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Introduction of Bismuth Telluride

Bismuth telluride is the dominant thermoelectric material for applications near room temperature due to its inherently low lattice thermal conductivity and high electronic weighted mobility. Its performance is ultimately limited by the harmful effects of thermally generated minority carriers due to its small band gap (0.14 eV). This effect can be partially mitigated by doping more heavily than ideal, considering the transport of most carriers alone. Combining Sb2Te3 for p-type or Bi2Se3 for n-type materials can reduce bipolar effects by increasing the band gap. Still, the impact on thermal and electric transports must also be considered. Thermal conductivity can be significantly reduced by the enhanced scattering of high-frequency phonons by introducing mass contrast and bonding changes. Charge carrier mobility can also be disrupted during alloying, while changes in electronic structure could prove beneficial or detrimental. Engineering bismuth telluride-based thermoelectrics requires simultaneous consideration of these details. The p-type Bi2Te3-Sb2Te3 alloy has been well characterized and modeled. The thermal conductivity variation with composition is well described using a mass contrast alloy scattering model where composition varies on a single cation site. The valence band structure for both binary compounds is similar, with the primary difference being a switch in the order of the two valence band maxima. These band edges cross in energy near Bi0.5Sb1.5Te3, enhancing the thermoelectric power factor. This convergence in energy combined with a significant reduction in thermal conductivity leads to this being the optimum composition. If you are looking for high quality, high purity, and cost-effective Bismuth Telluride, or if you require the latest price of Bismuth Telluride, please feel free to email contact mis-asia.

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