Effect of heat treatment on the electrical and thermoelectric properties of Sb doped Bi₂Se₃

Abstract

Polycrystalline samples of (Bi 0.95 Sb 0.05 ) 2 Se 3 were prepared using the conventional melting technique at 1273 K, followed by annealing at different temperatures (423, 473, 523 and 573 K) for different time intervals (4, 8, 12 and 16 h). The samples were crystallized in a single phase of Bi 2 Se 3 and no other phases or impurities were observed. The electrical and thermoelectric properties were studied by measuring the electrical conductivity and Seebeck coefficient as functions of temperature in the range 100-400 K. The results exhibited a metal-n-type semiconductor transition for all samples. The power factor (Pf) was calculated to determine the effect of the annealing treatment on the performance of the prepared material as a thermoelectric power generator. The highest room temperature value of the Pf was 6.9 μWK −2 cm −1 and was recorded for the sample annealed at 573 K for 16 h. The results confirm the feasibility of using the annealing process to improve the performance of thermoelectric materials.

Thermoelectric Properties of Hf2−xTixFeNiSb2 double-half Heusler alloys

“…Room-temperature total (k tot ), lattice (k l ) and electronic (k e ) thermal conductivities, porosity (p), as well as the corrected values of the thermal conductivity (k eff ) of the concerned samples. primarily attributed to significantly improving the charge carrier concentration [25,26]. The maximum value of electrical conductivity was achieved for Hf 1.85 Ti 0.15 FeNiSb 2 which was 35 992 ± 1793 W -m 1 1 at 800 K, which agrees with the previously reported experimental results for Ti 2 FeNiSb 2 doped with Hf [22].…”

Reduction in thermal conductivity and electrical resistivity of indium and tellurium co-doped bismuth selenide thermoelectric system

“…Electrons will settle within the conduction band, which elevates the Fermi level to higher energy as a result of the co-doping in Bi 2 Se 3 . This is presumably due to the super-stoichiometry and/or point defects that play a major role in the crystal lattice [47]. The change in the effective mass may be the reason for the unexpected decrease in the activation energy of the In-doped sample with x = 0.04.…”

The electric and thermoelectric properties of Cu(II)-Schiff base nano-complexes

“…The efficiency of the TE materials is determined by the figure of merit ZT = S 2 σ/K where S is the Seebeck coefficient, σ is the electrical conductivity and K is the thermal conductivity. It is hard to achieve high ZT for the traditional TE materials (such as chalcogenide based materials) because all the three ZT parameters (S, σ and K ) are highly correlated where up to now there is no method suggested for enhancing the electrical conductivity without associated decrease of both the Seebeck coefficient and thermal conductivity values [13][14][15]. To overcome this challenge, many attempts have been made to enhance the electrical conductivity of organic complexes by incorporation of highly conductive materials such as single wall carbon nanotubes (SWCNTs), multi wall carbon nanotubes (MWCNTs), metals or graphene in order to increase their efficiency as TE power generators.…”