## 3 Results and Discussion
### Transport Property Evaluation
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Sample**} & \(\mathbf{T_{\text{sint}}}\) & \(\mathbf{t_{\text{hold}}}\) & \(\mathbf{P_{\text{sint}}}\) & \multirow{2}{*}{\(\mathbf{\rho}\) \%} & \multirow{2}{*}{\(\mathbf{T(R)}\)} & \(\mathbf{\kappa}\) & \multirow{2}{*}{\(\mathbf{\sigma(\Omega^{-1}\text{ m}^{-1})}\)} & \multirow{2}{*}{\(\mathbf{\rho}\) \%} & \multirow{2}{*}{\(\mathbf{T(R)}\)} & \(\mathbf{\kappa}\) \\  & (\(\mathbf{{}^{\circ}}\)C) & (min) & & (MPa) & & & (\(\mathbf{W}\) \(\mathbf{m}^{-1}\) \(\mathbf{K}^{-1}\)) & & \(\mathbf{\sigma(\Omega^{-1}\text{ m}^{-1})}\) & \\ \hline Bi\({}_{2}\)Te\({}_{3}\) & 400 & 1 & 50 & 78 & 300 & 0.94788 & \(-\)124.624 & 106356.58 & 20.35 & 0.52 \\  & 440 & 0.87553 & \(-\)159.466 & 80018.39 & 16.52 & 1.04 \\ \cline{2-10} Bi\({}_{1.8}\)Sb\({}_{0.2}\)Te\({}_{3}\) & 400 & 1 & 50 & 83 & 300 & 1.33091 & \(-\)89.190 & 197582.37 & 17.41 & 0.35 \\  & 400 & 1 & 50 & 83 & 523 & 1.05234 & \(-\)128.942 & 104707.34 & 15.72 & 0.87 \\ \cline{2-10} Bi\({}_{0.5}\)Sb\({}_{1.5}\)Te\({}_{3}\) & 400 & 1 & 50 & 78 & 300 & 0.85478 & 104.873 & 40077.90 & 6.81 & 0.15 \\  & 400 & 1 & 50 & 81 & 523 & 0.46612 & 157.339 & 27504.00 & 4.41 & 0.76 \\ \cline{2-10} Sb\({}_{2}\)Te\({}_{3}\) & 400 & 1 & 50 & 81 & 300 & 1.11645 & 104.893 & 230549.91 & 21.94 & 0.68 \\  & & & & & & & & & \\  & & & & & & & & &  
The power factor (PF) (\(S^{2}\)\(\sigma\)) was calculated for all samples, as presented in Figure 3c. The highest PF values were obtained for the pure phase samples of Bi\({}_{2}\)Te\({}_{3}\) and Sb\({}_{2}\)Te\({}_{3}\), followed by Bi\({}_{1.8}\)Sb\({}_{0.2}\)Te\({}_{3}\) and Bi\({}_{0.5}\)Sb\({}_{1.5}\)Te\({}_{3}\). The magnitude of PF is comparable to or higher than that of earlier reports: the maximum power factor at 300 K we achieved are 20.35 \(\mu\)W cm\({}^{-1}\) K\({}^{2}\) for Bi\({}_{2}\)Te\({}_{3}\) and 21.94 \(\mu\)W cm\({}^{-1}\) K\({}^{2}\) for Sb\({}_{2}\)Te\({}_{3}\) pellet, which are much higher than other solution-derived samples--with maximum power factor 1-9 \(\mu\)W cm\({}^{-1}\) K\({}^{2}\)[27, 31]. Thermal conductivity (\(\kappa\)) values were calculated from the thermal diffusivity, density, and C\({}_{\rm p}\) values. The trend is a decrease in \(\kappa\) by increasing temperature, while the values at room temperature (RT) range from about 0.9 to 1.2 W/mK. The sample with the composition Bi\({}_{2}\)Te\({}_{3}\) showed a decreasing trend of \(\kappa\), which increased slightly after 400 K. This was attributed to bipolar effect, likely due to lower \(E_{\rm g}\), thus thermally activated minority carriers in this compound. [PERSON] et al. reported \(\kappa\) values in the range of 0.9-2.4 W/mK at RT for solvothermally synthesized nanoplatelets of Bi\({}_{x}\)Sb\({}_{2-x}\)Te\({}_{3}\)[23]. Our values are similar to, or slightly lower than, their results and even that of bulk ingot Bi\({}_{2}\)Te\({}_{3}\) (1.5 W m\({}^{-1}\) K\({}^{-1}\)). Thermal conductivity has two contributors: electronic (\(\kappa_{\rm el}\)) and lattice (\(\kappa_{\rm lat}\)) components. Nanostructuring is known to reduce the thermal conductivity of the material by phonon scattering, which influences the \(\kappa_{\rm lat}\) mainly. \(\kappa_{\rm el}\) can be estimated using Wiedemann-Franz law, by calculating the electronic contribution (\(\kappa_{\rm el}\)) to the \(\kappa\) and thereafter \(\kappa_{\rm lat}\) can be obtained subtracting  
Figure 3: The temperature dependent transport properties of the synthesized Bi\({}_{2-x}\)Sb\({}_{x}\)Te\({}_{3}\) samples: (**a**) Seebeck coefficient, \(S\); (**b**) electrical conductivity, \(\sigma\); (**c**) Power factor; (**d**) thermal conductivity, \(\kappa\); and (**e**) the overall thermoelectric figure of merit, \(ZT\). \(\kappa_{\text{el}}\) from the total \(\kappa\) (\(\kappa_{tot}\)).