The optimal Seebeck coefficient for obtaining the maximum power factor in thermoelectrics

We propose the existence of an optimal Seebeck coefficient (Sopt) for three-, two-, and one-dimensional thermoelectric materials. This assertion is supported by an exhaustive comparison with experimental data of well characterized bulk thermoelectrics, all of which have shown that the power factor is maximized when Sopt in the range of 130–187 μV/K. Our study serves as a quick guideline for the optimization of thermoelectric materials, and makes the point that efforts should be focused on increasing the electrical conductivity (σ) at the given Sopt.