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Eu3+ activated red phosphors based on the CaY x (MoO 4) 1.5x+1 (x = 0.2, 0.4, 0.6, 1, 2) as host materials were synthesized by using a combustion method. XRD analysis demonstrated that the synthesized samples matched with the standard card CaMoO 4 (JCPDS NO.77-2239) belonging to the tetragonal of the I4 1 /a space group. All samples showed several narrow sharp emission peaks under 393 nm n-UV excitation, the strongest of which was at 618 nm attributed to the 5D 0 →7F 2 transition of Eu3+. The optimal composition of the host was found to be CaY 0.6 (MoO 4) 1.9 (hereafter referred to as CYMO). After doping Sm3+ into CYMO:Eu3+ phosphor, the absorption peaks of Eu3+ at 393 and 464 nm were broadened, and the peak intensity was also significantly higher than that of single-doped Eu3+. The energy transfer phenomenon between Sm3+ and Eu3+ was discovered by the excitation and emission spectra in CYMO:Eu3+,Sm3+ phosphors, and verified by the fluorescence lifetime of Sm3+ ions in the phosphors. The energy transfer mechanism between Sm3+ and Eu3+ is a dipole-dipole interaction, where the energy transfer efficiency in CYMO phosphor doped with 13% Eu3+ and 3% Sm3+ is 17.9%. The CIE coordinate and color purity were calculated as (x = 0.6598, y = 0.3388) and 93.72%, which indicated that the CYMO:13%Eu3+,3%Sm3+ phosphor is a red phosphor with excellent performance for potential application in n-UV light excited w-LEDs. [ABSTRACT FROM AUTHOR]

In this study, a series of white light-emitting NaSrVO 4 :Dy3+ phosphors with La3+ co-doping were produced by a combustion method. The configurations of the as-prepared NaSrVO 4 :Dy3+ and NaSrVO 4 :Dy3+, La3+ specimens are consistent with the standard phase of NaSrVO 4. The impacts of the Dy3+ concentration and La3+ co-doping on the luminescence characteristics of NaSrVO 4 : Dy3+ phosphors were explored. The specimens excited by near-ultraviolet light displayed emission peaks at 580 (yellow) and 484 nm (blue), which were ascribed to the 4F 9/2 → 6H 13/2 and 4F 9/2 → 6H 15/2 transitions of the Dy3+ ions, respectively. The white light was manufactured by these two emissions from the NaSrVO 4 : Dy3+ phosphor. Photoluminescence studies demonstrated that the La3+ co-doping efficiently improved the luminescence characteristics of the NaSrVO 4 : Dy3+ phosphor. These results suggest that the NaSr 0.9425 VO 4 : 0.05Dy3+, 0.0075La3+ phosphors excited by near-ultraviolet are promising materials for white light-emitting diodes. [ABSTRACT FROM AUTHOR]

The heavy metals and organic substances has deterioration of the ecosystem, resulting in serious environmental pollutions, thus urgent solutions need to be developed in treating these waste water problems. Functional compounds modified 3D polyurethane foams, with high surface to volume ratio has paid much attentions due to their high efficiency of absorption capability. In this study, polyethyleneimine (PEI) was used to incorporated into polyurethane foam (PUF) loaded with sodium carboxymethylcellulose (SCMC), resulting in a cross-linked, 3D interconnective porous polyurethane foam (PCPUF). The results of adsorption experiments demonstrated that PCPUF exhibited a strong adsorption capacity for both MO and Cd2+, with corresponding maximum adsorption capacity of 415.198 mg/g (at 328 K, pH 7) and 166.48 mg/g (at 343 K, pH 7), respectively. Furthermore, the results of cyclic adsorption experiments showed that the removal rates of MO and Cd2+ after five cycles are 90 % and 85 %, respectively, indicating that PCPUF has a good recyclability. Therefore, 3D porous polyurethane foams show promise as an effective adsorbent for removing metal ions and organic substances. [Display omitted] [ABSTRACT FROM AUTHOR]

Adsorption is a simple and efficient phosphorus removal method used to control the eutrophication of water bodies. A simple and gentle atmospheric pressure hydrothermal method by adjusting the dosage of ammonium chloride and sodium hydroxide was used to synthesize amorphous, monoclinic, and tetragonal zirconia nano-powders with high specific surface areas (383.91 m2/g, 330.01 m2/g, and 234.36 m2/g) and particle size of about 40 nm for phosphate adsorption. When pH = 6.3, the phosphate adsorption capacity of the amorphous monoclinic phase and the tetragonal phase respectively reached 102.58 mg P/g, 68.11 mg P/g, and 37.25 mg P/g and the adsorption process of the three crystal forms of zirconia powders conformed to the Langmuir adsorption model. In the first 2 min of rapid adsorption, amorphous zirconia completed 76.23% of the adsorption process and the monoclinic phase also completed more than 60%. The adsorption process of the three crystal forms of zirconia was completed within 240 min and conformed to the pseudo-second-order kinetic model. Their adsorption characteristics of the three crystal forms of zirconia decreased with the increase in pH. While the pH was above than the isoelectric point of the solution, the adsorption capacity was significantly reduced. The large specific surface area and high hydroxyl content of the zirconia nano-powder made a great contribution to the adsorption process. [ABSTRACT FROM AUTHOR]

The stability of phosphors and matrix under humid conditions and elevated temperatures is essential for the stable performance of light-emitting diodes. We synthesized a series of NaYSiO 4 : x Eu3+ (x = 0.00–0.14) phosphors via a sol-gel reaction. The NaYSiO 4 crystallizes in a hexagonal structure (space group P63/m) with a bandgap value of 4.60 eV. In this lattice, doped Eu3+ occupied the center of non-inversion symmetry. Under the optimal 394 nm excitation, the NaYSiO 4 :0.04Eu3+ sample showed a strong red emission at 618 nm with a high color purity of up to 94.98 %. Impressively, it exhibited high thermal stability (523 K, > 50 %, ∆ E = 0.24089 eV) and moisture resistance. Due to the protection of the stable coordination environment provided by cyclic Si-O-Si bands and strong binding energy, it retained 90.2 % of its original intensity after exposure under the relative humidity of 85 % at 85 °C for 240 h. Furthermore, this red phosphor was packaged into a cold white light-emitting diode with Commission International de l′Eclairage (0.3250, 0.3364). From the perspective of host lattice structure, this work provides a new strategy to withstand luminous degradation under humid and warm conditions. • NaYSiO 4 :Eu3+ exhibits excellent moisture resistance and thermal stability. • NaYSiO 4 :Eu3+ is an effective red-emitting component with high color purity. • Eu3+ occupies non-inversion symmetry sites protected by Si-O-Si bands. [ABSTRACT FROM AUTHOR]

To improve the luminescence property of Sm3+ in Y 2 Mo 3 O 12 , partial Ca2+-F- co-substituted Y 2 Mo 3 O 12 :Sm3+ phosphor, namely Y 2- x Ca x Mo 3 O 12- x F x :Sm3+, was prepared using a solid-state method. The effect of introducing Ca2+-F- ion pairs on structure and luminescence properties of Y 2 Mo 3 O 12 :Sm3+ was studied in depth. XRD patterns not only manifested that all as-prepared Y 2- x Ca x Mo 3 O 12- x F x :Sm3+ samples had standard Y 2 Mo 3 O 12 structure, but also indicated the introduction of Ca2+-F- ion pairs did not cause the change of crystal structure. Under the near ultraviolet excitation of 404 nm, the emission peaks of Y 2 Mo 3 O 12 :Sm3+ were located at 567 nm, 605 nm and 652 nm, respectively, resulting from the 4f→4f electron transitions of Sm3+ ions. Furthermore, the luminescence intensity of Sm3+ was obviously enhanced through the co-substitution of Y3+-O2- ions with Ca2+-F- ions in Y 2 Mo 3 O 12 structure, and the chromaticity coordinates moved towards red region, which due to the environmental effect of crystal field around Sm3+. Besides, the red LED device was manufactured for suitable chromaticity parameters. All results indicated that the as-prepared Y 1.84 Ca 0.06 Mo 3 O 11.94 F 0.06 :0.10Sm3+ red-emitting phosphor could become a promising candidate for application of white light-emitting diodes and plant illumination. [ABSTRACT FROM AUTHOR]

A series of β -Ca 3 (PO 4) 2 type single-component Ca 19 Zn 2 (PO 4) 14 :Dy3+, M+ (M = Li, Na and K) white-emitting phosphors were synthesized via a high-temperature solid-state reaction method, where alkali metal ions (M+) co-doped as charge compensator into the Ca 19 Zn 2 (PO 4) 14 :Dy3+ phosphor was aimed at improving the overall luminescence. The influences of synthesis temperature and the M+ introduction on both structure and luminescence property were thoroughly studied. X-ray diffraction patterns verify that the as-prepared phosphors attain the standard Ca 19 Zn 2 (PO 4) 14 phase without impurities. Photoluminescence peaks at 484 nm and 575 nm (originating from the 4F 9/2 → 6H 15/2 and 4F 9/2 → 6H 13/2 electron transitions of Dy3+ ions) were produced for all samples with an excitation of 386 nm, which then combined to emit white light. The luminescence intensities of Ca 19 Zn 2 (PO 4) 14 :Dy3+ were dramatically improved through co-doping with M+ into the phosphor structure. These results demonstrate the promising application prospects of Ca 19 Zn 2 (PO 4) 14 :Dy3+, M+ white-emitting phosphors in white light-emitting diodes. [ABSTRACT FROM AUTHOR]

A series of Cd 2 V 2 O 7 :Eu 3+ , Li + red phosphors was prepared by a solid-state reaction method. A pure Cd 2 V 2 O 7 phase with monoclinic structure was obtained by heating to a temperature range of 600–850 °C. The effects of Eu 3+ doping and Li + co-doping concentrations on the luminescence properties of Cd 2 V 2 O 7 :Eu 3+ , Li + samples were investigated. Under excitation at 375 nm, the as-prepared Cd 2 V 2 O 7 :Eu 3+ phosphors exhibit a red emission peak at 618 nm due to the 5 D 0 → 7 F 2 electronic transition of Eu 3+ . The luminescence properties of Cd 2 V 2 O 7 :Eu 3+ , Li + samples are improved significantly by the addition of Li + as charge compensator compared to the Cd 2 V 2 O 7 :Eu 3+ phosphor. The results indicate that Cd 2 V 2 O 7 :Eu 3+ , Li + phosphor could be a promising red phosphor in near ultraviolet-excited white light-emitting diodes for warm white light. [ABSTRACT FROM AUTHOR]

A series of Eu 3+ -doped C 12 H 18 Ca 3 O 18 phosphors were synthesized through a facile hydrothermal method and the properties of as-prepared phosphors were explored by X-ray diffractometer (XRD), scanning electron microscope (SEM), and photoluminescence (PL) spectrometer. The exploration results indicated that the C 12 H 18 Ca 3 O 18: Eu 3+ had been successfully synthesized. The morphology of C 12 H 18 Ca 3 O 18: Eu 3+ was a strip with the size of 100–4000 nm × 50–400 nm × 50–200 nm and the ratio of length to width of 2–80. The strongest emission peak of C 12 H 18 Ca 3 O 18: Eu 3+ around 620 nm was ascribed to 5 D o → 7 F 2 transition of Eu 3+ , and the peaks centered at 590, 653 and 694 nm respectively corresponded to 5 D o → 7 F 1 , 7 F 3 , and 7 F 4 transitions. C 12 H 18 Ca 3 O 18: Eu 3+ gave the red light emission, as indicated by color coordinate analysis. The photoluminescence intensity of the phosphors prepared under the Eu 3+ concentration of 6% was the highest. The crystal structure of C 12 H 18 Ca 3 O 18: Eu 3+ was changed after europium ions occupied the lattice position of calcium ions. Europium ion could displace calcium arbitrarily. As a new kind of matrix, calcium citrate possesses the properties of both organic and inorganic compounds and the luminescent C 12 H 18 Ca 3 O 18 : x Eu 3+ particles may be applied in biological fluorescent tags and luminescent materials. [ABSTRACT FROM AUTHOR]

In order to solve the pollution of heavy metals and organic antibiotic in the water environment, a novel CuBi 2 O 4 /calcined ZnAlBi layered double hydroxides (CBO/CLDHs) composite was constructed and prepared via an ultrasonic-assisted calcination method for the adsorption and photocatalysis synergetic effect. Through varying the composition ratio, pH value, initial pollutant concentration and other pollutant interference, the simultaneous removal ability including adsorption and photocatalysis of as-prepared CBO/CLDHs composites for Cr(VI) and tetracycline pollutants was discussed. In particular, the CBO/CLDHs-1/15 composite showed that the removal efficiencies of Cr(VI) (40 mg/L) and tetracycline (40 mg/L) were both above 95%. Meanwhile, the XPS results confirmed that the toxic Cr(VI) was gradually reduced to non-toxic Cr(III) under visible light irradiation. The enhanced adsorption and photocatalytic activity was mainly attributed to the uniform distribution of calcined ZnAlBi layered double hydroxides nanosheets on the CuBi 2 O 4 microrods and the formation of heterojunctions. Moreover, cycle performance results revealed that the CBO/CLDHs-1/15 composite maintained high removal activity and stable structure after 4 photocatalytic cycles, and even showed a good adaptability while applied to the actual water in production and living environments. These results exhibited that the as-prepared CBO/CLDHs-1/15 composite has excellent adsorption and photocatalytic ability for the simultaneous removal of Cr(VI) and tetracycline, with a great potential application in practical waste water treatment field. [Display omitted] [ABSTRACT FROM AUTHOR]

Degradable scaffolds with high porosity, certain mechanical and shape memory properties and biocompatibility are ideal materials in the field of bone tissue engineering for minimally invasive surgical implantation methods. In this study, we prepared porous scaffolds using hydrophilic polyethylene glycol and degradable polycaprolactone as raw materials and calcium citrate/amorphous calcium phosphate as hybrid particles, via sequential gas foaming, salt leaching and freeze drying methods. The fabricated bone scaffold exhibited adjustable mechanical properties and pore structure, with high shape fixation (>94.5%) and shape recovery (>87%) in thermal cycling and excellent shape memory properties under simulated body fluid immersion near body temperature. Moreover, in cell proliferation and live/dead cell activity assay experiments, the scaffolds promoted the proliferation of mesenchymal stem cells (MSCs). Immunofluorescence staining assay experiments further showed that the scaffolds had strong expressions of human type Ⅰ collagen (Col I) and alkaline phosphatase (ALP) in bone matrix. The material is expected to be a potential alternative material for bone tissue engineering. Smart foams recovered from squeezed shape to porous shape under thermal condition with well distribution of CA particles. [Display omitted] [ABSTRACT FROM AUTHOR]

A convenient and effective method was developed to fabricate zirconium-based calcium sulfate whiskers (Zr-CSWs), an environmentally friendly adsorption material designed to clean excessive fluoride from wastewater. Zr-CSWs, which potentially provide high adsorption activity toward fluoride in wastewater, overcome an aggregation problem typical of Zr-based species that may block the pore structure of the supporting material and degenerate its treatment performance. The results indicate that Zr-CSWs show excellent equilibrium adsorption capacity compared to other Zr-based materials in practical water solutions with pH values of 6–7. The adsorption of fluoride on Zr-CSWs was further evaluated in accordance with the Langmuir equation and the pseudosecond-order model. Coexisting anions had a minor effect on the removal of fluoride, and a strong alkali solution regenerated the used adsorbent. Density functional theory (DFT) calculations were performed to determine the mechanism of fluoride removal. The calculations demonstrated that the removal of fluoride by Zr-CSWs was mainly achieved by ion exchange between fluoride ions and OH- on the surface of the adsorbent, where a protonation process created low-coordination Zr atoms. [Display omitted] • Zirconium decorated calcium sulfate whisker (Zr-CSW) was prepared in a simple and low-cost way. • Zr-CSW has high capacity and good selectivity for the removal of fluoride in water. • The adsorption follows Langmuir model and pseudosecond-order dynamic equation. • The mechanism for fluoride removal has been revealed by density of functional theory (DFT). [ABSTRACT FROM AUTHOR]

• Glass with a high vanadium content improved the migration efficiency of Li+. • Adding Fe 2 O 3 stabilized the structure and increased the contents of V3+ and V4+. • The cathode has the outstanding specific capacity and high-current response. Among new lithium-ion battery cathode materials, amorphous materials show unique advantages and vanadium-based materials are potential electrode materials. In our study, the vanadium-based Li 2 O-V 2 O 5 -B 2 O 3 glassy state electrode materials with high vanadium contents were prepared in air by the melt-quenching method. The structures and electrochemical performances of glass materials were investigated by various characterization methods. The Li 2 O-V 2 O 5 -B 2 O glass were mainly connected with VO 4 and BO 3 structural units to form a disordered network structure. The first discharge capacity of 20Li 2 O-60 V 2 O 5 -20B 2 O 3 glass cathode material reached 168.6 mAh/g at a current density of 100 mA/g. The conversion of V3+/V4+ and V4+/V5+ mainly occurred in the charge and discharge cycles. When 10% of B 2 O 3 was replaced by Fe 2 O 3 , the compactness and stability of the material were improved. Furthermore, with the addition of Fe 2 O 3 , the concentrations of low-valence V4+, V3+ and Fe2+ ions increased, thus contributing to the electrochemical performance. The specific capacity of 20Li 2 O-60V 2 O 5 -10B 2 O 3 -10Fe 2 O 3 cathode material increased significantly and the first discharge capacity was as high as 306.2 mA h/g at a current density of 100 mA/g. However, the specific capacity respectively decreased to 239 mA h/g in the second cycle and 120.3 mA h/g after 100 cycles. The study on vanadium-based glass cathode materials provided a new idea for the investigation of novel cathode materials for lithium-ion batteries. [ABSTRACT FROM AUTHOR]

In this study, a novel polyurethane porous 3D scaffold based on polyethylene glycol (PEG) and polytetrahydrofuran glycol (PTMG) was developed by in situ polymerization and freeze drying. Aliphatic hexamethylene diisocyanate (HDI) as a nontoxic and safe agent was adopted to produce the rigid segment in polyurethane polymerization. The chemical structure, macrostructure, and morphology—as well as mechanical strength of the scaffolds—were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), and tensile tests. The results show that the HDI can react mildly with hydroxyl (–OH) groups of PEG and PTMG, while gas foaming action caused by the release of CO2 occurred simultaneously in the reactive process, resulting in a uniform porous structure of PU scaffold. Moreover, the scaffolds were soaked in water and freeze dried to obtain higher porosity and more interconnective microstructures. The scaffolds have a porosity of over 70% and pore size from 100 to 800 μm. The mechanical properties increased with increasing PEG content, while the hydrophilicity increased as well. After immersion in simulated body fluid (SBF), the scaffolds presented a stable surface structure. The gas foaming/freezing drying process is an excellent method to prepare skin tissue engineering scaffold from PTMG/PEG materials with high porosity and good inter connectivity. [ABSTRACT FROM AUTHOR]

A novel white emitting phosphate-based phosphor Ca 3- x Li x (PO 4) 2- x (SO 4) x :Dy3+, Sm3+ with high emission intensity and lower correlated color temperature were successfully synthesized via the sol-gel method. The structures of these prepared phosphors matched well with standard Ca 3 (PO 4) 2. The Dy3+-doped Ca 3- x Li x (PO 4) 2- x (SO 4) x phosphors showed white luminescence via the combination of blue (487 nm) and yellow (578 nm) emissions, which were attributed to the 4F 9/2 → 6H 15/2 and 4F 9/2 → 6H 13/2 electron transitions of Dy3+, respectively. The synthesized phosphor exhibited a significant enhancement in luminescence intensity at the optimum value of x = 0.15. With the incorporation of Sm3+, a warm white emission with lower correlated color temperature (4281 K) was achieved in Dy3+/Sm3+ co-doped samples. The obtained external quantum efficiency reached 21.7% in the optimized phosphor. The improved performance was strongly associated with red emission supplemented by Sm3+, and it demonstrated the existence of efficient energy transfer between the Dy3+ and Sm3+ ions (4F 9/2 → 4G 7/2 and 4F 9/2 → 4G 5/2). Overall, the investigation carried out by us has revealed that the luminescence properties of Ca 3 (PO 4) 2 phosphor can be significantly improved through Li+/S6+ partial substitution and Dy3+/Sm3+ co-doping. Image 1 • A novel Li+/S6+ co-substituted Ca 3 (PO 4) 2 :Dy3+ white-emitting phosphor was prepared. • Ca2+/P5+ couples were partially substituted with Li+/S6+ for luminescence enhancement. • A white light could be realized with a blue emission and yellow emission of Ca 3- x Li x (PO 4) 2- x (SO 4) x :Dy3+. • Warm white emission with low CCT can be achieved for Ca 2 · 85 Li 0 · 15 (PO 4) 1 · 85 (SO 4) 0.15 :Dy3+ phosphor by Sm3+ ions co-doping. [ABSTRACT FROM AUTHOR]