Browsing by Author "Cai, KF"

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    Alumina template-assisted electrodeposition of Bi2Te2.7Se0.3 nanowire arrays
    (Elsevier, 2010-06-01) Li, XL; Cai, KF; Li, H; Yu, DH; Wang, X; Wang, HF
    Bi2Te2.7Se0.3 nanowire arrays have been fabricated by electrodeposition into the pores of an anodic aluminum oxide (AAO) template followed by annealing at 300°C under Ar atmosphere. The as-prepared nanowires were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray spectroscopy. The nanowires are uniform single crystalline with diameter of ~14 nm. © 2010, Elsevier Ltd.
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    Electrodeposition and characterization of thermoelectric Bi2Te2Se/Te multilayer nanowire arrays
    (Academic Press Ltd- Elsevier Science Ltd, 2011-11-01) Li, XL; Cai, KF; Yu, DH; Wang, YY
    Multilayer nanowire arrays of a new heterogeneous thermoelectric material, Bi(2)Te(2)Se/Te, were successfully fabricated by a template-assisted pulsed electrodeposition method. The nanowires were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, high resolution transmission electron microscopy, and energy dispersive X-ray spectroscopy, respectively. The diameter of the nanowires is in the range of 60-85 nm. By adjusting the concentration of Te precursor, the length of the Te segment can be modulated. At sufficient low concentration of Te precursor, the phase composition of the other segment can even be changed from Bi(2)Te(2)Se to Bi(2)Se(2)Te. The formation and growth mechanisms of the nanowires were proposed. (C) 2011 Elsevier Ltd.
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    Preparation and thermoelectric properties of AgPbmSbSem+2 materials
    (Elsevier, 2008-06) Cai, KF; He, XR; Avdeev, M; Yu, DH; Cui, JL; Li, H
    Hydrothermally synthesized AgPbmSbSem+2 (m = 10, 12, 16, 18) nanoparticles with diameters of 20-50 nm were compacted by pressureless sintering. The Seebeck coefficient and electrical conductivity of the samples were measured from room temperature up to similar to 750 K. The samples show large and positive values of the Seebeck coefficient and moderate electrical conductivity. The thermoelectric properties of AgxPb18SbSe20 (x = 0.8, 0.85) and AgPb(18)Sbse(20-y)Te(y) (y = 1, 3) samples have also been studied. It has been found that Ag0.85Pb18SbSe20 sample has a higher thermoelectric power factor. A significant difference in thermoelectric properties has also been observed for the AgPb18SbSe20 samples prepared with pressureless sintering and spark plasma sintering. © 2008, Elsevier Ltd.
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    Synthesis and thermoelectric properties of single crystalline and polycrystalline Ba8Ga16Ge30
    (Elsevier, 2010-02-18) Wang, HF; Cai, KF; Li, H; Yu, DH; Wang, XC; Zhou, CW; Li, XL; Wang, YY; An, BJ; Du, Y
    Large Ba8Ga16Ge30 single crystals were synthesized by a Ga-flux method. The single crystals were characterized by X-ray diffraction and energy-dispersive X-ray spectroscopy. The cubic structure of Ba filled type-I germanium clathrates with lattice parameter of 10.767 Å has been confirmed. The Ba8Ga16Ge30 polycrystalline sample was prepared by melting the synthesized single crystals. Thermoelectric properties of the single crystalline and polycrystalline Ba8Ga16Ge30 samples were measured from room temperature to 773 K. The single crystalline sample shows p-type conduction, while the polycrystalline sample exhibits n-type conduction and typical heavily doped semiconducting behavior. At room temperature, the electrical conductivity of the polycrystalline sample is much higher than that of the single crystalline sample, whereas the absolute value of Seebeck coefficient of the single crystalline sample is higher than that of the polycrystalline sample. The maximum power factor for the single crystalline and polycrystalline samples reaches ~17 μW cm−1 K−2 at 773 K and ~10 μW cm−1 K−2 at 500 K, respectively. © 2010, Elsevier Ltd.