the sensitized emission is a much more efficient pathway than the direct excitations of Sm 3+ . Combined 10 K spectra and theoretical analysis, several kinds of sites of Sm 3+ ions have been found in TiO 2 matrix. Most importantly, structural models for the formation of multiple sites are proposed based on the optical behaviors of Sm 3+ at different sites. Photocatalytic results suggest that flower-like hierarchical architectures show the highest photocatalytic activity compared with nanorods samples with different aspect ratios, and the photodegradation efficiency was 96.8% after 20 min for degradation of methyl orange under white light irradiation. And surface photovoltage spectroscopy (SPV) have been measured to understand the separation and transfer behaviour of photogenerated charges which are helpful for explaining the photocatalytic and luminescence properties deeply. Moreover, TiO 2 :Sm 3+ @TiO 2 luminescent enhancement homo-structures and TiO 2 :Sm 3+ @SiO 2 luminescent enhancement hetero-structures are prepared. The effect of calcination temperature on luminescence intensity and the luminescence enhancement mechanism have been discussed in detail. [ABSTRACT FROM AUTHOR]

Novel luminescent one-dimensional Ln 3+ (Eu, Tb) doped SiO 2 hollow nanofibers were successfully fabricated using a facile and economical co-axial electrospinning technique with subsequent calcination. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed that the as-obtained samples present obvious hollow morphology with an average diameter of 303 ± 11 nm and thin walls approximate 76 nm. For SiO 2 :xEu 3+ hollow nanofibers, the highest luminescence intensity, the longest lifetime and the largest quantum efficiency were both in the composition of 6 mol% Eu 3+ . The large value of R 21 indicated a highly disordered environment around Eu 3+ ions in the host, which was better for intense visible red emission. Meanwhile, the spectral characteristics and radiative properties were also analyzed according to the Judd-Ofelt theory from the emission spectra. What's more, under ultraviolet excitation, the emission colors of samples could be tuned from red to green, including bisque by doping Eu 3+ , Tb 3+ and co-doping Eu 3+ /Tb 3+ ions, which indicated the obtained SiO 2 :Ln 3+ hollow nanofibers are potential phosphors in nanostructured optical devices applications. [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]

The Mg 4 Nb 2 O 9 crystals grown by floating zone technology were used as prototypes to investigate optoelectronic parameters by measuring the absorption and transmittance spectra along the c -axis from 200 to 800 nm at room-temperature. The imaginary and real parts of the complex dielectric constants, extinction coefficient and refractive index for Mg 4 Nb 2 O 9 were obtained. The Cauchy–Sellmeier equation for Mg 4 Nb 2 O 9 was validated in the Urbach tail region (4.0–5.0 eV). The dispersion energy E d and oscillator energy E 0 were obtained via the single oscillator approximation. More interestingly, the self-trapped exciton and disorder of Mg 2+ and Nb 5+ between MgO 6 and NbO 6 octahedrons participating in the transition in the Urbach tail region were confirmed by the excitation spectrum. [ABSTRACT FROM AUTHOR]

ZnNb 2 O 6 single crystal grown via optical floating zone technology was selected as a prototype for optical phonon behavior investigation. Polarized Raman spectra were obtained in adequate parallel and crossed polarized configurations. All the obtained Raman modes were characterized for ZnNb 2 O 6 and were in good agreement with previous normal coordinate analysis. The selection rules for the columbite group were validated. The in-site temperature-dependent Raman spectra of columbite ZnNb 2 O 6 were also described, and the anharmonic interactions were discussed. [ABSTRACT FROM AUTHOR]

Abstract: The hydrothermal reaction of 2,5-pyridinedicarboxylic acid (H2PDC), diethylene triamine and In(NO3)3·4.5H2O gave rise to a two-dimensional (2D) coordination polymer In(OH)(2,5-PDC). This compound crystallizes in the orthorhombic space group Iba2, with cell parameters, a =12.656(3)Å, b =20.114(4)Å, c =6.2216(1)Å, V =1583.9(5)Å3 and Z =8. Its structure contains one-dimensional In–O–In–O– chains, which are further linked by 2,5-PDC ligands into a 2D supramolecular neutral framework. The adjacent 2D layers are parallel with each other and construct a three-dimensional framework via hydrogen bands. At room temperature, the compound exhibits intense photoluminescence. On the basis of the results of TG/DTA analyses, the structure is thermally stable up to ∼390°C. [Copyright &y& Elsevier]

The single-phase Ba 3 Sc(BO 3) 3 :Ce3+/Tb3+ samples were synthetized via high-temperature solid-state reaction. X-ray diffraction (XRD), Rietveld refinement and transmission electron microscopy (TEM) were used for characterizing the morphology and phase purity of Ba 3 Sc(BO 3) 3. The photoluminescence emission (PL) and excitation (PLE) spectra, lifetime decay behavior and thermal stability of the Ba 3 Sc(BO 3) 3 :Ce3+/Tb3+ phosphors were discussed in detail. Site occupation of Ce3+ ions in Ba2+ and Sc3+ sites were explained through Gaussian fitting and Van Uitert empirical equation. All these properties are closely related to the intrinsic crystallization structure of the Ba 3 Sc(BO 3) 3 matrix, which is discussed in detail in this paper. Compared with Ba 3 Sc(BO 3) 3 :1%Tb3+ sample, the luminous intensity of Tb3+ increased about 3.2 and 4.1 times for Ba 3 Sc(BO 3) 3 :2%Ce3+,1%Tb3+ monitored at 342 and 313 nm, respectively. Energy transfer (ET) mechanism of Ce3+→Tb3+ were dipole-dipole interactions and quadrupole-quadrupole interactions at Ce3+(1) and Ce3+(2) sites, respectively. The temperature-dependent PL spectra of Ba 3 Sc(BO 3) 3 : Ce3+,Tb3+ illustrated that this phosphor possesses excellent thermal stability and chromaticity stability. Finally, a white LED device was prepared via the combination of the n-UV chip (365 nm), commercial blue BAM:Eu2+ phosphor, green Ba 3 Sc(BO 3) 3 :2%Ce3+,6%Tb3+ phosphor and commercial red Sr 2 Si 5 N 8 :Eu2+ phosphor, which showed bright warm-white light. These conclusions proved that the green Ba 3 Sc(BO 3) 3 :2%Ce3+,6%Tb3+ phosphor is desirable for white LED applications. • Ce3+ ions occupied at Ba and Sc3+ sites for Ba 3 Sc(BO 3) 3 :Ce3+ emit blue light. • Broader absorption band (200–400 nm) matches well with the n-UV LED chips. • Decay curves prove the existence of multiple sites energy transfer of Ce3+.→Tb3+. • Color tuning from blue to green is successfully realized by the energy transfer. • Luminous intensity and thermal stability are increase. [ABSTRACT FROM AUTHOR]

Eu3+-activated AlN phosphors with hexagonal wurtzite structures were successfully prepared by a low-cost, nontoxic and simple solid-state route at 880 °C which is lower than many other synthesis temperatures. The structure and phase formation, morphology, elements analysis, photoluminescence and photocatalysis properties are investigated in detail. All the phosphors present red emission due to 5D 0 →7F 2 transition of Eu3+. The optimal doping concentration of Eu3+ in AlN matrix is 0.8% mole fraction, and the phosphors exhibit high color purity and high brightness. Meanwhile, AlN: x Eu3+ phosphors exhibit excellent photocatalytic hydrogen evolution activity, and the maximum rate of H 2 evolution from water splitting is 77 μmol h−1 g−1. These findings signify that bifunctional AlN:Eu3+ with photoluminescence and photocatalytic properties may be anticipated to apply in both white light-emitting diodes (WLEDs) and photocatalytic water reduction. Image 1 • AlN: Eu were prepared by a simple solid-state route. • Their structure, morphology and photoluminescence are detailedly investigated. • The photoluminescence properties of the materials are affected by the Eu doped concentration. • AlN: Eu exhibits excellent photocatalytic H 2 evolution activity, and is 77 μmolh−1g−1. [ABSTRACT FROM AUTHOR]