Search

Bismuth telluride (Bi 2 Te 3) is a widely used thermoelectric (TE) material in practical applications. However, it contains expensive and toxic tellurium, a promising TE material should include low-cost and non-toxic element. Bismuth selenide (Bi 2 Se 3) is similar to Bi 2 Te 3 in electronic and crystal structure. The electron effective mass of Bi 2 Se 3 is smaller than that of Bi 2 Te 3 , while its electrical transport performance is inferior to that of Bi 2 Te 3. Therefore, in this study, Cl and K co-doped Bi 2 Se 3 thermoelectric material with high density, low thermal conductivity, and excellent thermoelectric performance was prepared using KCl as the solvent. It is found that the effective electron mass and carrier concentration of the doped sample is effectively improved, which significantly increases the doped sample's electrical transport properties and ZT value. Finally, the Bi 2 Se 3 (KCl) 3.5 sample reached a maximum ZT value of 0.79 at 550 K, and the average ZT in the measured temperature range reached 0.45. [ABSTRACT FROM AUTHOR]

In this study, PbSe single crystal with the grain size of 10 mm was prepared using Pb-flux method combined with melt slow cooling process, and its structure and thermoelectric transportation properties were systematically studied. X-Ray powder diffraction results indicated that all prepared samples has a NaCl-type crystal structure with a space group of F m 3 ¯ m. Transmission electron microscopy and the corresponding selected area electron diffraction results illustrated that the sample prepared by this method was a single crystal. Thermal analysis showed insignificant weight loss in the PbSe sample below the melting point, thereby indicating that PbSe has good thermal stability. X-Ray photoelectron spectroscopy results demonstrated that the valences of Pb and Se were +2 and −2, respectively. Given that the PbSe sample had a high mobility, the material has a high electrical conductivity near room temperature. Thus, the ZT value near room temperature reaches 1.25, which indicates that single crystal PbSe obtained by Pb flux method has potential application in room-temperature power generation. [ABSTRACT FROM AUTHOR]