Simple Solid-state Reaction Method Research Articles

Tunable white-light emission and energy transfer in single-phase Bi3+,Eu3+ co-doped Ba9Y2Si6O24 phosphors for UV w-LEDs

In this paper, a series of Bi3+ and Eu3+ single-doped as well as Bi3+,Eu3+ co-doped Ba9Y2Si6O24 samples were synthesized through a simple high-temperature solid-state reaction method. Their crystal structures, morphologies, luminescent properties, temperature-dependent emission spectra, decay curves and quantum efficiencies were investigated in detail. Upon ultraviolet light excitation, Bi3+ single-doped samples exhibited blue and green emissions peaking at 408 and 501 nm, corresponding to the 3P1–1S0 transition of Bi3+ ions. The spectral analysis indicated that there were two different luminescent centers of Bi3+ ions due to different occupancies in Ba9Y2Si6O24 host lattice. And the highest quantum efficiency can reach 64.5% in Ba9Y2Si6O24:0.024Bi3+ phosphor. The remarkable spectral overlap between the emission spectra of Bi3+ ions and the excitation spectra of Eu3+ ions indicated the exist of energy transfer from Bi3+ to Eu3+. The efficient energy transfer from Bi3+ to Eu3+ has been investigated in detail and resulted in that tunable and white-light emission can be obtained by modulating Eu3+ doping concentration. White emission can be realized with the CIE coordinates of (0.357, 0.345) and quantum efficiency of 57.6% for Ba9Y2Si6O24:0.024Bi3+,0.02Eu3+. The above results demonstrate that Ba9Y2Si6O24:Bi3+,Eu3+ may be a potential candidate for ultraviolet (UV) driven white light-emitting diodes (w-LEDs).

Ni3(BO3)2 as anode material with high capacity and excellent rate performance for sodium-ion batteries

In this paper, Ni3(BO3)2 was synthesized via a simple solid-state reaction method and used as anode materials for sodium-ion batteries for the first time. The Ni3(BO3)2 exhibits a desodiation capacity of 428.9 mA h g−1 at 200 mA g−1 and a high capacity of 304.4 mA h g−1 even at 2000 mA g−1. The resulting material also shows a good cycling stability with a capacity retention of 85.4% over 50 cycles. In-situ X-ray diffraction analysis reveals the phase transition behavior of Ni3(BO3)2 in the first discharge process. Kinetics analysis reveals that the high-performance sodium storage is dominated by pseudocapacitance, especially at the high rate. These highlights indicate that Ni3(BO3)2 would have hopeful prospects as an anode material for sodium-ion batteries.

K-doped Na3Fe2(PO4)3 cathode materials with high-stable structure for sodium-ion stored energy battery

A novel NASICON-type K0.24Na2.76Fe2(PO4)3 (K0.24NFP) is synthesized via a simple solid-state reaction method. K-doped method can enlarge lattice distance and restrain the structure dilapidation from Na3Fe2(PO4)3 to Na5Fe2(PO4)3. Comparison with undoped-Na3Fe2(PO4)3 (NFP) sample (82.1 mAh g−1), K0.24NFP electrode shows a 101.3 mAh g−1 discharge capacity at 10 mA g−1, which up to 97% of theoretical capacity. As for rate capability performance, a high reversible capacity of 73.6 mAh g−1 at 1000 mA g−1. The cycle stability performance measurement results indicate that the discharge capacity of K0.24NFP electrode is up to 93.7 mAh g−1 after 500 cycles at 100 mA g−1. The excellent electrochemical performance is attributed to the improvement of structural stability and the highest intercalation-deintercalation kinetic of sodium-ions (DNa+ = 3.98 × 10−11) due to K-doped. Hence, the K-doped iron-based phosphate (K0.24Na2.76Fe2(PO4)3) should be a potential cathode material in sodium-ions batteries for scale energy storage.

Electrical properties of rare earth doped ceria electrolyte for solid oxide fuel cell applications

This paper attempt to investigate the structural and electrical properties of the boron doped Samarium doped Ceria (SDC) electrolyte prepared by simple solid state reaction method. The prepared sample was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and impedance Spectroscopy for their composition, size, and electrical conductivity. In this present work, we are evaluating the electrical conductivity of the prepared electrolyte. The sintered pellet exhibits good surface morphology. The frequency dependence of dielectric properties is obtained from impedance spectroscopy studies. Results of analysis reveal that nanocrystalline codoped sample was successfully prepared at low processing temperature with good ionic conductivity suitable for solid oxide fuel cell applications

Synthesis of an efficient lanthanide doped glass-ceramic based near-infrared photocatalyst by a completely waterless solid-state reaction method.

A novel efficient near-infrared photocatalyst of oxyfluoride glass-ceramic (Er3+/Yb3+-CaO-Al2O3-SiO2-CaF2)/TiO2 was synthesized by a simple solid-state reaction method, with optically active center (Er3+/Yb3+) doped CaF2 nanocrystals in glass-ceramic micro powders and nanosized anatase TiO2 as the superficial coating. This near-infrared photocatalyst preparation method has a high production efficiency with no wastewater generated.

Impact of activator incorporation on red emitting rods of ZnGa2O4:Cr3+ phosphor

Chromium doped zinc gallium oxide (ZnGa2O4:Cr3+) microrods were synthesized by simple solid state reaction method. The transformation on crystal structure and optical properties with molar concentration of Cr3+ were analyzed. The cubic spinel nature of ZnGa2O4:Cr3+phosphor and their crystalline nature were confirmed from x- ray diffractogram. The average grain size of the samples range between 24 and 29 nm, with lattice parameter values greater than that of bulk. Lattice strain produced in the lattice on doping was estimated from the Williamson–Hall plot. It increases on Cr3+ doping up to 3 mol% and then decreases. Rod like nature of zinc gallate was observed from the surface morphological analysis using SEM. X-ray photoelectron spectroscopy was used for the chemical state identification of the constituent elements in the compound. The photoluminescense spectra consists of various emission lines originated from the chromium ion in the spinel lattice. The purity of red emissions were observed from chromaticity diagram with a concentration quenching initiated from the dipole–dipole interaction, with increase in dopant concentration. Band gap of the samples were estimated using Kubelka-Munk equation which exhibited red shift compared to bulk due to band tailing effect.

3D interconnected architecture of h-BN reinforced ZrO2 composites: Structural evolution and enhanced mechanical properties for bone implant applications

The present investigation mainly focused on hexagonal boron nitride (h-BN) substitution for modified physical, mechanical and biological properties of nano zirconia (nZrO2).A simple and scalable solid-state reaction method has been used to prepare a three dimensional (3-D) composites in the system [(15+x)BN-(85-x)ZrO2] (0 ≤x ≤ 55). A major novel phase of zirconium oxynitrate, ZrO(NO3)2 was confirmed by X-ray diffraction(XRD) results. The uniform and interconnected distribution of large h-BN nanosheets ensure the significant grain refinement of nZrO2 established by surface morphology study of fabricated composites. This reinforcement of h-BN plays a pivotal role to enhance the ductility of zirconia. The composite sample 70B-30Z has a remarkable mechanical strength and less wear resistance as compared to the natural bone, for this sample (70B-30Z) various mechanical parameters i.e. Young’s modulus, fracture toughness, maximum mechanical strength, and density are found to be 9.84 MPa, 4.12 MPa m1/2, 174.94 MPa, and 2.54 g cm−3 respectively. The noteworthy cell proliferation at 25 µg/ml by MTT assay for the composite 70B-30Z recognizes it as a suitable bone implant material.

Effects of the synthesis conditions on the photocatalytic activities of sulfide-graphene oxide composites

Sulfide-graphene oxide composites photocatalysts were fabricated through a simple solid-state chemical reaction method under different synthesis conditions. The resulting photocatalysts were characterized by X-ray diffraction, transmission electron microscopy, Nitrogen adsorption-desorption specific surface areas, XPS measurements, UV–vis absorption spectroscopy, Transient photocurrent, and Photoluminescence spectra. The result suggests that ZnS and Bi2S3 nanoparticles well distributed on the graphene oxide nanosheets in the sulfide-graphene oxide composites. Nitrogen adsorption-desorption results indicate that the specific surface areas of the composites increased after the graphene oxide is introduced. XPS measurements suggest that there are interactions between sulfide and graphene oxide. The photocatalytic activities of sulfide-graphene oxide composites were measured by the degradation of methyl orange under UV irradiation. Variation of the synthesis conditions allowed the sulfide-graphene oxide composites possessing different structures and photocatalytic activities as revealed by transmission electron microscopy and photocatalytic measurements. The photocatalytic results indicated that the sulfide-graphene oxide composites exhibited much higher photocatalytic activities than that of pure ZnS and Bi2S3, and nearly 97% and 90% of methyl orange were degraded over ZnS-graphene oxide and Bi2S3-graphene oxide after irradiation for 120 min, respectively. The superior photocatalytic activities can be attributed to the high specific surface areas, which is benefical for improving photocatalytic reaction. Futhermore, introducing graphene oxide can effectively reduce the photoinduced electron-hole pair recombination probability, and then improve the photocatalytic activities, which have been proved by the transient photocurrent, photoluminescence spectra, and scavengers measurements.

Preparation, crystal structure and luminescence properties of red-emitting Lu3Al5O12: Mn4+ ceramic phosphor

A series of red-emitting Mn4+ doped Lu3Al5O12 (LuAG) ceramic phosphors were successfully prepared by a simple solid-state reaction method in a high-temperature muffle. MgO was co-doped as sintering aids and Mg2+ ions helped to realize the charge balance. The relations between the luminescence properties, crystal structures and the microstructures were well established. Results indicated that MgO promoted the densification of the ceramics as the specimens’ relative densities were up to 99%. Moreover, the substitution of Al3+ with Mg2+ have changed crystal structures and further affected the luminescent properties. Overall, the obtained ceramic phosphors showed strong red-light emission under excitation of ultraviolet and blue light. By optimizing the Mg2+ and Mn4+ concentration, a quantum efficiency (QE) as high as 47.8% can be achieved under the excitation of 460 nm light, indicating that the LuAG: Mn4+ ceramic phosphors are promising candidates for WLEDs applications.

Sulfur Doped Lead Monoxide Superfine Powder Materials: Solid-State Synthesis, Characterization, Adsorption and Photocatalytic Property of Methylene Blue

Sulfur doped lead monoxide (S–PbO) superfine powder materials with high visible light-driven activity were successfully prepared by a simple solid-state reaction method at low temperature using sodium dodecyl benzene sulfonate (SDBS) as a template. The samples were characterized by X-ray powder diffraction, high resolution transmission electron microscopy/energy-dispersive X-ray spectroscopy, UV–Vis absorption spectra, infrared spectroscopy, X-ray photoelectron spectroscopy and N2 adsorption–desorption. The effect of feed ratio on the microstructure of materials, the doping mechanism of sulfur and the adsorption mechanism of methylene blue (MB) on the material surface were discussed. In addition, the intrinsic relationships among the material structure parameters, the photocatalytic degradation of MB under visible light irradiation and the stability of materials were investigated. The results show that the S element is successfully incorporated into the (111) crystal plane of the orthorhombic β-PbO lattice as a S(IV) and S(VI) at the assistance of SDBS. The content of sulfur has a certain regulatory effect on the energy gap of the orthorhombic PbO, and there is a positive correlation among the photocatalytic property of MB, the content of sulfur, and the lattice spacing of (111) and (310) crystal plane. The adsorption of MB mainly depends on the interaction between the surface active sites (S–O bond) and hydroxyl groups, and the adsorption relaxation time under different sulfur content. Under visible-light irradiation at room temperature within 60 min, the photocatalytic degradation (wt%) rate of MB (C0 = 50 mg/L) follows an order of S–PbO(S:Pb = 0.05:0.95) (97.8%) > S–PbO(S:Pb = 0.10:0.90) (90.6%) > S–PbO(S:Pb = 0.15:0.85) (83.5%) > S–PbO(S:Pb = 0.20:0.80) (72.3%) > PbO (48.2%). The holes (h+) and hydroxyl radicals (·OH) are the main active species during the photodegradation of MB solution for the S-doped PbO materials. The S-doped PbO materials are of a p-type indirect semiconductor, and the loss of lead is very little in the MB solution, it is feasible to the S-doped PbO powder materials as photocatalysts.

Suitability of Pr2–xCaxNiO4+δ as cathode materials for electrochemical devices based on oxygen ion and proton conducting solid state electrolytes

In order to develop economically competitive solid oxide fuel cell (SOFC) systems it is necessary to design new functional materials with the purpose of enhancing their performance, extending operational lifetime and reducing the cost. The present work focuses on the study of Pr2-xCaxNiO4+δ cathode materials prepared by a simple and cheap conventional solid state reaction method. The structure, oxygen nonstoichiometry, electrical properties and chemical compatibility of the materials with a number of well-known oxygen ion and proton conducting electrolytes were systematically investigated. Chemical composition (Ca content) and technological factors (powders pre-history, electrodes' sintering temperature), as well as external parameters (temperature, air humidity) were correlated with the electrochemical performance of the electrodes to determine the optimal compositions and conditions. Based on this study and testing results of the single anode-supported cell with BaCe0.89Gd0.1Cu0.01O3-δ electrolyte, the Pr1.7Ca0.3NiO4+δ-based electrode compositions are proposed for preferred usage in SOFCs in place of Pr2NiO4+δ electrode.

Facile and efficient room temperature solid state reaction enabled synthesis of antimony nanoparticles embedded within reduced graphene oxide for enhanced sodium-ion storage

Herein, a very simple and cost-effective solid state reaction method is employed to obtain, for the first time, the antimony nanoparticles embedded within reduced graphene oxide matrices (designated as Sb/rGO). By directly grinding antimony chloride and sodium hydroxide together at room temperature in the presence of graphene oxide (GO), Sb4O5Cl2 precursor was quickly obtained, which is evenly incorporated in the graphene oxide matrices. After subsequent chemical reduction by NaBH4, the Sb/rGO composite was successfully synthesized. The as-prepared Sb/rGO composite consists of uniform Sb nanoparticles of sub-20 nm, all of which have been wrapped in and protected by the rGO matrices. The Sb nanoparticles serve as a sufficient sodium ion reservoir while the rGO matrices provide highly efficient pathways for transport of sodium ions and electrons. Moreover, the volume expansion of Sb during sodiation can be buffered in the rGO matrices. As a result, the Sb/rGO composite exhibits excellent electrochemical performance in sodium-ion batteries (SIBs), including an enhanced cycling stability with a highly reversible charge capacity of 455 mA h g−1 after 45 cycles at 100 mA g−1, and a coulombic efficiency exceeding 98% during cycling. The findings in the present work pave the way to not only synthesize the designated promising electrode materials for high performance SIBs, but also thoroughly understand the solid-state reaction.

Improving electrochemical performance by Na, Mg and Al-ion doping of PbLi2Ti6O14 as anode materials for Li-ion batteries

In recent years, titanium-based oxides have attracted great attention in the research field of secondary Li-ion batteries. However, they suffer from poor electronic conductivity due to a huge band gap. In this paper, PbLi2Ti6O14 is fabricated by a simple one-step solid-state reaction method. To enhance its conductance and Li-storage capability, PbLi1.95Na0.05Ti6O14, PbLi1.95Mg0.05Ti6O14 and PbLi1.95Al0.05Ti6O14 are fabricated by Na, Mg and Al-ion doping. More impressively, PbLi1.95Al0.05Ti6O14 presents a superior reversible capability with a reversible charge capacity of 152.8mAhg−1 after 100 cycles at current density 100mAg−1. In addition, it also clearly demonstrates that PbLi1.95Al0.05Ti6O14 has good structural stability and electrochemical reversibility by in situ XRD observation. Besides, it also presents a high Li-ion diffusion coefficient of 1.978 × 10–12cm2s−1. All of these make it possible to become a superior performance anode material for Li-ion batteries.

Superlattice-like structure and enhanced ferroelectric properties of intergrowth Aurivillius oxides.

Aurivillius oxides with an intergrowth structures have been receiving increasing interest because of their special structures and potential outstanding ferroelectric properties. In this work, Bi3LaTiNbFeO12–Bi5Ti3FeO15 and Bi3TiNbO9–Bi3LaTiNbFeO12 compounds were successfully synthetised using a simple solid-state reaction method. X-Ray diffraction patterns and scanning transmission electron microscopy high angle annular dark field (STEM-HAADF) images confirm the 2–3 and the 3–4 intergrowth structures in Bi3TiNbO9–Bi3LaTiNbFeO12 and Bi3LaTiNbFeO12–Bi5Ti3FeO15 compounds, respectively. A superlattice-like distortion in these oxides was proposed resulting from the combination of sub-lattices with different a and b parameters, which was validated by XRD refinements and Raman spectra. Polarization-electric field tests and pulsed polarization positive-up negative-down measurements demonstrate that such superlattice-like structures can effectively enhance the intrinsic ferroelectric polarization and coercive field of these oxides, especially when compared with their component oxides Bi3TiNbO9, Bi3LaTiNbFeO12 and Bi5Ti3FeO15. Simultaneously, ferroelectric Curie temperatures of Bi3TiNbO9–Bi3LaTiNbFeO12 and Bi3LaTiNbFeO12–Bi5Ti3FeO15 oxides are lowered because of the internal stress in the superlattice-like structure. Nevertheless, the paramagnetism of the samples is hardly influenced by their structure, while mainly related to their iron content, in which iron has a similar effective magnetic moment around 3.4–3.9.

Intense and color-tunable upconversion luminescence of Er3+ doped and Er3+/Yb3+ co-doped Ba3Lu4O9 phosphors

A series of novel Er3+ doped and Er3+/Yb3+ co-doped Ba3Lu4O9 phosphors were synthesized by a simple high-temperature solid-state reaction method. The crystal structure and morphology of the samples were identified by XRD and SEM analysis. Under 980 nm laser diode excitation, the green (at 537 nm and 560 nm) and red (at 660 nm) UC emission were observed, which could be attributed to the (2H11/2, 4S3/2)→4I15/2 and 4F9/2 → 4I15/2 transitions, respectively. The UC luminescence can be finely tuned from green to dark-yellow light to some extent by increasing Yb3+ doping concentration. The sintering temperature and doping concentration of Ba3Lu4-x-yO9: x Er3+, y Yb3+ were optimized to x = 0.1 and y = 0.6 at 1550 °C. The emission intensity ratio of Green/Red keeps declining monotonically with increasing Er3+ or Yb3+ concentration, which is due to the cross-relaxation effect and cooperative energy transfer between the two neighboring Er3+ ions-as well as back energy transfer from Er3+ to Yb3+ ions. Based on the pump-power dependence and UC luminescence decay curves, the energy level diagram and the possible energy transfer mechanism of Er3+ doped as well as Er3+/Yb3+ co-doped system were investigated in detail. In addition, according to the energy gap law, the possibilities of non-radiative transition between parts of energy levels of Er3+ ions were calculated.

Synthesizing nonstoichiometric Li3−3xV2+x(PO4)3/C as cathode materials for high-performance lithium-ion batteries by solid state reaction

A simple solid state reaction method has been developed to synthesize nonstoichiometric Li3−3xV2+x(PO4)3/C (x = 0–0.15) nanocomposites.

Easy synthesis and electric, magneto-transport and magnetic properties of double perovskite La2CoMnO6 compound

We report synthesis of double perovskite La2CoMnO6 compound by a simple solid state reaction method. The samples sintered at different temperatures showed single phase nature with monoclinic P21/n space group. The phase purity was confirmed through the presence of characteristic Raman scattering modes. The samples exhibited semiconducting behavior without any anomaly in the temperature range 125 K ≤ T ≤ 300 K. The maximum magnetoresistance value at low temperature was around 40 %. The electric and magneto-transport behaviors were governed by variable range hopping mechanism. A single paramagnetic to ferromagnetic transition and well saturated hysteresis loops, indicative of ordered phase were observed in these samples.

Microstructure, ferromagnetic and photoluminescence properties of ITO and Cr doped ITO nanoparticles using solid state reaction

Indium-tin-oxide (ITO) (In0.95Sn0.05)2O3 and Cr doped indium-tin-oxide (In0.90Sn0.05Cr0.05)2O3 nanoparticles were prepared using simple low cost solid state reaction method and characterized by different techniques to study their structural, optical and magnetic properties. Microstructures, surface morphology, crystallite size of the nanoparticles were studied using X-ray diffractometer (XRD), field emission scanning electron microscope (FE-SEM). From these methods it was found that the particles were about 45nm. Chemical composition and valence states of the nanoparticles were studied using energy dispersive analysis of X-rays (EDAX) and X-ray photoelectron spectroscopy (XPS). From these techniques it was observed that the elements of indium, tin, chromium and oxygen were present in the system in appropriate ratios and they were in +3, +4, +3 and −2 oxidation states. Raman studies confirmed that the nanoparticle were free from unintentional impurities. Two broad emission peaks were observed at 330nm and 460nm when excited wavelength of 300nm. Magnetic studies were carried out at 300K and 100K using vibrating sample magnetometer (VSM) and found that the ITO nanoparticles were ferromagnetic at 100K and 300K. Where-as the room temperature ferromagnetism completely disappeared in Cr doped ITO nanoparticles at 100K and 300K.

Effect of Co and Ni codoping on the structural, magnetic, electrical and optical properties of ZnO

Co and Ni codoped ZnO-based dilute magnetic semiconductors having a general formula of Zn0.9Co0.1−xNixO (x=0.0, 0.02, 0.04, 0.06, 0.08 and 0.10) have been prepared using a simple solid-state reaction method. A single-phase hexagonal wurtzite structure, confirmed by X-ray diffraction, has been developed for Zn0.9Co0.1−xNixO (x<0.05), while minor secondary peaks of NiO were detected in samples having x=0.06, 0.08 and 0.10. The study of surface morphology revealed grain sizes in the range of 1.41–0.71μm. Raman spectra in the 200–800cm−1 range have been studied. The direct band gap energy for all the samples was found to be less than that of pure ZnO. Fourier transform infrared spectroscopy and UV–vis spectroscopy confirmed the incorporation of the Co and Ni ions into a ZnO lattice. Magnetic characterisation performed by vibrating sample magnetometer exhibited room-temperature ferromagnetism. Temperature-dependent electrical resistivity measurements were performed using a four-point probe technique.

Evaluation of the electrochemical behavior and structural reversibility of Li3−xNaxV2(PO4)3/C (0≤x≤3) as anode materials for Na-ion batteries

A series of Li3−xNaxV2(PO4)3/C (0≤x≤3) materials are successfully prepared by a simple solid-state reaction method and used for the first time as anode materials for Na-ion batteries. Powder X-ray diffraction (XRD) results show that the phase structures of Li3−xNaxV2(PO4)3/C evolve along with the change of Li/Na atomic ratio (0≤x≤3). With increasing x in Li3−xNaxV2(PO4)3/C from 0.0 to 3.0, the main phase in as-prepared sample transforms from monoclinic Li3V2(PO4)3 to rhombohedral Li3V2(PO4)3, and finally to rhombohedral Na3V2(PO4)3, which results in different sodium storage behavior and performance between Li3−xNaxV2(PO4)3/C (0≤x≤3) materials. Electrochemical results show that Li3−xNaxV2(PO4)3/C (x=0.0, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0) can deliver the initial charge capacities of 21.1, 35.9, 33.8, 41.7, 43.3, 43.9 and 47.7mAhg−1 at a current density of 10mAg−1, respectively. After 45 cycles, the reversible capacities can be kept at 16.9, 45.1, 32.6, 44.6, 43.7, 37.8 and 27.3mAhg−1 for Li3V2(PO4)3/C, Li2.5Na0.5V2(PO4)3/C, Li2NaV2(PO4)3/C, Li1.5Na1.5V2(PO4)3/C, LiNa2V2(PO4)3/C, Li0.5Na2.5V2(PO4)3/C and Na3V2(PO4)3/C, respectively. Furthermore, the structural reversibility of Li3−xNaxV2(PO4)3/C (x=1.0, 2.0, and 3.0) is also observed by in-situ XRD observation during sodiation/de-sodiation process. All these observed evidences indicate that only some of Li3−xNaxV2(PO4)3/C (0≤x≤3) can be used as possible sodium storage materials.