Exploration and Optimization of Tellurium‐Based Thermoelectrics

slightly larger dispersion than the S coefficients. Samples were tested for reproducibility. Legends
depict samples in order of decreasing magnitude.
Figure 8.8 ZEM measurements on [Tr] xSnBi 2‐xTe 4: heavy element substitution (top), light element substitution (bottom).
Since there is no understandable order in either the Seebeck or electrical conductivity from
these plots, one is pigeonholed into observing only the magnitude of the power factors shown above. In
short, the ternary compound is still the highest magnitude measured, with a maximum power factor of
~8 W∙cm ‐1 K ‐2 (380 K) with Ga0.05SnBi1.95Te4 following closely with ~7.5 W∙cm ‐1 K ‐2 (440 K) due to the
suspiciously high 1180 ‐1 cm ‐1 at room temperature. Nevertheless, it can be seen that the general
trend for additional triel/V elements leads to a reduction of the compound’s performance.
Displayed below is the thermal conductivity data obtained for the lighter substituents. Due to
the underwhelming similarity of the values and potentially difficult graphic interpretation, Tl, Nb, and Ta
data are omitted from Figure 8.9. The vast majority of the measurements yielded the same magnitude
as SnBi2Te4, though Tl0.05SnBi1.95Te4, Nb0.05SnBi1.95Te4, and Ga0.05SnBi1.95Te4 were all above 1 W∙m ‐1 K ‐1 , the
largest of which is displayed at the top of the thermal conductivity graph below. The intense increase in
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