We report a cost-effective, surfactant-free, and scalable synthesis technique for lead telluride (PbTe) nanocubes by a chemical precipitation method. The high-resolution transmission electron microscopy studies indicated the evolution of nucleation centers (spherical) into nanocubes with the addition of the Pb and Te atoms. The spark plasma sintered PbTe nanocubes exhibited an enhanced Seebeck coefficient, S > +400 µV, higher than the reported values of the bulk PbTe over an extended temperature range of 300–425 K, and a moderate electrical conductivity, σ ∼ 8000 S/m at 300 K. A significant reduction in the lattice thermal conductivity was observed due to effective phonon scattering from the presence of numerous interfaces introduced by nanostructuring. The resulting figure-of-merit (ZT) ∼ 0.45 at 300 K is higher than the reported values at this temperature in other PbTe nanostructures. Moreover, a moderate thermoelectric compatibility factor makes the PbTe nanocubes a potential candidate for green energy generation.

The Seebeck coefficient is an important parameter of thermoelectric materials, which is routinely measured by commercial or home-made equipment based on different methods. However, due to various temperature offsets in the measurement, the determination of temperature gradient can be inaccurate, leading to a large uncertainty in Seebeck coefficient. To elucidate the influence of the inaccurate temperature gradient on the determination of Seebeck coefficient, an error analysis has been performed on a commercial system. Several potential factors that may affect the establishment of temperature gradient were discussed in detail. A comparison between the single point method and the slope method was made to verify which is more accurate to calculate the Seebeck coefficient from the raw measurement data. It is suggested that the slope method is more preferable and the single point method can also be accurate enough when a relatively large temperature gradient is adopted.