Synthesis, structure, and high-temperature thermoelectric properties of boron-doped Ba8Al14Si31 clathrate I phases.
نویسندگان
چکیده
Single crystals of boron-doped Ba8Al14Si31 clathrate I phase were prepared using Al flux growth. The structure and elemental composition of the samples were characterized by single-crystal and powder X-ray diffraction; elemental analysis; and multinuclear (27)Al, (11)B, and (29)Si solid-state NMR. The samples' compositions of Ba8B0.17Al14Si31, Ba8B0.19Al15Si31, and Ba8B0.32Al14Si31 were consistent with the framework-deficient clathrate I structure Ba8Al(x)Si(42-3/4x)cube(4-1/4x) (x = 14, cube = lattice defect). Solid-state NMR provides further evidence for boron doped into the framework structure. Temperature-dependent resistivity indicates metallic behavior, and the negative Seebeck coefficient indicates that transport processes are dominated by electrons. Thermal conductivity is low, but not significantly lower than that observed in the undoped Ba8Al14Si31 prepared in the same manner.
منابع مشابه
Induction annealing and subsequent quenching: effect on the thermoelectric properties of boron-doped nanographite ensembles.
Boron-doped nanographite ensembles (NGEs) are interesting thermoelectric nanomaterials for high temperature applications. Rapid induction annealing and quenching has been applied to boron-doped NGEs using a relatively low-cost, highly reliable, laboratory built furnace to show that substantial improvements in thermoelectric power factors can be achieved using this methodology. Details of the de...
متن کاملSynthesis, Structure, Thermoelectric Properties, and Band Gaps of Alkali Metal Containing Type I Clathrates:
A series of alkali metal containing compounds with type I clathrate structure, A8Ga8Si38 (A = K, Rb, Cs) and K8Al8Si38, were synthesized and characterized. Room temperature lattice parameters of A8Ga8Si38 (A = K, Rb, Cs) and K8Al8Si38 were determined to be 10.424916(10), 10.470174(13), 10.535069(15), and 10.48071(2) Å, respectively. The type I clathrate structure (cubic, Pm3 ̅n) was confirmed fo...
متن کاملFacile Fabrication of Boron-Doped Titania Nanopowders by Atmospheric Pressure Chemical Vapor Synthesis Route and its Photocatalytic Activity
The Atmospheric Pressure Chemical Vapor Synthesis (APCVS) route is a process that can be used for the synthesis of doped-nanocrystalline powders with very small crystallite sizes having a narrow particle size distribution and high purity. In this study, APCVS technique was used to prepare boron-doped titania nanopowders. The effects of temperature, borate flow rate and water flow rate on the am...
متن کاملPrediction of a large number of electron pockets near the band edges in type-VIII clathrate Si46 and its physical properties from first principles.
The material design of type-VIII clathrate Si46 is presented based on first principles. The structural, electronic, elastic, vibrational, and thermodynamic properties of this hypothetical material are presented. Our results predict that type-VIII clathrate Si46 is an indirect semiconductor with a bandgap of 1.24 eV. The band structure revealed an interestingly large number of electron pockets n...
متن کاملThe Effect of Annealing, Synthesis Temperature and Structure on Photoluminescence Properties of Eu-Doped ZnO Nanorods
In this study un-doped and Eu-doped ZnO nanorods and microrads were fabricated by Chemical Vapor Deposition (CVD) method. The effects of annealing, synthesis temperature and structure on structural and photoluminescence properties of Eu-doped ZnO samples were studied in detail. Prepared samples were characterized using X-Ray diffraction (XRD), scanning electron microscopy (SEM), particle size a...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Inorganic chemistry
دوره 47 18 شماره
صفحات -
تاریخ انتشار 2008