Xinjiang Key Laboratory of Electronic Information Materials and Devices

Urunchi, China

Xinjiang Key Laboratory of Electronic Information Materials and Devices

Urunchi, China

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Hua N.,CAS Xinjiang Technical Institute of Physics and Chemistry | Hua N.,University of Chinese Academy of Sciences | Hua N.,Xinjiang Key Laboratory of Electronic Information Materials and Devices | Wang C.,CAS Xinjiang Technical Institute of Physics and Chemistry | And 8 more authors.
Journal of Alloys and Compounds | Year: 2010

Alien atom doping has been adopted to modify the electrochemical performance of olivine type LiFePO4 for cathode material. Here, we report that vanadium-doping can improve the performance of LiFePO4/C immensely. LiFePO4/C and V-doped LiFePO4/C cathode materials were first synthesized by carbothermal reduction method. Physico-chemical characterizations were done by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Electrochemical behavior of the cathode materials was analyzed using cyclic voltammetry (CV) and galvanostatic measurements. ICP and XRD analyses indicated that V ions were sufficiently doped in LiFePO4 and did not alter its crystal structure and exhibited the variation of lattice parameters with the doped degree. From the CV, the V ion doping affected the Li+ ionic diffusion coefficient during both the delithiation and lithiation processes and it became larger with an appropriate amount doping. From the results, it is noted that vanadium ions doping can improve performance of LiFePO4, especially on the aspect of stable cycle-life at higher C rate. © 2010 Elsevier B.V. All rights reserved.


Zou W.,University of Electronic Science and Technology of China | Wang Y.,University of Electronic Science and Technology of China | Wang Z.,University of Electronic Science and Technology of China | Zhou A.,University of Electronic Science and Technology of China | And 6 more authors.
Nanotechnology | Year: 2011

We report a novel method to fabricate ordered arrays of gold-polymer composite nanorods with the orientation in the vertical direction using block copolymer (BCP) film. The salt precursor is selectively infiltrated within vertically aligned cylindrical domains of the BCP film by immersing the template in a simple aqueous solution of HAuCl4. Scanning electron microscopy suggests that the salt might be uniformly positioned along the polymeric cylinders. A subsequent vacuum ultraviolet light irradiation simultaneously reduces the HAuCl4 into spherical gold nanoparticles with mean diameter around 2nm and removes the matrix of the BCP template to produce metal-polymer composite nanorods. While the solvent is methanol, the salt might be concentrated at the bottom of the BCP film. As a result, a periodic pattern of gold nanoparticles with average diameter around 11nm is formed where the BCP film is completely etched away. The solvent can effectively tune the spatial distribution of the salt precursor along the polymeric cylinders, which is responsible for the different morphologies of the photochemically fabricated nanostructures. © 2011 IOP Publishing Ltd.


Li J.,Chinese Academy of Sciences | Wang L.,Xinjiang Key Laboratory of Electronic Information Materials and Devices | Bian L.,Xinjiang Key Laboratory of Electronic Information Materials and Devices | Zhao P.J.,Xinjiang Key Laboratory of Electronic Information Materials and Devices | And 2 more authors.
Advanced Materials Research | Year: 2013

The pure and Zr-doped BiFeO3 thin films were fabricated on Pt/TiO2/SiO2/Si substrates by sol-gel method. The microstructural characterization revealed a phase structural transition from rhombohedral structure to tetragonal structure in Zr-doped BiFeO3 thin films. Compared with pureBiFeO3 thin film, the Zr-doped BiFeO3 thin films showed better dielectric and leakage current characteristics. The mechanism associated with the enhancement of the electrical properties of the thin films is also discussed. © (2013) Trans Tech Publications, Switzerland.


Bian L.,Chinese Academy of Sciences | Xu J.-B.,Xinjiang Key Laboratory of Electronic Information Materials and Devices | Song M.-X.,South University of Science and Technology of China | Dong H.-L.,Miami University Ohio | Dong F.-Q.,South University of Science and Technology of China
RSC Advances | Year: 2013

To observe the high-temperature ferro-electricity at room-temperature, we used a halogen to create a 2p-hole for improving O-Fe p-d electronic transition, and calculated the systematic variations in electronic and magnetic properties using first-principle calculation. The systems prefer to charge disproportionate as Fe3+-O2--Fe2+ with the highly localized halogen concentration increasing, where the O-site halogen creates a 2p-hole to disproportionate Fe charge from Fe3+-d5 orbital with a full-filled triple degeneracy orbits (t2g) orbital to Fe 2+-d5-d0 with a partially filled t2g orbital. Whatever at room-temperature or high-temperature phase, the halogen substitutes, typically, for F (or Cl)-doping, induce the electrons to transfer from O-2p4 → unoccupied Fe3+-3d5 to O-2p4→Bi3+-6p3, while the ferromagnetic (FM)-anti-ferromagnetic (AFM) phase transits at about 1 atom per cell. Furthermore, to retain O-Fe electron transfer process, we applied the crystallographic anisotropy to produce the strong Fe-O orbital hybridization which offsets the effect of 2p-hole, and it causes more significant O-2p 4 → unoccupied Fe3+-d5 electronic transitions at the valence band. This study opens a new perspective to the development of multiferroic devices with independent temperature. This journal is © The Royal Society of Chemistry.


Wang L.,CAS Xinjiang Technical Institute of Physics and Chemistry | Wang X.,CAS Xinjiang Technical Institute of Physics and Chemistry | Chen Z.,Xinjiang Key Laboratory of Electronic Information Materials and Devices | Ma P.,CAS Xinjiang Technical Institute of Physics and Chemistry
Applied Clay Science | Year: 2013

Vermiculite (Verm)/polystyrene (PS) nanocomposites were prepared by dispersing a doubly organo-modified Verm (DOVerm) in PS via in situ polymerization (DOVerm/PS 1/99, 3/97, 5/95, and 7/93 mass/mass ratios). The morphology of Verm/PS nanocomposites evolved three stages as the content of DOVerm decreased in the nanocomposites: intercalation at high filler content, intermediate state of intercalation to exfoliation, and exfoliation of Verm in PS matrix with a low filler content. The morphological changes of Verm/PS nanocomposites were confirmed by the X-ray diffraction (XRD) patterns and the transmission electron microscopy (TEM) images. Compared with the pure PS, the nanocomposites filled with Verm showed significant enhancements on thermal stability and dynamic mechanical properties. Interestingly, the nanocomposites filled with 1 and 7 mass% of DOVerm exhibited more pronounced effects of Verm on the properties. It was proved that the double organo-modification clearly enhanced the ultimate properties of the Verm/PS nanocomposites. © 2013 Elsevier B.V.


Zhang H.,CAS Xinjiang Technical Institute of Physics and Chemistry | Zhang H.,Xinjiang Key Laboratory of Electronic Information Materials and Devices | Zhang H.,University of Chinese Academy of Sciences | Chang A.,CAS Xinjiang Technical Institute of Physics and Chemistry | And 4 more authors.
Microelectronic Engineering | Year: 2011

Based on spinel-type semiconducting electroceramics, negative temperature coefficient (NTC) thermistor materials, Ni 0.9Co 0.8Mn 1.3-xFe xO 4 (0 ≤ x ≤ 0.7), with different compositions were synthesized by a co-precipitation method. The optimal pH value and the influence of Fe 3+ doping during the synthesis processing were discussed. As-prepared Ni 0.9Co 0.8Mn 1.3-xFe xO 4 materials were characterized by DT/TGA, XRD, FTIR, SEM, electrical measurement and impendance analysis. It was found that, as the Fe doping content in the Ni 0.9Co 0.8Mn 1.3-xFe xO 4 samples increased, both the grain size and the density decreased. The as-sintered Ni 0.9Co 0.8Mn 1.3- xFe xO 4 samples presented a single-phase cubic spinel structure. The impendance diagram indicated that the grain boundary resistance was dominant in the overall impendance of Ni 0.9Co 0.8Mn 1.3-xFe xO 4 NTC ceramic materials. The value of ρ 25, B 25/50, slope and activation energy for the samples Ni 0.9Co 0.8Mn 1.3-xFe xO 4 sintered at 1200 °C were in the range of 453.1-2411 Ω cm, 3103-3355 K, 3.27325-3.43149 and 0.28207-0.29325 eV, respectively. This suggests that the electrical properties can be adjusted to desired values by controlling the Fe 3+ ion doping content. © 2011 Elsevier B.V. All rights reserved.


Li J.Z.,University of Electronic Science and Technology of China | Li J.Z.,University of Sichuan | Li J.Z.,Xinjiang Key Laboratory of Electronic Information Materials and Devices | Wang Y.,University of Electronic Science and Technology of China | And 8 more authors.
Ultramicroscopy | Year: 2010

Three metal salts, i.e., AgNO3, HAuCl4, and KCl, were proposed as novel staining reagents instead of traditional RuO4 and OsO4 labeled with expensive price and extreme toxicity for scanning electron microscopy (SEM) imaging of microphase separated block copolymer film. A simple and costless aqueous solution immersion procedure could ensure selective staining of the metal slat in specific phase of the nanostructured copolymer film, leading to a clear phase contrasted SEM image. The heavy metal salt has better staining effect, demonstrating stable and high signal-to-noise SEM image even at an acceleration voltage as high as 30kV and magnification up to 250,000 times. © 2010 Elsevier B.V.


Gai M.,CAS Xinjiang Technical Institute of Physics and Chemistry | Gai M.,Xinjiang Key Laboratory of Electronic Information Materials and Devices | Gai M.,University of Chinese Academy of Sciences | Chen Z.,CAS Xinjiang Technical Institute of Physics and Chemistry | And 5 more authors.
Journal of Rare Earths | Year: 2013

The objective of this work was to develop possible materials for optically stimulated luminescence (OSL) dosimetric applications in real-time measurement. A novel material of LiMgPO4:Tb,Sm,B was prepared by solid-state diffusion method at 900 °C. The structure and optical properties of these phosphors were characterized by X-ray diffraction, fluorescence spectrophotometer, and OSL reader. The results showed that the full discrimination between the stimulation and emission spectra made them very fit for the optic-fibre dosimetry. The OSL vs. dose response was linear in the dose range of 0.1 to 216 Gy. It also showed a significant improvement in the stimulation time compared with LiMgPO4:Tb,B. Hence, the phosphor could be used in the real-time dosimeter based on the OSL technology for medical monitoring as well as for environmental dosimetry and space dosimetry.


Wang L.,CAS Xinjiang Technical Institute of Physics and Chemistry | Wang L.,University of Chinese Academy of Sciences | Wang L.,Xinjiang Key Laboratory of Electronic Information Materials and Devices | Chen Z.,CAS Xinjiang Technical Institute of Physics and Chemistry | And 9 more authors.
Applied Clay Science | Year: 2011

The intercalation of alkylammonium ions into vermiculite (VMT) to improve the interior structure of VMT has evolved into a subject of tremendous interest. The Na+-exchanged vermiculite (Na-VMT) prepared from the VMT in Xinjiang area (China), served as a host for intercalation with cetyl-trimethylammonium (CTA+) to prepare organo-vermiculites (OVMTs) by a typical hot solution method (OVMT (H)) and a novel ball milling method (OVMT (M)) under the optimized conditions confirmed by orthogonal experimental designs. The two methods employed thermal energy and mechanical energy respectively to drive the CTA+ cations into the interlayer space of layers and to carry out the cation exchange reaction. From X-ray diffraction (XRD) patterns, scanning electron microscopy (SEM) images and thermogravimetric analysis (TGA) results, the Na-VMTs were structurally modified, and the OVMTs showed remarkably large interlayer spaces, in which alkyl chains built paraffin-type bilayer arrangements nearly perpendicular to silicate layers. However, hot solution and ball milling methods showed different behaviors. The interlayer distance of the OVMT (M) (4.283nm) was larger than that of the OVMT (H) (4.052nm), indicating that the tilting angle of alkyl chains in the former was larger than that in the latter. Additionally, the hot solution treatment retained the morphology of the layers and reduced the surface energy of the VMT, whereas the ball milling method caused layers to twist and led to high residual surface energy on the particles, as well as a higher content of organic compounds and lower thermal stability for the product. © 2010 Elsevier B.V.


Li C.,CAS Xinjiang Technical Institute of Physics and Chemistry | Li C.,University of Chinese Academy of Sciences | Li C.,Xinjiang Key Laboratory of Electronic Information Materials and Devices | Hua N.,CAS Xinjiang Technical Institute of Physics and Chemistry | And 11 more authors.
Journal of Alloys and Compounds | Year: 2011

Olivine composites LiFe1-xMnxPO4/C (x = 0, 0.05, 0.1) were prepared by chelation assisted mechanochemical activation method using C2H2O4 as the chelating reagent. The structures of the prepared composites were characterized by X-ray diffraction (XRD). Cyclic voltammetry, ac impedance spectroscopy, galvanostatic charge/discharge performances were studied at room temperature. The discharge capacity of LiFe0.95Mn0.05PO4 was 155.6 mAh g-1 and 102.9 mAh g-1 at 1 C and 10 C rate, respectively. The results indicated Mn2+-doping in LiFePO4 could effectively enhance the electrochemical performances of this olivine compound especially at high charge/discharge rate. In addition, charge/discharge method was also used to characterize the low temperature properties of the different samples. The results showed that the lower the operation temperature was, the poorer the performances were. Furthermore, ac impedance measurement was used to understand the factors of the poor performances at low temperature. © 2010 Elsevier B.V. All rights reserved.

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