Effect of Ag or Sb addition on the thermoelectric properties of PbTe

Abstract

In this study, the effect of Ag or Sb addition on the thermoelectric properties of PbTe including the Seebeck coefficient, the electrical resistivity, and the thermal conductivity, was studied in the temperature range from 323 to 723 K. The major carriers in the Ag-doped and the Sb-doped PbTe are holes and electrons, respectively. A degenerate semiconductor behavior in the electrical transport properties was observed in the Ag-doped, whereas the semi-metallic in the Sb-doped. It was suggested from the results of the Hall effect measurement and the Seebeck coefficient that the effective mass was significantly altered by the Sb-doping. The maximum dimensionless figure of merit, ZT, of Pb1−xAgxTe and Pb1−xSbxTe (x=0.1) alloys showed 0.27 and 0.62 at 723 K, respectively. Based on the analysis of the Seebeck coefficient of the Ag or the Sb-doped PbTe, the interaction between Ag and Sb in PbTe, as expected in the AgPbmSbTem+2 (LAST-m), may be supposed.

Enhancement in thermoelectric performance of n-type Pb-deficit Pb-Sb-Te alloys

“…In Pb-deficit compositions, the highest zT of 0.81 is achieved at 623 K for the 4 mol% Sb containing sample. Both of the 1 mol% and 12 mol% Sb containing samples exhibit zT of 0.6 at 623 K. The zT values of these self-deficit Pb0.98-xSbxTe compositions are much higher than the values for pristine Pb1-xSbxTe compositions reported by Dow et al, [28]. For instance, the 4 mol% Sb containing Pb-deficit sample with the nominal composition Pb0.94Sb0.04Te exhibits zT of 0.81 at 623 K. While it was reported that, for the same dopant concentration in pristine composition (Pb0.96Sb0.04Te), the zT obtained was only 0.3 at the same temperature [28].…”

“…Both of the 1 mol% and 12 mol% Sb containing samples exhibit zT of 0.6 at 623 K. The zT values of these self-deficit Pb0.98-xSbxTe compositions are much higher than the values for pristine Pb1-xSbxTe compositions reported by Dow et al, [28]. For instance, the 4 mol% Sb containing Pb-deficit sample with the nominal composition Pb0.94Sb0.04Te exhibits zT of 0.81 at 623 K. While it was reported that, for the same dopant concentration in pristine composition (Pb0.96Sb0.04Te), the zT obtained was only 0.3 at the same temperature [28]. In the case of pristine compositions, the highest value of zT obtained at 623 K was only 0.5 for Pb0.9Sb0.1Te, which then reaches to a maximum of 0.6 at 723 K. The better TE performance of Pb-deficit samples is due to their better electrical conductivity and lower thermal conductivity when compared to pristine Pb1-xSbxTe [28].…”

“…For instance, the 4 mol% Sb containing Pb-deficit sample with the nominal composition Pb0.94Sb0.04Te exhibits zT of 0.81 at 623 K. While it was reported that, for the same dopant concentration in pristine composition (Pb0.96Sb0.04Te), the zT obtained was only 0.3 at the same temperature [28]. In the case of pristine compositions, the highest value of zT obtained at 623 K was only 0.5 for Pb0.9Sb0.1Te, which then reaches to a maximum of 0.6 at 723 K. The better TE performance of Pb-deficit samples is due to their better electrical conductivity and lower thermal conductivity when compared to pristine Pb1-xSbxTe [28]. This reduction in  for self-deficient samples is expected to arise from phonon-scattering at the vacancies, which act as point-defects [37] and suppresses the lattice contribution by about 50%, when compared with pristine Pb1-xSbxTe [28].…”

“…Our investigation of the thermoelectric properties of Pb0.98-xSbxTe system was motivated by a past study on the n-type self-deficit Pb0.96Sb0.02Te1-xSex bulk materials, where a strong reduction of latt and an enhanced zT was reported [27]. Improvising on that work, where the Sb content was kept fixed while the Se content was varied, herein we try to understand the effect of variation of Sb content on the thermoelectric properties of Se-free Pb0.98-xSbxTe solid solutions and to compare the performance of these Pb-deficit samples with that of previously reported [28] pristine Pb1-xSbxTe compositions. Though several works have been done in the past to exploit the thermoelectric phenomenon in PbTe based alloys, including Sb doped PbTe, not much information is available on the Sb doped, Pb deficient composition (Pb0.98Te).…”

Thermoelectric properties of nanoporous three-dimensional graphene networks

“…The thermal conductivity values increases from 0.54-0.90 W/mK over temperature range of 298-773 K, due to electron-phonon nonequilibrium at high electron temperatures. 20 This can be explained using the WiedemannFranz law, 21 K e ¼ rLT e , where r is charge conductivity, L is the Lorenz number (¼2.45 E-8 WXK À2 ), 22 and T e is the electronic temperature. In our samples, the contribution of phonons is dominant over the entire temperature range, as evidenced from electronic thermal conductivity values ( Fig.…”