Page 19 - Read Online

Page 14 of 20 Hamawandi et al. Energy Mater. 2025, 5, 500065 https://dx.doi.org/10.20517/energymater.2024.204

Figure 9. Temperature-dependent electronic and thermal transport properties of SPS sintered Sb Te and Bi Te pellets from
2
3
3
2
nanopowders synthesized through MW-assisted thermolysis route; Electrical conductivity-σ (A), Seebeck coefficient-S (B), Power
factor-PF (C), Thermal conductivity-κ (D), and the TE figure of merit ZT (E).
tot
The S mainly demonstrates the type of transport in the TE materials and shows an opposite trend (in
absolute value) to the σ. Figure 9B shows the obtained S values: a negative value for Bi Te starting from
2
3
-70 µV/K at 300 K and reaching -106 µV/K at 575 K; and a positive value for Sb Te , starting at 100 µV/K at
2
3
300 K and reaching to 145 µV/K at 575 K. The sign of S confirms characteristic n- and p-type transport in
the synthesized Bi Te and Sb Te , respectively The S values obtained are in the same order, or slightly lower
3
.
2
3
2
than other solution-derived samples, due to the high σ values obtained for these samples [59,60] .
2
The power factor (PF) (S σ) was calculated for both Bi Te and Sb Te and is graphically presented in
3
3
2
2
Figure 9C. The PF for Bi Te at room temperature was estimated as 9 µW·cm K , and the maximum value
-2
-1
2
3
-1
of 12 µW·cm K was reached at 523 K. For Sb Te , the room temperature value was 19 µW·cm K , and the
-2
-1
-2
3
2
-2
-1
highest value was 22 µW·cm K around 328 K. The magnitude of PF for Bi Te is slightly lower than the
3
2
room temperature PF of samples prepared using other solution-chemical syntheses methods of polyol
(16 μW·cm K ) and hydrothermal (24 μW·cm K ) routes .The difference is mainly attributed to the high
[3]
-2
-1
-2
-1
σ value, and the low S of samples presented in this work. The magnitude of PF obtained for Bi Te and
3
2
Sb Te is, however, higher than many other wet-chemically synthesized TE [61-63] materials with a maximum
3
2
PF of 1-9 μW·cm K .
-1
-2